Digital PDFs

DEC-08-OCSTA-B-D

May 1973

111 pages

Original

4.4MB

Document:	Introduction to DIBOL 197305
Order Number:	DEC-08-OCSTA-B-D
Revision:
Pages:	111
Original Filename:	http://bitsavers.org/pdf/dec/pdp8/dibol/DEC-08-OCSTA-B-D_Introduction_to_DIBOL_197305.pdf

OCR Text

INTRODUCTION
TODIBOL
Digital's Business. . Qriented Language
A Programmed Text

-------~~o~oomo---------

DEC-08-0CST A-B-D

DIBOL
Self-Instruction Manual
(AN INTRODUCTION TO DIBOL)

For additional copies of this manual, order DEC-08-0CSTA-B-D from
the Software Distribution Center, Digital Equipment Corporation,
Maynard, Massachusetts 01754

First Printing, July 1972
Revised May 1973

1972, 1973 by Digital Equipment Corporation

The material in this manual is
for information purposes and is
subject to change without notice.

The following are registered trademarks of Digital Equipment
Corporation, Maynard, Massachusetts
DEC
FLIP CHIP
DIGITAL
DIBOL
OMNIBUS
DECmagtape

PDP
FOCAL
COMPUTER LAB
LAB8/e
DECtape
UNIBUS

CONTENTS

INTRODUCTION
Developments in Small Business Data Processing
Commercial Data Processing Terminology
DIBOL - A Programming Language
Eight Types of Statements
Language Features
Commercial Operation System
COMPILER
'Monitor &
Editor
SYSGEN
PIP
Data File Creation and Maintenance Programs
BUILD
UPDATE
SORT
Uti Ii ty Programs
CREF

DAFT
MARK
BOOT
PATCH
Manual and System Conventions

Introduction - 1
Introduction - 3
Introduction - 5
Introduction - 5
Introduction - 6
Introduction - 7
lntioduction ~ 7
Introduction - 7
Introduction - 7
Introduction - 8
Introduction - 8
Introduction - 8
Introduction - 8
Introduction - 8
Introduction - 8
Introduction - 9
Introduction - 9
Introduction - 9
Introduction - 9
Introduction - 9
Introduction - 9
Introduction - l 0

BASIC SOURCE LANGUAGE PROGRAMMING
Flowcharting - frames 1-5
A DIBOL Coded Program - frames 6-25
Sample Problem Summary
Basic Operating Steps - frames 26-30

1- 1
1- 2
1- 2
1- 8
l - 9

DiBOL SYNiAX

'L-1
"' .,

Data Section
START, PROC, END - frames 1-5
RECORD - frames 6-12
P OPTION - frame 13

D OPTiO N - frame 14
iNiTlAUZATiON-SPECiFiCATiON - frames 15-20
RECORD, X (overlay) - frames 21 -27
Data Section Summary
Procedure Section - frames 28-29
IN IT - frames 30-35
XM IT - frame 36
FINI - frame 37
Data Manipulation - frames 38-50
ALPHA=ALPHA - frames 40-41
DEC lf'v1AL=DEC lMAL ~ frames 42~44
Decimal to/from Alpha - frames 45-46
Decimal to Alpha with Format ~ frames 47-50
GO TO - frames 51 -55
IF - frames 56-58
CALL, RETURN - frame 59
STOP
lnventor1 Problem Explanation

INCR - frame 71
FORMS - frame 72
TRACE, NO TRACE - frames 73-74
ON ERROR - frames 75-76
ACCEPT - frames 77-78
DISPLAY - frames 79-80
READ, WRITE - frame 81
Inventory Records Problem Explanation
Section Summary
A PROGRAMMING EXERCISE
ADVANCED DIBOL STATEMENTS
Rounding - frames 1-5
Character Conversion - frames 6-10
Source Files - frames 11-13
TRAP - frames 14-15
CHAINING - frames 16-23

2-2
2-2
2- 2
2-5

iii

2-6
,...
,
L-o

2-8
2 - 11
2 - 12
2 - 12
2 - 14
2 - 15
2 - 15
2 - 16
2 - 19
2 - 20
2 - 22
2 - 24
2 - 25
2 - 26

2 - 28
2 - 29
2 - 29
2 - 30
2 - 31
2 - 32
2 - 33
2 - 35
2 - 36
2 - 37
3- 1
4 - 1

4-2
4 - 3

4-4
4-6

4-8

APPENDIX A - Invoice Data Entry Program
APPENDIX B - Standard Flowchart Symbols
GLOSSARY - COS 300 Glossary of Standard Technology

A- l
B- l
Glossary - l

FOLDOUT ILLUSTRATIONS
Foldout #1
Foldout #2
Foldout #3
Foldout #4

Sample Program Flowchart
Figure 1-1, Basic Operating Steps
Sample Program #2
Sample Program #3

l - 7
1- 9
2 - 27

2 - 35

INTRODUCTION

In this self-instruction text you will learn the fundamentals for using
Dlgital 1 s Business Oriented Language - DIBOL. This compiler
language is used tO-describe-data-processing problems for the DEC
DATASYSTEM 300 series computers. DIBOL is an integral part of the
Series 300 ~ommercial Operating ~stem - COS 300.
When you complete this course you should be able to program workable solutions to real problems in Billing, Accounts Receivable,
Sales Analysis, Inventory Applications, and others. Given an application problem, you should be able to use DIBOL to develop a source
computer program that can be compiled and run on the COS 300
System.
However, there are elements of the COS 300 software system that are
not taught in this manual. You will find these in the COS 300 System
Reference Manual (Order Number DEC-08-0COSA-E-D).
This course presents sets of instructions, questions and answers in
frames. Each question is foiiowed by the correct answer. Foid-out
pages are provided so that you may refer to examples of flowcharting,
coding, problems, etc., as you progress. Additional problems are
supplied to reinforce your knowledge through application. A summary
is provided at the end of each chapter. AG lossary of terms is included for quick reference. Although this programmed instruction
will give you a working knowledge of DIBOL, you should try to
compile and run your first programs where computer facilities exist.
An interpretation of course completeness is based on our definition of
a programmer - a person who prepares, or is responsible for, problemsolving procedures. The information presented in this text was prepared for these individuals, in a small to medium sized business
environment, who of necessity may have to wear many 11 hats 11 •
The programmer's hat cliche has significance for the student in that
it suggests the proper way of approaching the subject information.

INTRODUCTION - 1

The programmer must be a specialist in more than one area. In his
preparations he should assume the roles of a job and program analyst,
a computer operator, and most important, the end user of the computer application~
The student should allow himself enough time to complete the course
before attempting applications programming. In the final analysis,
time and money will be saved by proper utilization of the computer.
DEVELOPMENTS IN SMALL BUSINESS DATA PROCESSING
~lectronic ~ata f_rocessing (EDP) technology has advanced to the

point where most businessmen can realistically consider automating
repetitious paper work. At present, thousands of smaH businesses
are inundated with paperwork, payrol I, inventory control, accounts
receivable processing, and numerous other tasks that can be rapidly
and accurately processed by computer.
Un ti I recently, these businesses had no alternative to the service
bureau since the cost of in-house computer configurations were prohibitively expensive. The total system power of a computer which
wouid have cost a haif-miilion doiiars a decade ago can now be
encompassed into a mini-computer desk configuration (DEC
£>ATA,?_YSTEM 300) for less than $30,000.
The technological milestones beginning in the 19601 s were the shifts
from vacuum tubes to transistors, then to Integrated Circuits (IC's),
and most recently to Medium-Scale lntegrotion (MSi). The size of a
computer's Central Processor (CP) was directly related to these
hardware advances.The dramatic reduction in size and cost-per-circuit for the computer
hardware is only part of the array of benefits. A new technology has
emerged and matured as a direct result of millions of dollars worth of
R & D resources expended by large corporations. This transition has
been from tabulating equipment (unit record punched card tabulators dedicated to wired single program operation) to the outstanding
modu farity and resultant flexibility of computer software.

Software is defined as computer control programs which are stored
and/or loaded into the computer's memory banks. The program's
instructions are automatically scanned by the computer's central processor to control job operation.
Not only has software emerged as an integral part of a computer configuration, but its usage has formulated specialized programs and
procedures. These include some of the following:
Implementation Language - programming language by which
business data processing procedures may be precisely described
in a standard form.
System Monitor - a control program to supervise and verify the
correct operation of all running programs including operator/
system interaction.
Utility Programs - standard service or housekeeping programs
used to: sort and merge data, interchange programs and files
which reside on various peripheral devices, update and build
data files, edit and trace data, etc.
Combining the above, we have an operating system - an organized
collection of techniques and procedures for operating a computer.
For the DEC DATASYSTEM, they are part of a software paykage called
the fommercial Qperating ~stem (COS). These job application
software tools no longer require vast amounts of costly storage, nor
does access to them run into minutes as it did with prior computer
generations.Using the hardware and standardized OS programs offered by Digital

in-house programmer should start slowly, developing the most convenient and practical programs first. He should also be prepared to
continually modify programs and al low for new programs and system
features. In this way he will be more responsive to the requirements
of management.
The programmer should also make extensive use of the "conversational mode" type of program. Data should be entered on line using
the Cathode Ray Tube (CRT) display terminal (video screen with keyboard). The program should ask the operator for the required data,
and then accept the answer. As much as possible, answer parameters
should be built into the program. As an example, if the question
from the computer is 11 number ordered? 11 , an answer larger than the
current stock level, or an answer that depletes stock below the
reorder point, should produce a warning message in addition to the
normal accounting within the program. Additionally, the program
could produce an instant-echo for confirmation of back-order
adjustments.
Since the interactive terminal al lows the operator to check and make
corrections to the data before it is transferred to the DECtape or
disk, data can be visually validated. Obviously, conversational
mode programs allow less-experienced operators to produce accurate
records. A good system design will allow the existing clerical staff,
under the guidance of the programmer (via displayed messages and
operating procedures), to operate the computer. An accounts receivable clerk should continue doing receivables, while the person
disbursing che_cks sho_uld .continue doing .that job•- Employees can use
the computer as a sophisticated tool to make each job easier and
more pleasant.

~quipment forporation (DEC), the user can customize an application

system by writing programs to conform to the way his company is conducting its business. He must carefully analyze his company's EDP
requirements as a prerequisite to his system design. This methodical
planning will contribute to a more rapid new system startup.
Initially his programs may be satisfactory, but they soon may become
obsolete as procedures change to better utilize the computer. The

The imaginative programmer can help job operation by preparing both
batch and interactive programs and procedures. Batch processing is a
sequential job stream procedure that uses an accumulation of related
job units. It allows both data items and programs to be collected
into groups for faster processing. Batch processing can be used to
advantage for those cyclical or repetitious jobs. This technique will
save the operator time while making maximum use of the computer.

INTRODUCTION - 2

COMMERCIAL D,.6..T,.6.. PROCESSING TERMINOLOGY
In order to describe and build better business systems, you should be
familiar with the following applications terminology:

FIELD - A subdivision of a record containing one item of information,
e.g., an employee's weekly time card containing his identification number in one FIELD.
FILE -

AUDIT - An operation or check designed to ascertain the validity of
data. The validity of data is verified through the use of
check sums, hash totals, maximums, minimums, redundancies,
cross totals, and various other methods. The AUDIT is used
to insure: that accounting records will not be destroyed,
that the computer system wi 11 not incorrectly read or process data; or that someone will not manipulate data to
produce wrong resu Its. The report generated from an audit
is called the AUDIT TRAIL, e.g., for a payroll application
an AUDIT TRAIL for the validity of input data would contain
error conditions, such as time records for terminated employees; employees with no time records, etc.
BACKUP - Pertains to equipment or procedures that are available for
use in the event of systems failure and destroyed data files
on tape or disk. The provisions for adequate BACKUP
facilities and data files are an important factor in the
design of all data processing systems, e.g., copy of a disk
file on magnetic tape.
DAT A BASE - Data records that must be stored in order to meet the
information processing and retrieval needs of an organization.
The term imp Iies an integrated file of data used by many
processing applications, in contrast to an individual data
file for each sepdrafe appticotion.
EAM -

Electronic Accounting Machine, pertains to data processing
equipment that is predominantly electromechanical such as:
keypunch, collators, sorters. A computer is classified as
EDP equipment. EAM equipment is also known as unit
record or Tab equipment.

INTRODUCTION - 3

A collection of related records. A FILE is usually either a
transaction FI LE or a master FI LE.

FILE LABEL - A LABEL that identifies the FILE. An internal FILE
LABEL is recorded as the first record of a file and is machine
readable. A FILE LABEL is a control feature, e.g., insures
that the operator has the proper master fl ie for updating or
prevents the operator from mistakenly using a master file as
a scratch file.
FILE MAINTENANCE - The updating of a file to reflect the effects
of non-periodic changes, such as adding, changing, or
deleting data, e.g., addition of a new employee to the
employee master file.
FILE PROCESSING - The periodic updating of a master file to reflect
the effects of current data, usually transaction data contained on a transaction fl ie, e.g., weekiy payroi i run that
updates the payro 11 master fit e •
FIXED LENGTH
RECORD - A file containing a set of records, each of which contains
the same number of characters. (Contrast with variable
Iength records) •
IN DEX FtlE - Pertains to a disk file that is organized somewhat Iike
the books in a Iibrary, i.e., an index tel Is where the
record is stored. The index contains two facts about each
record in a file. First, the contents of the record's key
field appears in the index. A key field contains data that
uniquely identifies a record and is the basis for the file's
sequence, e.g., customer number. The disk address
represents the location on the disk where the record can be

COMMERCIAL DATA PROCESSING TERMINOLOGY (cont.)
found. An index label contains the same number of entries
as there are records in the file.
Various terms associated with processing an indexed file are:
index sequential processing, indexed access method, address
routing method. These files may be processed sequentia Ily
or in random fashion.
INTEGRATED DATA
PROCESSING - Data processing by a stream that coordinates a number of previously unconnected processes in order to improve
overall efficiency by reducing or eliminating redundant
data entry or processing operations, e.g., a billing result
file (data base) containing information from incoming customer orders is used for: inventory (calculated usage),
accounts receivable (generate statements), and sales
analysis applications. Integrated data processing is also
known as management information systems (Ml S).
KEY -

One or more characters used to identify a particular record,
especially used for sorting and merging operatings, e.g.,
an inventory part number and employee number. There may
be multiple key fields in a record; e.g., a salesmen's
commission file may be sorted by salesman within branch,
within district, within region.

MASTER FI LE - A reference file of semi-permanent information which
is usually updated periodically by a transaction file, e.g.,
an employee MASTER FI LE that contains a record for each
employee. Each record would contain an employee number
field, name field, address field, pay rate field, year-to-date
gross pay file, etc. The year-to-date gross pay field would
be updated each pay period.

INTRODUCTION - 4

RECORD - A group of related information items treated as a unit.
A record is divided into one or more fields; e.g., an
inventory record for each commodity might contain the
fol lowing fields:
PRODUCT NUMBER (A FIELD)
DESCRIPTION
NUMBER ON HAND
NUMBER ON ORDER
MINIMUM BALANCE
UNIT COST
NUMBER USED YEAR-TO-DATE
RANDOM ACCESS
FILE - A mass storage device capable of accessing any record
directly without processing al I prior records. A data file
arranged on a randomly generated record address -- access
to a record is accomplished by calculation of a formula
based on a key in record. No index is required for this
type of file.
SEQUENTIAL
FI LE Pertains to a file where records are in ascending or
descending sequential order by an identification key, e.g.,
inventory file sequenced by part number. SEQUENTIAL
FI LES are for batch processing in which the files are on
cards or DECtape. However, disk files may also be
seqi.Jentia1.
TRANSACTION
FI LE Records of data to be processed with master file record in
order to update the master file, e.g., a file containing all
of the daily transactions in an inventory control application,
such as quality of items received, shipped or ordered, which
update the inventory master file reflecting these changes.
A transaction file is also known as a detail file.

COMMERCIAL DATA PROCESSING TERMINOLOGY (cont.)

DIBOL - A PROGRAMMING LANGUAGE

VARIABLE LENGTH
RECORDS - A file containing a set of records in which the number
of characters of each record may vary in length. Usually a
VARIABLE LENGTH RECORD is preceded by the character
count for that record.
As a small business computer with COS, the DDS300 provides
solutions for users with varied business scopes and backgrounds. The
implementation language for COS 300 is DIBOL. A general overview
fol lows to provide the student and/or business manager insight into
those system elements used for program creation.

DIBOL - Dlgital Business Oriented Language - is a general purpose
higher level commercial programming language used by the program mer to implement commercial applications. Its compiler is an integral
part of COS 300. With the COS 300 DIBO L compiler, the system
generates application programs in computer machine language
(MACRO instructions) to run on any DDS 300 computer.
A DIBOL program is divided into two sections, a data definition
section and a procedure section. The data section states (tags) a
data file's record information structure in program operable units. In
the procedure section, the language consists of a select group of
English-like procedural verbs, each with comprehensive arguments.
The verbs: PROC, START, END, ON ERROR, INIT, FINI, INCR,
TRACE, NO TRACE, TRAP, XMIT, READ, WRITE, GO TO, IF,
CALL, RETURN, CHAIN, ACCEPT, DISPLAY, FORMS, and STOP,
plus data manipulation statements, provide the user with easy to use
and powerfu I statements for the development of his programs.
There are eight types of statements:
Compiler Statements which tell the compiler the nature of
the statements to fol low.
Device Control Statements which prepare data files (open
and close) for use by the application program.

Doto Specifico-tion Statements which desc~tbe the type,
size and iocation of data eiements.
Data Manipulation Statements which control calculations
and movement of data within memory.
Data Accept and Display Statements which define the
cursor coordinates used to format data entry and display
on the CRT terminal.

INTRODUCTION - 5

DIBOL - A PROGRAMMING LANGUAGE (cont.)
Control Statements which govern the sequence of execution
of statements within a program.
Input/Output Statements which control data movement
within memory or between memory and peripheral devices.
Debugging Statements which trace program execution during
test runs.

Branching. A computer operation similar to switching, where a
selection is made between two or more possible courses of action
depending on a related fact condition (IF and GO TO statements).
Many Levels of CALL Nesting. Statements which include routines
to cal I other routines.
Tracing. Trace statements may be placed at strategic locations
within a program to provide a usage correlation (source line numbers)
between statement execution and the intended source program logic.

Language Features

Editing. When transferring data, field editing occurs with left and
right justification, padding and "check protect" features.

Simple English-like Procedural Statements. Meaningful expressions
to the user and the system's program compiler (not assembly language).

Cursor Control. Statements which provide display and data entry in
a particular applications format on the CRT Terminal.

ANSCll Character Sub-set (specified by the American National
Standards Institute. ANSCll character code ~sed as a Standard Code
for 0formation ~terchange).

Forms Control. The Forms statement is used to automatically position
business forms to be printed on the DEC DATASYSTEM Line Printer.

Multi-1/0-Level Data Access by File, and Record. Direct access,
at the logical (program) level, to data stored on disk or DECtape.
Data Manipulation via: Record, Field and Subfield. Statements to
clear data fields, move data between fields, convert decimal data
to/from alphanumeric data, and format data, etc.
Arithmetic Expression. Performs division, multiplication, addition,
subtraction, and rounding.
Array Handling. Any part of an array (series of items) can be accessed
in a program statement by Iisting the position of the item. Subscripting
notations (expressions in parentheses) are used to specify items in a
list or table according to DIBO L rules.
File Initialization. Statements assigning specified peripheral Input/
Output channels to logical or physical devices.

INTRODUCTION - 6

COf..AMERC!AL OPERATING SYSTEM
COMPILER

The COS 300 Compiler enables the DIBOL user to compile a source
program utilizing up to 28K word locations of memory (56,000
characters) for his application system. Input for the source program
can originate from the console keyboard, from cards, from DECtape
or disk, and from paper tape. Source program inpur is implemented
via the COS 300 Monitor which provides the user both input editing
and generation of job control statements. The standard output from
compilation resides on the System's mass storage device in executable
format and may be stored by name in a user's program library.
As a mass storage resident system, DIBOL provides the facilities for
random storage and direct retrieval of programs and data on both
DECtape and cartridge disk. The system also provides the abi Iity to
dynamically divide DECtape and disk storage into fifteen logical
units for data file storage.
Each cartridge disk can contain up to 404 directly accessible segments
of 8, 000 bytes each. The COS 300 system handles storage capacities
ranging from 377, 344 character DEC tapes to 3 .2 mill ion character
disk cartridges. This al lows a simple but comprehensive means for new
users to uti Iize state-of-the-art cartridge disk storage for their on-I ine
data base.
At compile time, the minimum configuration required to operate is
the DEC DATASYSTEM Mode1 320 ot1d resident COS 300 software.
At run time the user's applications programs can utilize a wide range
of input/output facilities, full internal capacity, and through-put of
any model in the DDS 300 series. This includes Models 320, 330,
and 340.
Several COS 300 system programs are utilized with the compiler in
the process of creating user programs.

Monitor
COS 300 provides program operation master control via a System
Monitor. To facilitate memory economy the Monitor resides in two
segments: one core resident, and the other residing on the system
device. Together these segments provide the fol lowing facilities
through a comprehensive set of Monitor commands used for:
•
•
•
•

Program Loading,
Editing,
File Directories,
Operation Messages.

The Monitor contains all the system 1/0 handlers required for efficient
throughput and a high degree of program/device independence. The
system provides a specialized software handler for each peripheral
device on the DEC DATASYSTEM.
The assignment of logical units to physical mass storage devices provides greater utilization of the storage area. This device independence
is avai Iable at run time. Any mass storage device can be specified for
1/0 and program execution using the devices specified via SYSGEN.
Editor
Editing consists of a Iine editor as part of the Monitor. It is an
operator/system interactive editor providing a "scratch-pad file 11 for
source program entry. Input statements consist of line numbers fol lowed
by the information to be inserted, deleted or changed. The COS 300
editor provides O\J·tomotic sequencing and resequencing of Iine numbers
by simple commands. Input for the editor can originate from the
console keyboard, cards, paper tape, DECtape, or disk. Output from
the editor can be a Iisting of a file on the console display or the Iine
printer or paper tape. In the program development stage the user can
save and quickly recal I programs from the system device (DECtape or
cartridge disk). In an operational mode, the user can batch commands
to the Monitor into a file to be executed as a job stream.

INTRODUCTION - 7

COMMERCIAL OPERATING SYSTEM (cont.)

BUILD

SYSGEN (SYStem GENeration)
A conversationa I uti Iity program that allows the user to configure or
modify the current system using simple Eng Ii sh-type statements. It
provides the fol lowing optional features:

A file creation program used to create a data file. It is a key-word
data entry package. A BUILD "Control Program" al lows the user to
specify key words fol lowed by an ordered string of formatted data.
BUILD has the fol lowing features:
•
•
•
•
•
•
•

Configures the 1/0 hand Iers in the system,
Takes new logical unit assignments from the
operator's terminal,
Prints a table of current logical unit assignments.
The user can specify the type of Iine printer used and where the
system is to reside, on DECtape or disk. The user can also specify
the number of columns used on the line printer, either 80 or 132
columns. SYSGEN provides the facility to transfer the system to
another device for installation startup.

•
•

Provides hash totaling,
Provides range checking,
Computes check digits,
Provides auto-dup field (automatically duplicates fields),
Permits specification of default fields,
Permits specification of incremental fields,
Checks errors on any one or al I given fields within a key
word line,
Sets special field flags that the user can later check
under program control,
Has the ability to specify up to seven different output
files from one input file.

PIP Peripheral Interchange Program
A utility program which provides file transfer from one device to
another. It will permit the user to move source, binary, system, or
data files from one device to another. It has the fol lowing
capabilities:

BUILD facilitates a way of flagging certain fields within a record
for use as a program control switch.
UPDATE
A master-file maintenance program used to:

•
•

Replaces the old file with a new file
Transfers .Jnpvt from cards-, paper tape, disk, or
DECtape, and Outputs to paper tape, DECtape,
disk or the line printer
Copies an entire DECtape or disk onto a similar device
Eliminates overhead space from the file directory.

•
•
•
•

Change existing· records on the data file,
Insert new records,
Delete old records,
Print a report showing al I changes, inserts and deletions.

SORT
Date File Creation and Maintenance Programs
System programs avai Iable for structuring transaction files are:
BUILD, .UPDATE, and SORT. For more detailed information concerning this software, refer to the COS 300 System Reference Manual.

COS 300 SORT is a poly-phase sort. It can sort data file records in
ascending and descending order. SORT requires a minimum of three
DECtape units or an equivalent disk unit. The user can specify up to
eight fields (with sub-fields) of a fixed length record cs a sort key.

INTRODUCTION - 8

COMMERCIAL OPERATING SYSTEM (cont.)
The SORT has a merge file capability. For a multi-reel sort, each
file must be sorted then merged. The same SORT control program may
be used for both sorting and merging.

PATCH
PATCH is used to fix (or patch) system programs or the Monitor on a
COS system tape. Data to make the changes is provided by DEC as
patches in the form of a dialog.

Uti Iity Programs
Several utility programs are provided, among which are the following:
CREF, DAFT, MARK, BOOT, and PATCH.
CREF
CREF is a cross reference utility program to aid program development.
It provides an alphabetical listing of all symbols used in a DIBOL
program, along with the line number where each symbol is defined
and used.
DAFT
The DAFT (Dump And Fix Technique) program provides the capabi Iity
to search
examinecmd change records as we!! as to !ist records
and parts of records on the line printer or terminal.

for,

MARK
There are four format programs, RKEMRK, RK8MRK, TDMARK, and
DTMARK, which are used to mark DECtape and disk for use with the

cos 300.
BOOT

BOOT is used to bootstrap the system from one device to another.
For exampie, BOOT is run to transfer control from DECtape to disk
so that the latter may become the system device.

INTRODUCTION - 9

DIBOL

MANUAL AND SYSTEM CONVENTIONS

SOURCE LANGUAGE INPUT

artridge
Disk

Keyboard

Several documentation symbols and terms used in this text are
described belowPaper Tape

Lower-case characters - Represent information that must be supplied
by the user, such as values, names and other parameters.
Upper-case characters - Words or characters that must be used
exactly as shown.

SYSTEM
Monitor

System Device
\

OB
I

DIBOL
COMPiler

System Device

Symbols

El Ii psis ••• - Indicates the optional repeating of the preceding data.
Underscored characters - Indicate output from the system.
(Space) - Indicates a space.
I

~--39ol

Compilation
Diagnostics
Printed
Listing

,OB)

{)

(Braces) -

(Brackets) - Brackets indicate an optional feature.

)

(CR Key) - The down-arrow indicates a Carriage Return Key
operation on the terminal keyboard. At this
point, control is advanced to the next line.

Braces indicate a choice of one of the items
enclosed.

Terms

"V"

Object Program Files

System
Diagnostics

file-name, program-name, label and keyword - are used to identify
names assigned to files, programs, statements, and input lines.
These names may be of any length, but only the first 6 characters are recognized.

OBJECT
PROGRAM
EXECUTION

cursor - An underscore symbol on the operator's display screen which
indicates the character position for the next keyboard stroke.

Applications
I/O

INTRODUCTION - l 0

SECTION 1
Basic Source Language Programming

1-1

This chapter is intended to give the student a frame of reference in
the form of an overview of DIBO L programming and operation.

QUESTION:

(

In the fol lowing frames you will learn, through programmed instruction, how to read a simple DIBO L program. The questions will be
based on program examples which provide frame answers.
Frame one presents a program statement of what the first example
program does. (Turn to Foldout #1). Read the program definition
and review the foldout before proceeding to the QUESTION and
ANSWER.

PROGRAM: Information is stored in records located on a DECtape.
Each record is to contain 64 characters. A read
operation reads one record at a time (starting with the
first record in the file). List on the line printer all
information on the DECtape file, printing one record
on each line. After printing the last record on the
tape file, stop the program.

ANSWER:

***
It denotes the beginning/end of the program
logic flow.

QUESTION:

What is the function of th is symbol?

ANSWER:

It denotes the testing of a condition and,
depending upon the outcome of the test, shows
the action to be taken.

4. QUESTION:
Systems and program flow charting is a technique used in organizing
and documenting information about existing application systems and
in planning new ones. Diagrams called flowcharts show the flow of
information and the sequence of operation. They are important
items in evaluating procedural logic and useful tools for future
program expansion and revision.

1. · QUESTION:

ANSWER:

Does-theHowchort onfofdout·#+ Hlustrate the
logic outlined in the verbal statement of our
program?

***
ANSWER:

__)

What is the function of this symbol?

Yes, the flowchart is accurate.
The shapes of the boxes in the flowchart denote
different functions such as comparison, reading/
writing, beginning/end., and internal data arrangement. Using the flowchart, answer the questions:

1-2

What is the function of this symbol?

***
It denotes an Input (reading) or an Output
(writing) operation to be performed by the
computer. (In the program there is an internal
·· aev1ee-cfssignmE'frff so lhe ·computer would issue
a read/write command to the proper input/
output device.)

QUESTION:

What is the function denoted by th is symbol?

ANSWER:

QUESTION:

***
It denotes explicit commands·such as device
initialization, move data, etc.

***

Below the flowchart on Foldout #1 is the DIBOL-coded program which
accompiishes the functions diagrammed. Note that it requires oniy
ten statements to accomplish the out I ined task.

ANSWER:

Statement 3; (FIELDl, A64).

QUESTiON:

Statement number 3 says the biock of storage
labelled FIELDl will be reserved for 64 alphanumeric (A) characters. What is FiELDi?

The following dialogue is designed to help the reader understand the
function of each statement in the DIBO L program.

QUESTiO N:

***
ANSWER:

It is a field label. It could just as well be
cal led XX, YY, or any six character field beginning with a letter. it serves as a symboiic
name which the programmer can reference from
the procedure section of the program (note: it
is referenced in the sample program via the
record 1 s label). One or more field statements
is required for each RECORD statement.

10. QUESTION:

The RECORD statement (#2) gives a label
11
NAME 11 to an area of computer memory available for record input. If several different input
devices are being used, several different
RECORD statements (with their respective fielddefin!tion statements following) could appear.
In order to designate two 16 alphanumeric character fields and one 32 alphanumeric character
field instead of the present 64-character field,
write the appropriate RECORD and fielddefinition statements.

From the flowchart, is each character of information passed directly from the DECtape to
the printer?
***

ANSWER:

QUESTION:

No. A complete record composed of 64 characters is read into the computer memory before
any data is written (output) on the line printer.

Since data records are not restricted in length to

64 characters, how does the computer know how
much memory to reserve for the storage of the
data record?
***
ANSWER:

The programmer must tei I the computer how much
memory wi II be required to store input data. A
DIBOL RECORD (or BLOCK) statement reserves
areas of core to be used during processing and as
temporary storage (input/output buffers).

In a program the area of memory reserved for
record storage precedes the processing instructions. From the DIBO L coding on Foldout #1,
which statement al locates 64 characters of
storage?

I
1-3

***

ANSWER:

11 •

QUESTION:

13.

RECORD NAME2
FIELDl, Al6
FIELD2, Al 6
FIELD3, A32

QUESTION:

Which statements are actual processing instructions?

***

A compiler control statement is a non-executable
DIBOL statement. Such a statement gives the
compi Iing program information necessary to
properly interpret notations made by the programmer. Compiler statements tell the compiler
program when to begin and end encoding DIBOL
source statements, and when to begin converting
DIBOL statements into actual machine procedures.
Look at the sample DIBO L program and determine
which are the compiler statements.

14.

ANSWER:

Statements 5 through 9 are processing statements.

QUESTION:

What is the function of the word LOOP in
statement 8?

***
ANSWER:

LOOP is a label denoting a point in the processing cycle to which the program branches.
In this case, the program branches to statement 6.

QUESTION:

Statement 5 is the first processing instruction.
From the flowchart, what is accomplished by
th is statement?

***
ANSWER:

Statements l , 4, and l 0. Statements l and l 0
tel I the program the bounds of the DIBO L coding.
Statement 4 tells the compiler program to interpret the following lines of coding as procedure
to be executed by the computer.

15.

***
ANSWER:

12.

QUESTION:

The data section of a DIBO L program describes
the data elements used in the program and
allocates memory. Which statements -i-n
Foldout #1 comprise the data section?

***
ANSWER:

It tells the computer which channel number
wi 11 be used (whenever the program refers to
this file, its channel number will be 2);
whether the file will be read (Input) or written
(Output), the-name of the file (F-ILEl} / GRd
where the file could be found (logical unit 1 ).
This process is called file-initialization.

Statements 2 and 3 comprise the data section.
Depending on the logical unit assignments made through program
SYSGEN, FILEl could be on DECtape or disk.

1-4

16.

QUESTION:

From the flowchart {and following the INIT
statement in the program), what does the XMiT
statement (#6) do?

19.

QUESTION:

***
ANSWER:

It causes a read operation from channel 2. The
XMIT refers to data transmission. It can either
read (IN) or write (OUT) depending upon the
file-initialization. If a file is initialized as an
input (IN), the XMIT statement would cause a
I
••
,.
I
,.. I I,.
reaa operanon rrom me rt 1e. ir a rt 1e 1s
initialized as an output (OUT), the XMIT
statement wouid cause a write operation onto
the file. The data is either read from, or
written into, the RECORD specified in the
XMIT statement (in this example, RECORD
NAME).
I

["~I

***

ANSWER:

QUESTION:

must be a write command (writing data from
storage RECORD NAME to channel number 6).

QUESTION:

For XMIT (2, NAME) to cause a record to be
written, what would the initialization state-

ment look like?
***
ANSWER:

QUESTION:

For XMIT (2, NAME, ENDFIL) to cause a
record to be read, what would the initialization
statement look like?

No. It is a line printer and therefore does not
need initialization.

If not specified, the fol lowing channel number associations are
assumed by default:

***
ANSWER:

Note that it is necessary to initialize only a
file-oriented device such as DECtape or disk.
Devices such as terminal, line printers, cards,
and paper tape readers do not need initialization. Is device specified by channel number 6
a file-oriented device?

***

INIT (2, Output, file-name, unit)
ANSWER:

18.

Since there is no end-of-file pointer (just a
-'--------' ___ --'---· _____ , •-'-- nl:'.'r'"'n~ •--'--" '-'-~c;nanne1 numoer ana rne f\l:'-Vru.1 1aoe1 J rr115

20.

17.

Statement 6 says: Read a record from channel
number 2, storing the data from that record in
the area labeled NAME. When no more
records are available, i.e., the end-of-file
(EOF) has been reached, then jump to the
instruction labeled ENDF IL. Noting that
only READ instructions have pointers to which
the program will branch when an EOF is
reached, what does statement 7 do?

INIT (2, Input, file-name, unit). (As in
statement 5 in our example.)

1-5

paper tape reader
i ine printer
keyboard
terminal scope or printer

21.

QUESTION:

25.

What does statement 8 do?

QUESTION:

***

22.

ANSWER:

It is an unconditional command for the computer
to branch to the instruction labeled LOOP.

QUESTION:

What is ENDFIL?

Below is the same flowchart diagram as listed
on the foldout. Mark in the appropriate
statement number corresponding to the flowchart function.

PROC

***

23.

ANSWER:

It is the label for the end-of-file routine
referenced in statement 6. This label indicates
the location for program transfer at the end of
the input file. In this example, program control would transfer to statement 9.

QUESTION:

What seems to be the function of statement 9?

***
ANSWER:

It is a FINlsh statement with respect to the file
on channel 2. Actually, in an output file, an
end-of-file mark would be put on the tape, the
tape would be rewound, and the channel number
freed for other use. In the case of our input
file, the channel number is freed but the file
is not rewound. Only file-oriented devices
r~quire a FINI statement.

***

24.

QUESTION:

Why was channel 6 not issued a FINI command?

ANSWER:

***
ANSWER:

It is not a file-oriented device. The only fileoriented devices on a DIBO L configuration are
DECtape and disk.

A=5
B=6
C=9
D=7
E=8

F =10

1-6

COS 300 DIBOL CODING FORM
PROGRAM TITLE

REQUESTED BY

PAGE

PROGRAMMER

DATE

PROJECT ID

FOLDOUT tq

SAMPLE PROBLEM
FLOWCHART
PROC

INITIALIZE
DECTAPE
AS INPUT

! !

~l I

' ,

b:.

! ..1.

I l
:

FILE~

1T I

l l

l !

THE PRINTER

DIBOL PROGRAM FOR PROBLEM
l

····i

l
l
I

l
I

I
I
I

~
r+-1
1-+-1

~
,

J_
I

I I

lll

I II

_Ll

j_J_

J.'

__,_':

Statement Numbers

.·

_l_

START
RECORD NAME
FIELDl I A64
PROC
INIT (2, IN,aFILE' I 1)
LOOP, XMIT (2, NAME, ENDFIL)

XMiT (6, NAME)

3 1•

ENDFIL,
END

516 7 II

DEC 7 -(30Z) - 1134 • N17Z

1-7

GO TO LOOP
FINI (2)

;l COMMENTS

;2
;3
;4
;5
;6
;7
;8
;9
;10

SUMMARY
Sample Problem

To review the initial problem, i.e., printing a 64 character record
from a tape file onto a line printer until the end-of-file, examine
the following lines of the DIBOL program:
START

;Compiler statement, non-executable.

RECORD NAME

;Indicates the beginning of the contiguous area for the data elements
that comprise RECORD NAME.

FIELDl I

;Data statement FIELDl is an alphanumeric field 64 characters long.

A64

PROC

INIT (2, IN,
FILEl 1 ,1)

LOOP,XMIT
(2, NAME, ENDFIL)

;Compiler statement - begins procedure section.
;Initialize channel 2 as an input file.
The lohel of the file is FILEl and it
can i::)e found on logical unit l •
;Read a record from channel 2 into the
area assigned to RECORD NAME.
When end-of-file is reached, it
causes-a program transferto·ENDF-ll.

XMIT (6, NAME)

;Write RECORD NAME onto channel
6 (I ine printer).

GO TO LOOP

;Go to statement that reads another
record.

ENDFI L, FIN I (2)

;end-of-fl Ie.

END

;Compiler statement--indicates the
end of program.

1-8

FOLDOUT #2
Basic Operating Steps

BASIC OPERATING STEPS

In addition the operator must enter the current date before proceeding. This date is used during program execution to date
reports, files, and new programs.

There are several fundamental operating steps required to convert
your documented program logic into machine usable binary code.
Using a properly activated (powered-up) DEC DATASYSTEM Computer,
you must first load the central processor's memory with the COS 300
Monitor program. This system initialization is activated by the
Hardware Bootstrap Switch, but only after you have correctly insta! led the System DECtape or Disk Cartridge on the drive addressed
as zero. Refer to steps land 2 in Figure 1-1. This figure presents
the basic operating steps as: major operating categories: an operational flow diagram, and specific operating steps (l -1 O). The major
operating categories are as fol lows:

Review step 5 in Figure 1-1 • The Monitor provides editing commands
to input and manipulate Source Program statements in a temporary
storage area (edit buffer) within memory. They include:
Number commands - inserts the text line beginning with
the number into the edit buffer {line number text).

Erase (ER) - erases text from the edit buffer.
Resequence (RE) - renumbers the program Iines to adjust
for additions and deletions.

ANSWER:

Steps l and 2 load the System Monitor.

Hardware
BOOTSTRAP
1-4

2.
3.

Keyed data input
Source
Input

corrections

, s.

Source Program
creation - using
DIBOL language rules
5

Compile Source Program
into Object Program
and print diagnostics

All text input to the Monitor must be assigned a series of line numbers
All inserts, changes, and deletions are accomplished using these
numbers.

QUESTION:

COMP

To compile the completed progra..u in
the editor scratch area enter:

Check the source listing generated by
the compiler for error messages. A

.RUN COMP)

Source Program

caret (A) points to the error.

evaluation

ANSWER:

***

The ERASE command, when used without Iine
numbers 1 clears the entire edit buffer. This
prevents unused buffer lines, containing lines
from a previous program, from appearing as
part of the current program.

To run the compiler program if no
errors are detected enter:
.RUN)

Program File Creation
9.
Store the Object

Program on the
System device

SAVE
Completed
bject Program
9

Store the Source
Program on the
System device

To save the object program under a
unique program name enter:
. SAVE prognm )

10. To save the source program from the
editor scratch area for future
modification enter:
.WRITE prognm)

WRITE

ource Program
as Backup
10

Figure 1-1

1-9

Use

the Editor functions to correct all
language errors and then recompile.

Using Figure 1-1, which of the above commands
is used as a prerequisite to program text entry?

***

After the system responds on a new
line with an initial period (_J , enter
a DIBOL prcgra.~ putting one statement
on a line. Precede each statement
with a line number and a space. To
correct a statement, type its line
number, a space, and the new statement.

Compile Source Program

Program logic test

27.

Mount the proper System DECtape or
Disk Cartridge.
Press the bootstrap switch.
The Computer responds with DATE?
The operator enters the month/day/year
in the following statement.
.DATE L..1mm/dd/yy)
After the system
responds on a new line with an initial
period (.) enter ERASE) to clear the
Edit Buffer.

Editor Source Input

Language

The Monitor routine must be loaded via a bootstrap operation. This is
an internal computer hardware/software technique designed to bring
itself into a desired state of readiness by means of its own action,
e.g., a hardware initiated routine whose first few insfructions are
sufficient to bring the rest of itself into the computer from either the
DECtape or disk storage device.

From Figure 1-1, what operator step or steps are
necessary to accomplish this initialization?

1.
System Initialization

Line Number (LN) - automaticalty outputs Iine numbers
so new programs can be entered without typing each line
number.

Study Figure 1-1 and then answer the following questions.

QUESTION:

System Initialization

System initialization,
Keyboard input,
Source program editing,
Source program compilation,
Source program syntax evaluation and correction,
Program logic testing and correction,
Object program storage,
Source program storage.

26.

NOTE

To compile the completed program use the Monitor command statement RU 1....1COMP) •

of the DIBOL language syntax is correct. It does not guarantee
that the logic of your program will produce the desired results. The
only way to test your program logic properly is to run the compiled
program with real or simulated data.

The compiler takes the DIBO L language program from the edit buffer
and converts it to an object program which can be executed by the
computer. In the process of creating the executable program the
compiler can generate a printed listing of the source program and a
storage map of the records and fields which are used by the program.

To run the compiled program, enter the Monitor command RUN) •
When a file-name is not given after RUN, the binary file (compiled
source program) in the Edit Buffer is used as input to be executed.

The compiler checks the source program for DIBOL syntax errors. The
source program must be free of these errors before object program code
can be generated.

29.

Most compiler error messages are printed on the source listing after
the line in which the error occurs. A caret (") in the source line
points to the approximate location of the error. A complete list of
errors can be found in the COS 300 System Reference Manual.
Several commonly found messages follow:

QUESTION:

ANSWER:

First make the necessary adjustment to the
program documentation then steps 5, 6, 7 and
8 must be repeated to change the program •

The Monitor allows both the binary file (B) and source file (S) to be
assigned the same name. To protect both versions of the completed
program, you just assign it a unique program name and transfer the
edit buffer to a storage device before a new program is entered. This
is accomplished by two Monitor commands, SAVE and WRITE.

From Figure 1-1, when an error message occurs
-at step---7-;--what steps must be taken to correct
it?

30.

QUESTION:

***
ANSWER:

From Figure 1-1, when the program fails to
perform properly with test parameters what
steps must be taken to modify it?

***

UNDEFINED NAME
NAME PREVIOUSLY DEFINED
BAD ALPHA VALUE
BAD DECIMAL VALUE
COMMA MISSING

28.

QUESTION:

Ffom Figure l-1 whkh of the above mentioned
Monitor commands is used to save the compiled
binary program?

***

Steps 5, 6 and 7 in Figure 1-1 must be repeated
to correct the error. You should correct all
known errors before step 6.

ANSWER:

The SAVE command stores the finished version
of the object program on the System storage
device under a unique program name.

The COMPiler will signal a clean listing with the message "NO
ERRORS DETECTED" on the print-out. This indicates that your usage

1-10
JI

SECTION 2
DIBOL Syntax

The student should now have a general knowledge of the elements
that make up a DIBO L-coded program, thus making the information
in this section more meaningful.

2-1

DATA SECTION

START
PROC
END

There are three kinds of statements in a DIBOL program:
1•
2.
3.

There are two sections in a DIBO L program. First is the data section
which describes all data and causes allocation of memory storage.
Second, there is the processing section which contains the executable
instructions.

QUESTION:

DIBO L programs normally consist of a START statement, fol lowed by
the data section {composed of data statements), followed by a
required PROC statement (a compiler statement), followed by the
procedure section (composed of procedure statements), fol lowed by
an END statement. START and END are optional statements.

What is the statement that separates the data
section from the processing section?

***
ANSWER:

Compiler statements.
Data statements.
Procedure statements.

QUESTION:

The PROC statement.

What is the only required compiler instruction
in a DIBOL program?

***
2.

QUESTION:

Is PROC an executable statement? If not,
what is it?

***
ANSWER:

ANSWER:

PROC

QUESTION:

What are the three compiler statements and
two sections that make up a DIBOL sourceprogram (in the order in which they appear)?

PROC is not an executable statement. From
the previous section we recognize it as a
compiler statement.

***
ANSWER:

QUESTION:

(compiler instruction)
_data__secH on_

PROC

***
ANSWER:

START

V{hat is a cornpIJ~r st(lt~!11-~-~-f?

A compiler statement is a message to the
compiler program indicating the nature of the
DIBOL-language statements. A compiler
instruction is not executable by the DIBOL
program.

END

(compiler instruction)
processing section
(compiler instruction)
RECORD

QUESTION:

Where is the data section in a DIBOL program?

***
ANSWER:

2-2

The data section is between the ST ART and
PROC statements.

QUESTION:

From the sample program, in which section does
the RECORD statement ieside?

ANSWER:

The RECORD statement resides in the data
section.

area, or the contents of this area may be written (output). There is
no punctuation between a RECORD statement and its name (if a
name is required).

***

QUESTION:

What can be deduced about the second
RECORD statement fol lowing?

The RECORD statement designates the beginning of a group of data
statements. It may or may not give that group a name. It controls
where in memory the block of data will be stored. A RECORD
statement must be foi iowed by one or more data statements. (A data
statement defines all data elements with respect to type and size.)
The word BLOCK may be used interchangeably with RECORD. The
general format for a RECORD statement is:

START
RECORD A
A 1

M.I /

A2, Dl
ncr"n""'

f\L'-Vf\LJ

Bl, D3
PROC

RECORD
required

record-name,
optional

QUESTION:

In the following example, is the RECORD
statement used correctly?

***

optional

ANSWER:

START
RECORD A
RECORD B
Bl, A6
PROC

Since the second RECORD statement does not
have a name, it is not intended to be used as
on input/output buffer. It is used only for
temporary storage of program data.

The data statement is used to define al I data elements with respect
to type and size. The DIBO L compiler assigns storage for the data
on the basis of these statements. Any data statement that fol lows a
record name is assigned to the contiguous memory locations in the
order that the element occurs. If a record name is missing, the
succeeding data statements are assigned to contiguous locations but
not associated with any record name for input/output. If such data
statements are referenced, they are done so individually.

***
ANSV/ER:

A L

1-\0

RECORD A is an invalid statement because a
RECORD statement must be followed by one or
more data statements. RECORD B is used
correctly.

The general format of the data statement is:
data name,
optional

A block of data requires a name only when referenced by an XMIT
(data transfer) statement. A record may be read and stored in this

2-3

data specification,
required

initialization-specif.
optional

The data name is optional, that is, a comma may be used without a
data name if the program does not reference that individual data
element but only references the entire RECORD. This is convenient
when formatting an output Iine for the printer, so that intercolumn
spaces do not require a data name but merely a comma followed by
the type and size, e.g., (,A5). Normally, the data name is used,
followed by the data specification (type and size), with an optional
initialization field.

l 0.

QUESTION:

In the fol lowing statement, what are the
fields?
TOT, 06, 000012

***
ANSWER:

The initialization-specification would normally be used in the
temporary storage record but could also be used in an output record.
If a specific data element is to be referenced, it must have a data
name.

TOT is the name by means of which the data
can be referred; 06 is the data specification
(in this case, six decimal digits) and 000012
is the initialization specification (setting the
six decimal digits to an initial value of 12).

The data specification field (which fol lows the data name) consists
of a data type (Alpha or Decimal), and the data size in characters.
If the data size is omitted, l is assumed. If the initialization
specification is present, the data specification is followed by a
comma, then an alphanumeric or decimal constant. The alphanumeric may contain any legal character enclosed in apostrophes.
The decimal constant is a string of digits, optionally preceded by
a plus or a minus sign. The plus sign is implied and the minus sign
does not require a character for storage; i.e., NUM, 05, -12345.
Data types cannot be mixed. For example, an alphanumeric
constant may not be assigned to a decimal variable. The data
element is assigned to the value of the initialization specification
at the beginning of program execution. If the initialization
specification is omitted, an alpha field is set to spaces and a
decimal field to zeroes.

Following are examples of valid data statements:
A, AlO
A, A7,'DIGITAL'
A, 06, 123456
FISH' A4, 'FISH I
, A5
COST, 506
NOTE
The Data element COST consists of 506, which
means there is an array of five fields, each six
digits long. This could have been_ written as:
COSTl, 06
COST2, 06
COST3, 06
COST4, 06
COST5, 06

11.

QUESTION:

Describe the data specified for the following
five items:
a)
b)
c)
d)
e)

(The referencing of COST, 506, is done with
subscripts which wil I be defined in the procedure
section.)

A,
TOT,
NUMS,
HORS,
TABLE,

***

2-4

AlO
06
1003
10Al2
3 02' l 3, l 5' l 8

ANSWER:

a)
b)
c)

, "I

I L. •

QUESTION:

A is an alphanumeric element with ten
characters having a vaiue of spaces.
TOT is a decimal element with six digits
having a value of zero.
NUMS is an array of ten decimal numbers,
each with three digits having a value of
zero.
H DRS is an array of ten alphanumeric
elements, each with 12 characters having
a va I ue of spaces.
TABLE is an array of 3 decimal numbers,
each with two digits. The first element
has a value of 13, the second a value of
15, and the third a value of 18.

There are three ways data items can be initialized in the Dato
Section.

Suppose you want to reserve, in computer
memory, a place to store a record with four
fields to be described as follows: F LDl has
three alpha characters, FLD2 has six decimal
digits, FLD3 has four decimal digits set to the
value 125, and FLD4 has 10 alpha characters
set equal to the name DIG IT AL. Write the
appropriate RECORD and data specifications
for this input buffer.

A Data statement containing a P.

A Data statement containing a D.

A Data statement containing an initialization specification
value (previously discussed).

DATE,A8, P
Upon loading the program, the following message would type out on
the console:
ENTER DATE

RECORD IN (any name will do)
FLD1,A3
FLD2,D6
F LD3, D4, 0125
FLD4,Al0, 'DIGITAL L....U • ...IL-1

One way of initializing a data item is by putting a P immediately
after the data specification field of a data statement. Upon loading
the program, the computer wi 11 ask the operator (via the terminal)
to enter the value he wants to give that data item. A common use
of this feature is to obtain a report date which differs from today's
date in Monitor. For example, the data statement might be
described as:

***
ANSWER:

P OPTiON

At this point the program wou Id wait for the operator to type in
eight characters and type carriage return. The operator might type
in 07/07/72 and type carriage return. CAUTION: If less than
eight characters were entered, the results would be stored leffjustified in DATE. If DATE were a decimal field, the results would
also be stored left-justified. Unentered characters are either zero
or spaces, de pending upon the fie Id type. Too many characters
wou Id run over into the following fields. For decimal fields, there
is no verification that the characters entered were decimal
characters.

2-5

13.

QUESTION:

Suppose the programmer wanted a three-digit
customer-number to be supplied by the operator
at the beginning of the run. Write a data
statement to initialize a field named CUST.

INITIALIZATION-SPECIFICATION
A third way to set the value of a data item is by using the initial ization option, i.e., specifying an alphanumeric or decimal constant.
The alphanumeric may contain any legal characters enclosed in
apostrophes. The decimal constant is a string of digits, optionally
preceded or fol lowed by a plus or a minus sign, but without apostrophes. Data types cannot be mixed in that an alphanumeric
constant (i.e., DEC, D3). But 1 004 1 can be assigned to an A3
alphanumeric field.

***
ANSWER:

CUST ,D3,P

Ordinarily, input from the keyboard must be described in alpha
format. This restriction does not hold true for initialization data (P).

15.

QUESTION:

Are any of the following statements incorrect?

D OPTION
a)
b)
c)
d)
e)
f)

A second way of initializing a data item is by putting a D immediately
after the data specification field of a data statement. When the program is run, today's date (as s·pecified to the Monitor at start up) is
automatically stored in any field having a D in its data field specification. For example, the statement might be described as:

***

TODAY, D6, D
ANSWER:
The date in Monitor would automatically be stored in the form
MO DAYR.

14.

QUESTION:

a)
b)

Statement b is incorrect because an alphanumeric notation (an apostrophe) was used to
enclose a decimal item.
(c) is incorrect because a decimal notation was
used to cleSGr-ibe on ol-phenumeric constant.

Write a data statement to initializ~ a fielq
named RNbATE to the date stored in
Monitor.

(e) is incorrect because 23A is not a val id
decimal number.

What would RNDATE contain at run time if
an operator previously entered July 4, 1972
as the Monitor date?

State men ts a, d, and f are correct •

***
ANSWER:

A,A8, 1 ABCDEF98 1
TOT,D3, 1 123 1
NUM,A3, 123
BI D6 I 222334
C, D3,23A
D, D3,456-

When an initialized value is specified in a data statement, its length
must correspond to the length of its respective data statement, for
example, NUM, D4,0070. It would be illegal to initialize NUM to

RNDATE, D6, D
070472

2-6

i 8.

70 since NUM was defined as a D4 field. The initialization specification does not insert leading or trailing bianks (zeros). DiBOL wiii
not permit the size of the initialized value to differ from the data
field size.

QUESTiON:

What information is generated by this data
specification ?
B, D6, 000013

***
16.

QUESTION:

Which data statements are incorrect?
a)
b)
c)
d)
e)

Al ,A8, 'ABCDEF641'
COST I D4,7779
QTY,D5, 1 i0000 1
NUM, D7, 59796
Bi , A4, : 198T

19.

ANSWER:

000013. The initialized value must be the
same length as the data size. In this case,
B is defined as a six-decimal digit.

QUESTION:

What information is generated by this data
specification?

***
ANSWER:

TOT I Dl ,C8

Statement a is incorrect because the initialized
value is longer than the data field.

***
ANSWER:

Statement c is incorrect because apostrophes
are used to enclose a decimal item {apostrophes
are an alphanumeric notation).
Statement d is incorrect because the initialized
value is too short; NUM is defined as a 7-digit
decimal field.

NOTE

!n prior versions of DIBOL, a blank data specification field left the
original contents of memory in a field. To clear the fields of a
record, RECORD C had to be specified. In order to be compatible
with existing programs DIBOL treats RECORD or RECORD C
identically. For example:

Statements b and e are correct usage of the
initia I ization specification.

17.

QUESTION:

We want NUMS to be an array of two decimal
numbers, of three characters each. The two
numbers are to have constant values of 333 and
minus 61 respectively. What is the appropriate
data specification?

RECORD A,C
NU~i,, 06

TOT, D7
COST I D4, 4999
Bl ,A7

***
ANSWER:

None, the value is too long (2 characters) and
C is not a decimal digit. Non-digit characters,
whether or not enclosed in apostrophes, cannot
be used for a dee i ma 11 y defined i tern •

NUMS,203, 333,061

2-7

In this example, the fields in RECORD B occupy the same area of
computer memory as the fields in RECORD A.

The initialized value of COST would not be cleared,
but NUM, TOT, and Bl memory locations would be
cleared. The first statement could have been
RECORD A.

21 •
20.

QUESTION:

Consider the following operation:

What is the value of data labeled Bl?
***

DATE,A8, P
When the program is loaded, the computer
types

22.

ANSWER:

Bl='DIBOL'

QUESTION:

What is the value of B2?

ANSWER:

B2= 1SOFTWARE 1

***

ENTER DATE
and the operator types 07/07/1970. What
happens?

As a general rule, data specifications in overlays should be consistent. Problems may arise if an alphanumeric item is redefined as
decimal in an overlay specification. Normally, initialized values
ore not used in overlays. The overlay (X) block must be equal to or
smaller than the last non-overlayed record.

***

ANSWER:

Since too many characters were typed, it is an
error. 07/07/19 is stored in DATE and 70 is
stored in the fol lowing field.
RECORD,X

23.

The concept of the overlay is a valuable tool in the preservation of
computer memory. By means of the overlay, two RECORD statements
can describe exactly the same area of computer memory. Whenever
there is an X there must be a previously defined RECOR!) st(]t~ment
without an X. Tl1ere can be one or more overiays defining the same
area. Note the use of X below.
RECORD

RECORD

QUESTION:

Is the fol lowing correct?
RECORD

RECORD
RECORD

A
Al ,A5, 1 DIBO L1
A2,A8, 1SOFTWARE 1
A3,A7
B,X
B1,A5
B2,A8
B3,A7 1 SYSTEM 1

***

2-8

A
Al, Dl 0
A;2;Al0
B,X
Bl, D5
C,X
Cl, D3
C2,D7
C3,A5
C4,A5

ANSWER:

Yes. The redefined records, RECORD Band C,
are the same size or sma11er man rne recora
they redefine, RECORD A.
e

. I

24.

QUESTION:

I I

• I

• (

26.

QUESTiON:

in the foiiowing example, determine any errors
in data or record names, in their size or their
value assignment:

a)
b)
c)
d)
e)
f)
g)
h)

Is the following a legal use of the overlay?
RECORD

RECORD

A
Al ,A3, 1FUN 1
A2,A5, 1LOVER1
0

D1 A

Bl I DB

•\
IJ

***
ANSWER:

i)
k)
I)

Yes. However, since Bl is decimal, and the
data it redefines is alphanumeric, a run time
error would occur if Bl were not cleared before
being used in a data manipulation statement.

QUESTION:

TEMP,D

wORKTAB

I
200D6
TABLElO, lOODlO

The record name INPUTBUFFER is more
than six characters and is thus recognized
as INPUTB. This, however, is not an
error.

No errors •

The field name POPULATION is more than
six characters and will be recognized as
POPULA. This is not an error. However,
it is defined as a Decimal field containing
17 digits -- decimal fields used in arithmetic operations cannot exceed l 5 digits
and wi II generate run-time errors.

No errors.

The field name 3ABC is in val id. It must
start with an alphabetic character.

Is it legal to name a RECORD X?

***
ANSWER:

nrrl""\nl"'\
l\C:\.. V l\L.J

***
ANSWER:

25.

RECORD iNPUTBUFFER
NAME,A20
POPULATION,D17
A12Y4X,A21, 1ELKJAOUNTAIN,L-.JWYOMINC
3ABC,A3, 'ABC'
RECORD B
TABLE, 10005
TABLEl I l OD2

Yes. It is also legal to have RECORD X,X.

A symbol (be it a data name, record name, or a statement label
defined in the PROC section) consists of alphanumeric characters, the
first of which must be a letter. Only the first six characters are
significant. Anything in excess of six characters is ignored. Data
names and statement labels must be followed by a comma. A record
that is to be used for input or output has a maximum size of 510
characters. Other records have a maximum size of 4094. A decimal
field has a maximum iength of 15 digits and cannot have a name.
Alphanumeric fields have no size restriction other than record size.

2-9

No errors.

Th is record contains 520 characters. It is
an error to give a record a name if it
contains more than 519 characters.

27.

QUESTION:

,x
***
ANSWER:

No errors. This record is less than 4096
characters. Since it has no name, it can
never be used for input or output.

No errors. TEMP is defined as a Decimal
field containing one digit.

No errors. The field name is recognized
as WORKTA.

No errors. TABLEl 0 is recognized as
TABLEl.

What are the functions of these computerdefined symbols?

The X indicates one record of data elements
will overlay the previous record (use the same
space in computer memory that the previous
record was using); multiple overlays of the
same record are permitted. The semicolon
indicates the beginning of a comment.

If the X option is used in a RECORD statement without a record
name, then a comma must follow the word RECORD, i.e.,
RECORD,X.

Many times a programmer will make comments, so that someone else
reading his program will know what he is doing. A semi-colon {;)
tells the compiler-program that all information following is not to be
interpreted as program text, but rather as comments by the programmer.
Thus., comments can appear on a program listing, but will not affect
th~_op~ra_tie>n of th~_ program~ HerEl is an exomple of q comment:
START
;THIS PROGRAM READS INDIVIDUAL TRANSACTIONS
RECORD A;THIS IS THE INPUT RECORD B_UFFER
Al ,A16;CUSTOMER'S NAME IS STORED HERE
The comment is terminated by a carriage-return line feed. The
comment fol lowing a START or PROC statement is used as a heading
for program I istings.

2-10

DAiA SECiiON SUMMARY

Three ways to initialize data elements in the Data Section:
Data Statement Initialization -

The data section describes all data used in a program and causes
allocation of memory storage. It consists of one or more data
records. Each data record section is made up of a RECORD statement
fol lowed by one or more data statements.
l.

RECORD STATEMENT

Operator Initialization - A data statement with a , P
which al lows entry of data
from console ..

Normal Form ~RECORD record name, "",.,
... ·~., RECORD
INBUF. Al I uninitialized fields are

-•-----'

Date !nitia!ization - A data statement with a , D which
automatically enters Monitor's date
at run time.

~ll::Ull::Ue

Unnamed Form - A record name may be omitted, e.g.,
RECORD. All uninitialized fields
are cleared.

Data Overlay - Overlay a preceding storage area,
e.g., RECORD,X or RECORD B,X.
All uninitialized values are cleared.

DATA STATEMENT
a)

Normal Form data name,
(optional)

data specification,
(required)

initialization specif.
(optional)

For example: F IELDl, D4, 1234
FIELD2,A4, 1 ABC4 1
b)

Operator Initialization - Specified by a P and causes
entry of data from keyboard before program execution,
e.g., RNDATE,A8,P.

Date Initialization - specified by a D and causes
entry of the Monitor date •

A data statement with an
initialization specification. !f no value is
specified the field is
cleared.

2-11

Dev

PROCEDURE SECTION
28.

QUESTION:

IN
OUT
UPDATE

What is the compiler statement that separates
the data and procedure sections?
***

ANSWER:

29.

QUESTION:

The PROC statement separates the data and
procedure sections.

What is the difference between a procedural
statement and a data statement?

Mass storage device to be used for input.
Mass storage device to be used for output.
Mass storage device to be used for random
access.
Input from terminal keyboard.
Output to terminal printer or display.
Line printer.
Card Reader.
Paper tape reader.
Paper tape punch •
Input from a file created on the system
device with the editor.

KBD

TTY

T
L

LPT
CDR
RDR
PTP
SYS

***

ANSWER:

Abbreviation Meaning

c
R

Procedural statements are executable.
For example:
INIT

INIT(l, KBD)
wi 11 initialize the terminal keyboard and any references to channel
l will be references to the terminal keyboard.

In a computer program, procedural statements are executed sequentially, the sequential execution of instructions can be changed by a
branching instruction.

Only mass storage devices (disk or DECtape) need be INITed. It is
optional for al I other devices. If not specified, the following
channel number assignments are assumed:

The first procedural statement discussed is the file-initialization
statement. The general form is:
INIT

(channel,

dev,

data file name,

logical unit)

5=PTR
b=LPT
7=KBD

The INIT statement is used to associate a channel number with a
device and to initialize that device. Channel is a number from
l to 15 which is to be linked to a logical or physical device. This
number is then used in other statements, such as XMIT, to refer to the
same device.

8=TTY
30.

Dev is the name of the COS 300 device to be associated with the
channel number. These names can be abbreviated, since only the
first character is checked. The fol lowing I ist contains the valid
dev names:

QUESTION:

Write a statement to initialize the terminal
display and assign it to channel 8.
***

ANSWER:

2-12

INIT(8, TTY).

However, COS 300 has a !ready assigned the terminal display to
channel 8. This statement is redundant. Only mass storage devices
need by INITed.

31.

QUESTION:

initialize a second DECtape data file
called MASTER which will be referred to
as channel 3 and be used for output.

initialize a card file containing transactions which will be referred to as channel
5 and be used to update the input MASTER
file.

Write a statement to initialize the line printer
and assign it to channel 1 •

***
ANSWER:

***

INIT(l, LPT) or INIT(l, L).
Both statements are identical in DIBO L.

ANSWER:

Only mass storage devices specify the data file name, which is required, and a logical unit number, which is optional. The data file
name is an alpha constant or a variable which is physically written
on this file. It can be up to six characters; anything in excess is
ignored. Any valid COS character can be used to make up the
name. If a variable is used with the P option, a file name can be
specified at run time.

INIT(2, INPUT, 'MASTER')
I is sufficient in place of INPUT. Also
the following message would occur at
run time:
MOUNT MASTER #01 FOR INPUT:
at which time the operator would respond
with the logical unit where the file could
be found.

Unit is an optional decimal expression used with I, 0 and U device
codes to specify the logical unit where the data file is stored or to
be stored. If the logical unit is not specified, a MOUNT message
wi 11 occur at run time.

INIT(3,0UT, 'MASTER')
0 is sufficient in place of OUT. A
message would appear at run time:
MOUNT MASTER #01 FOR OUTPUT:

Logical units are specified in SYSGEN and divide the available mass
storage into 15 possible areas for data files. These areas can be
different sizes (in multiples of 8000 characters) and more than one
area can be assigned to one physical device.

to which the operator would respond as in
(a)•

c)
32.

QUESTION:

Write the statements necessary to
a)

initialize a DECtape data file called
MASTER which wi 11 be referred to as
channel 2 and be used as input.

2-13

+NfT(5,COR)
INIT(5,CDR, 1 TRANS 1 ) would be incorrect
since the card reader is not a mass storage
device and cannot have a file name
associated with it.

33.

QUESTION:

How would you write a statement to initialize a
file on logical unit 12 called MASTER which
will be accessed directly and which will be
referred to as channel 13?

ANSWER:

The statement TAPEID,A6,P will allow the
operator to enter a six-character file name
whenever the program is run.

***

ANSWER:

XMIT

INIT(l 3, UPDATE, 1MASTER 1 I 12)
To read or write a record, the transmit data statement is used. Its
general form is:

34.

QUESTION:

Which of the following INIT statements are
invalid and why?
a)
b)
c)
d)
e)
f)
g)
h)
i)

j)
k)
I)

XMIT

INIT(l, INPUT I 1 FILEA 1 ,4)
INIT(3, IYBDGH KL, I LABEL')
INIT(2,X, I LABEL')
INIT(5, KBD)
INIT(5, IN 1 MAST')
INIT(8)
INIT{l 3, KEYBOARD)
INIT(7, TTY)
!NIT(15,UPDATE, 1 .$ 11 # 1 )
1(12,K)
IN IT (1 I I, I $TEM pI I 8)
INIT(5,0, TAPEID,3)

35.

QUESTION:

c)
e)
f)
h)
i)

record,
(required)

end of file label)
(only for input file)

Examples of the transmit-data statement are below:
a)
b)

X is an illegal dev.
A comma is missing between IN and MAST.
The -dev spec Hi cation i-s missing.
Missing right parenthesis.
IN IT cannot be abbreviated.

XMIT(l ,OUTBUF)
XMIT(2, INBUF,EOF)

Assuming channel l has been previously IN ITialized for output, statement a wou Id transfer the contents of RECORD
OUTBUF to channel l •

Assuming that channel 2 has been previously INITialized for
input, statement b would transfer data into RECORD INBUF
from channel 2.

36.

QUESTION:

***

ANSWER:

(channel,
(required)

What is accomplished by the following DIBOL

program?
START
RECORD INBUF
INA,Al 0
INB,A6
INC,A6
RECORD
DATE,A8, P

Statement I in the preceding question is val id
since a variable may be used as a data file
name. How can the data file name be varied
during each run without changing the program?
***

2-14

PROC
INIT(2, IN,11NFILE 1 , 14)
BEGIN,XMIT(2, INBUF I EOF)
GO TO BEGIN
EOF I FINI (2)
STOP
END

FINI

37.

QUESTION:

***
ANSWER:

The FINI is a close file statement and must
refer to a previously INITialized file. For
output files, an end-of-file mark is written
onto the file and the file is rewound.

QUESTION:

What is accomplished by statements 1 through
4 in the following exampie'?

***
ANSWER:

What is the function of the Fi NI statement?

When the program is run, the terminal will
output ENTER DATE and wait for the operator
to input an eight-character date (note the P
opti~n on data-item DATE). Channel 2 will be
initialized and all records will be read from
channel 2 into the area assigned to RECORD
INBUF; after all records are read, the program
wi 11 transfer to end-of-file routine (EOF) in
which channel 2 is rewound, and then the
program will stop. The END statement and
STOP statement are optional.

38.

START
RECORD ABC
A,AlO
NUMS,Dl5
BUF ,Al 00
PROC
A=

2
3
4

NOTE

'
,NUMS=

I BUF (56, 70)=
,ABC=

If the BEGIN statement were BEGIN,XMIT(2, INBUF) an error
message is output when an end-of-file occurs.
ANSWER:
It is also possible to XMIT partial records. In the previous example
assume that the first 10 characters from each input record would be
written onto the tine printer. The statement wou~d k>ok like:
XMIT ( 6, INBUF (l, 12))
and would be added after the BEG IN statement. The character
count of a record is contained in its first two characters. To output
a partial record of 10 characters, the program must specify the first
12 characters. This character count is generated automatically by
the COMPiler and does not interfere with the first field in a record.

Statement 1 sets the ten character field A to
spaces.
Statement 2 sets the 15 character field NUMS
to zeroes.
Statement 3 sets the characters 56 thiOugh 70
of field BUF to spaces.
Statement 4 sets the record ABC to spaces.

An attractive feature of the DIBO L language is the obi Iity to
reference characters within a field. The notation BUF (56, 70)
allows the programmer to reference characters within a data element

2-15

without assigning a specific data name. The general format to
accomplish this is:

This will accomplish the same as NUM(5)= which is in the previous
example.
NOTE

Data name (starting character position, ending character position)

39.

QUESTION:

An entire array cannot be referenced, only a single element within
an array. However, it is possible to reference an entire array by
redefining the array, using RECORD,X (overlay). For example:

What would be accomplished by statements 1
and 2 in the following example?

1
2

RECORD

START
RECORD B
NUMS, 10D2
Bl ,5A6
PROC
I NUMS (5)=
,Bl (4)=

NUMS,5D2
RECORD,X
NUMSl ,DlO
PROC
51 I NUMSl=
This will set the entire array of NUMS to zero.

***
ANSWER:

Statement 1 zeroes the fifth element of the
array NUMS.
Statement 2 sets the fourth element in the array
Bl to spaces.

!n summary the CI ear Data Statements have the foi lowing formats:
Destination field= e.g., A=
Destination field (subscript) = e.g., A(4)=
or
A(B)=
or
A (51 , 71)=

This notation is called subscripting. It allows the programmer to
reference a specific data element of an array. This form of subscripting must be a positive non-zero number, data name, or
expression. The data name option is cal led variable s-ubscripting.
For example:

ALPHA=ALPHA
Another type of data manipulation is the move-alphanumericvariable statement. It takes the general form:

START
RECORD

alpha field = alpha field
(destination)
(source)

NUMS, 10D2
A, Dl
PROC
A=5
NUM(A)=

Th is allows one alpha field to be moved to another alpha field. If
the source is shorter than the destination, the result is left-justified
with the right-most characters undisturbed. If the source is longer

2-16

than the destination, the result is left-justified and the right-most
characters are not moved to the destination fie id.

40.

QUESTION:

In review, the general format of move alpha to alpha data element
is:
Alpha field= alpha field
(destination)
(source)

What is the value of A in the following example,
after the move has been executed?

DECIMAL=DECIMAL or EXPRESSION
Statement

START
RECORD
A,A5, 1 ABCDE 1
B,A3, 1 FGH 1
PROC
A=B

decimal field= arithmetic expression
(desf.:ination)
(source)

***
ANSWER:

41.

QUESTION:

Variable A now has the value FGH DE. The
source is shorter than the destination field.
The right-most characters are undisturbed.

What is the value of NAME in the fol lowing
example?

Another form of data manipulation is moving a decimai expression to
a decimal field. The general format for this expression is:

The arithmetic expression may be any expression with decimal elements, subscripted data elements, constants, and the operators pius
(+), minus (-), multiply (*)and divide (/). The contents of parentheses are performed first, division and multiplication next, fol iowed
by addition and subtraction. The destination field would be rightjustified after the move. Below is an exampie:
START
RECORD

START
RECORD A
NAME,A4, 1 FRED 1
NAMEl ,A7 TI JOH NSON 1
PROC
NAME=NAMEl

QORDER, D4,0002
UCO ST T D4, 0200
ECO ST T Dl 0
X, D2,04
Y,5D3,000,007,100,025,023

***
ANSWER:

PROC

NAME now has the value of JOHN.

NOTE

3
4

While the receiving field is changed (destination), the sending
(source) field remains unchanged, so NAMEl still has the value
JOHNSON.

2-17

ECO ST=UCOST*QORDER
X=X+l
Y(l )=Y(X)+(25*Y(2)+Y(3))/Y(4)
X=Y(3)+Y(4)

Statement l)

ANSWER:

ECOST is calculated by multiplying UCOST and
QORDER. In the above example, the answer would
be: ECOST=0000000400. The result is rightjustified in ECOST with the leading two characters
set to zero.

Statement 2)

The new value of X shal I be X+l (answer, X=05).

Statement 3)

The first element in array Y will be equal to the
fifth element in array Y(X=5), plus the fol lowing
quantity: 25 multiplied by the second element in
array Y plus third element in array Y, the resu It
of this multiplication and addition is divided by
fourth element in array Y. The answer would be:

Subscripted variables are Y(3), Y (2); decimal
variable is Z; constants are 66, 13, 2; the
arithmetic operators used are +, *, - , /.
NOTE

The words variable and field can be used interchangeably.

43.

QUESTION:

Is the expression X=Y(2) equal to X=Y*2?
***

ANSWER:

No. Y(2) is a subscripted data element denoting the second element of an array with the
name Y. The expression X=Y*2 is the equivalent of multiplying Y times 2 and storing it
in X.

QUESTION:

What is the expression which would accomplish
the fol lowing?

Y (1) = Y (05) + (25 * Y(2) + Y(3))/Y(4)

y (1) = 023 + (25 * 007 + l 00)/025
y (1) = 023 + (275)/25

44.

y (1) = 023 + 011
a)

Take a number X and add it to the second
element in an array named K.

Take the result of that operation and
divide it by 145 and store it in M.

Y (1) = 034
Statement 4)

X is set equal to 25. If the destination field is too
small to contain the source field or source expression,
the high order digits are lost.

***
ANSWER:

42.

QUEST ION:

In the fol lowing expression, explain the items,
i.e., decimal field, subscripted field, constants, and the operators, plus, minus,
multiply, and divide.

M=(X + K (2))/145
If X + K (2) were not in parentheses, K (2)
would be divided by 145 before adding X.

In summary, the decimal to decimal move has the general format of:

X=Y (3)+Y (2)+66* (13-Z)/2

decimal field= arithmetic expression

***

A= A+ B/C
A=B

2-18

Decimal to Alpha
Alpha to Decimal

with leading zeroes, if needed. If the destination field is too
smal i, high order characters are lost.

The two forms of converting from one data type to another are:
46.

45.

Decimal field = alpha field

Alpha field= decimal field or decimal expression and an
optiona I format.

QUESTION:

What would be the contents of Bl and Al
after the following conversions?
START
RECORD A
COST, D4, 9999
Al I D5
RECORD B
NUM,A6, 1678912 1
Bl ,A6
PROC
Bl=COST
Al=NUM

In the following example, data fields are
described in both aiphanumeric and declmai
formats. Convert TOT from decimal to an
alpha format of corresponding length and store
in Al; and convert NUM to its decimal format
of corresponding length and store in Bl •

***

START
RECORD A
NUM,A6
A1,A6
RECORD B
TOT ,D6
Bl, D6
PROC

ANSWER:

Bl =COST (converts decimal to alpha). Bl
would contain 9999 right-justified with two
ieading blanks. Al=NUM (converts an alphanumeric number to decimal). Al would contain
78912; the high order character is lost.

Decimal to Alpha with Format

***
ANSWER:

QUESTION:

Al=TOT (converts decimal to alpha)

In business data processing, it is frequently desirable to output
decimal information with imbedded commas, o dedmol point-and
(if needed) a minus sign. For example, -34, 259 .00 is easier to read
than -3425900. DIBOL makes it possible to accomplish the formatting of decimal information during the conversion from decimal-to
alpha format. The general form of conversion is:

Bl =NUN\ (converts alpha to decimal)

The result of the conversion is always stored in the destination field
(the expression located to the left of the equal sign). The decimalto-alpha conversion is always right-justified with leading spaces, if
needed. If the destination field is too smal I, high order characters
are lost. The alpha-to-decimal conversion is also right-justified

alpha field=decimal field or decimal expression, format

2-19

For example, if B=l 256mOO (decimally formatted), the expression,
A=B, 1 -X,XXX,XXX.XX 1 will move B to A and cause A to look like
this:

49.

QUESTION:

START
RECORD A
Al ,A7
A2,A8
A3,All
RECORD
NUM,D6, 100000
Bl ,A7, 'CREDIT ....... I
B2,All,'TO DIGITAL'
PROC
Al=Bl
A3=B2
A2=NUM,
.XX'
XMIT (8,A)

l , 256, 777 .00 with no minus sign, since the number is greater than
zero. A must be defined as an Al 3 to hold a ful I nine-digit negative
number.

47.

QUESTION:

For B=4432567 - (assume two decimal places);
what would the conversion instruction look
like?

***
ANSWER:

A=B'-XX,XXX .XX' or 'XX,XXX .XX- 1
(-44,325.67)
(44,325.67-)

•x,xxx

***

The minus sign in the edit format can be either on the left or on the
right. If the decimal value is positive, the sign will appear as a
blank.

48.

QUESTION:

ANSWER:

·-x,xxx,xxx .xx·

Each X represents a digit and leading zeroes are automa ti cal I y. suppressed.
If a minus sign is the first or last character in a format
statement, a minus sign is inserted when a number is
negative.

***
ANSWER:

CREDIT l ,000.00 TO DIGITAL

Most printing characters on the line printer or terminal can be used
in a format string; but the fol lowing characters have a special
meaning:

Since commas are inserted only if the corresponding comma has a significant digit to the
left, if B=31 l, what would be the value of A
after the following?
A=B,

What is output to the terminal by the fol lowing
program?

Where b signifies a space, A would be equal to
bbbbbbbbb3. l l. When a decimal field is
converted, it is right-justified.

Inserts a period and zeroes are no longer suppressed.
Inserts a comma if there are significant digits to the left.

2-20

Suppresses a digit position and right-justifies it.

If an asterisk is the first character of a format, it replaces
all leading zeroes.

50.

QUESTION:

In the following example, what is the result
of each statement in the PROC division?
START
RECORD A
Al ,A8
A2,A4
A3,A4
A4,Al l
FMT rA4, 'X .XX 1
RECORD B
DATE, 06, 103070

Examples:
NUM, 03, 987
Al ,A3
Al=NUM,

·xxz·

result is:

Al =b98

(where b signifies a blank)

NUM; D3; 123
NUM, 05, 12345
PAY,A9
PAY=NUM, 1 *X,XXX
result is:

COST, 03, 999
TOT I Dl 2, 000007894211

.xx·

PROC
a)
b)
c)
d)
e)
f)

PAY=***l 23 .45

The remaining characters are treated as insertion characters e For
example:
OATE=l 02370
Al=OATE, 1 XX/XX/XX 1
Al=l0/23/70
or
NUM=987
Al=NUM,

·xxxo·

result is:

Al=9870

·-xxx,xxx .xx·

***
ANSWER:

result is:

·xx/xx/xx·
·xxz·
·xxxo·

Al=OATE,
A2=NUM,
A3=COST,
A4=TOT, 1 -XXX,XXX .XX*'
A4=TOT,
A2=NUM,FMT

Statement a)
Statement b)
Statement c)
Statement d)

Statement e)
Statement f)

When using a comma, period, slash, minus sign, or any other
notation, it must be counted as a character position. In the above
example using slash, Al must be defined as an eight-character
alphanumeric field.

A 1=1 0/30/70
A2=bbl2
A3=9990
A4=*78, 942 .11 * (an asterisk
which is not the first character
in a format wi 11 act as an in. serlion character and afso
replace leading zeroes.)
A4=bb78, 942. 11
A2=l .23

In summary, the data manipulation statements have the fol lowing
formats:

2-21

Format

NOTE

Example

CI ear Field=
Alpha Field=Alpha Field
Decimal Field=Arithmetic Expression
Decimal=Alpha
Alpha= Dec ima I
Alpha=Decimal, format

A powerful feature for the data manipulation statements is that
record names can be used. For example:

A=
A=B
A=B*C/D
Al=NUM
Bl=TOT
A=B, ·-xx,xxx.xx·

START
RECORD AAA
Al ,A80
RECORD BBB
Bl ,A80
PROC
AAA= BBB
STOP
END

Note that subscripting can be used in any data manipulation statement.
In most of the examples in which subscripting was used, it was done
by referencing specific elements of an array, i.e., NUM {2)=. It
is often desirable to change the value of the subscript. This is
done by using a data name for the subscript. For example:

Statement AAA=BBB is valid. A record name can be moved to
another record name. Record subscripting is also legal. For example:

START
RECORD C
Cl I l OA5
RECORD
A,D2
B,A5, 1 DIBO L1
PROC
A=l
Cl (A)=B

START
RECORD AAA
Al ,A80
RECORD BBB
Bl ,A80
PROC
AAA(l )=AAA(2)
STOP
END

This plac~s the yqlve of _DIBQJ in the firs_t element of the array Cl •
If al I elements of the array were to be set to the value DIBO L, the
procedure section wou Id look Iike:

GO TO

PROC

The next type of statement is the GO TO statement.

A=l
Cl (A)=B
A=A+l
IF (A.LT.11) GO TO BEGIN
STOP

BEGIN,

51.

QUESTION:

From the previous section (and using Foldout #3),
what is the purpose of the basic GO TO statement?
***

END

2-22

ANSWER:

This statement causes the program controi to
branch to the executabie statement in the
procedure section with the specified lobe!, and
has the form:

53.

QUESiiON:

is the fol lowing use of GO TO correct?
START
RECORD B
Bl ,A50

GO TO label

PROC
INIT (2, I, 1HOHUM 1 , 6)

The label must be a statement label assigned to the statement in the
PROCedure section where control is to be transferred. It cannot be
a data name. A data name refers to an element which has been
defined in the data section.

LOOP I

XMIT (2, B, EOF)
XMIT (8, B)
GO TO LOOP

EOF,

FINI (2)

END
52.

QUESTION:

Is the following use of GO TO correct?

***
ANSWER:

START
RECORD A

Al ,A90

Yes, LOOP is a label associated with a statement in the procedure section. LOOP is not a
data name.

PROC
INIT (2, I, 1FILEXX 1 )
XMIT (2,A)
GO TO START
FINI (2)
STOP

Another type of GO TO statement is the computed GO TO. It has
the form:
GO TO (label 1, label 2,
expression

...... , label n), decimal

END
For example:

***
ANSWER~

GO TO (LOOP I RUN I STOPS) I KEY

No• START is not on executobie statement.
Executable statements are found only in the
procedure section of the program.

This statement reads 11 lf decimal variable named KEY is equal to 1,
then go to LOOP; if it is equal to 2, then go to RUN; and if it is
equai to 3, go to STOPS. if the variable KEY is not equal to l, 2
or 3, control passes to the next statement in sequence. There can be
any number of labels in a computed GO TO statement.

2-23

54.

QUESTION:

NOTE

If NUM is equal to 2, what does the following
accomplish?

The format requires a period immediately before and after the two
character relation codes. If an expression is an alphanumeric
constant, it must be enclosed in apostrophes.

GO TO (Xl I X2, X3), NUM

***
ANSWER:

The statement is executed if the relation is true. Statement is one
of the following:

The program branches to the statement labeled

X2.

55.

QUESTION:

GO TO LABEL
CALL LABEL
RETURN
ON ERROR
STOP
TRACE
NO TRACE

In the above example, if NUM is equal to 6,
what happens?

***
ANSWER:

Control passes to the next statement in
sequence.

(Options which are unfamiliar wil I be explained later in this section.)

56.

QUESTION:

An IF statement transfers control on the basis of the results of an
expression. The form of the statement is:

***
ANSWER:

IF (expression l .rel. expression 2) statement

IF (NUMB .LE. 46) GO TO LOOP

In a decimal comparison, the shorter of two fields is left zero filled
before the comparison.

The data items for comparison may be constants, variables, or
arithmetic _expressions_. They_must_be both alphanumeric or both
decimal. The relations are:
• EQ.
.NE.
.LT.
• LE.
• GT.
• GE •

Write an equivalent DIBOL statement for the
fol lowing. If NUMB is less than or equal to
46, then go to the statement labelled LOOP.

57.

equal
not equal
less than
less than or equal
greater than
greater than or equa I

QUESTION:

ANSWER:

Write a DIBOL statement to do the following:
If DESC is equal to the alpha constant HAPPY,
terminate program execution •

***
IF (DESC .EQ. 1 HAPPY 1 ) STOP
NOTE

Two fields to be compared may be of unequal length. The longer of
two Alpha fields is shortened on the right to the same length as the
shorter field.

2-24

58.

QUESTION:

Is the following use of the IF statement correct?

PROC
CALL LIST
;control returns here

START
RECORD
NUMB, D3, 223
ALPH, A3, 1 ZAP 1
TOTL, D3, 999
PROC
BEGN,

LIST I B=B+l
RETURN

NUMB= NUMB+l
IF (NUMB .EQ. ALPH) TRACE

NOTE

STOP

Control can oass directly to a subroutine. However, its RETURN
statement, ~hen execut~d, wi 11 cause a Run-Time error.

END
***
ANSWER:

Use of the IF statement is incorrect. NUMB
(which is a decimal item) cannot be compared
with ALPH (which is an alpha item). A compiler error will result.

59.

QUESTION:

Is the fol lowing correct use of the subroutine?
START
PROC

CALL
RETURN

CALL SUBl
SUBl I

When the same coding is used several times in a program, it may be
written once as a subroutine. To use the subroutine write:

x= x+ l
IF (X .NE. 3) GO TO EXIT
CALL SUB2

CALL label

EXIT I
SUB2,

The CALL statement does two things. It saves the address of the
statement following the CALL in the RETURN statement of the subroutine and then performs an unconditional branch to a subroutine.
The return from a subroutine is to the next statement after the CALL
statement. This is accomplished by the RETURN statement. For
example:

ANSWER:

2-25

RETURN
X=X*2
RETURN

***
The example is correct. SUB2 is an example of
a nested subroutine, called by SUBl. SUBl
cal Is SUB2, which ~ultiplies .the variable X by
2 and returns to SUBl, which returns to the instruction fol lowing the original CALL statement.
If a subroutine is entered other than by a CALL
it is treated in sequential coding, not as a
subroutine.

STOP

61 •

QUESTION:

STOP causes the program to terminate its execution and to return
control to the DIBO L Monitor. For example:

***
ANSWER:

It is the output record from which al I records
are written by channel 2.

QUESTION:

What is the purpose of the X in describing
OUTBUF?

START
BLOCK A
Al I Al 0
A2, A2

62.

RECORD B, X
Bl I Al2
PROC
INIT (2, IN, 1 AFILE 1 I 3)
LOOP I

EOF I

***

XMIT (2, A, EOF)
XMIT (8, B)
GO TO LOOP
FINI (2)
STOP

63.

ANSWER:

The five fields of OUTBUF occupy the same
area of computer memory as the five fields of
INBUF (the fifth field of INBUF is not
label led.

QUESTION:

Which statement separates the data section
from the procedure section?

END

***

This example would print each record from logical unit 3 onto the
terminal until end-of-file was reached. At that time, control would
transfer to EOF where logical unit 3 would be closed. The program
would then terminate by transferring control to the DIBOL Monitor.
In this example STOP is optional since it is physically the last
statemenHn--the program •

64.

QUESTION:

ANSWER:

The PROC statement.

QUESTION:

Why should the input record occupy the same
area of computer memory as the output record?

***

On Foldout #3 is a Iisting of a complete DIBO L-coded program.
Examine it, and answer the fol lowing questions.

60.

From statements 16 and 20, what is the function
of the block named OUTBUF?

ANSWER:

From statements 15 and 17, what is the function
of INBUF?

***
INBUF is the input record into which al I data
from channel 1 is stored.

2-26

With the exception of the field named ECO ST,
the output records contain the same information
as the input record. Thus, not only is computer
memory saved, but many more instructions
needed to move fields from one buffer to
another are eliminated.

65.

QUESTiON:

ECOST is defined as decimal and the field
it overlays is alphanumeric. Is this valid?

•

69.

QUESTiON:

***
ANSWER:

Yes. A decimal field may be defined as alphanumeric (and vice versa).

QUESTION:

Put statement number 18 into your own words.

***
A..._ 1..-\AJrn

1-\l~.:>VV Cl\:

QUESTION:

70.

QUESTION:

Statement 17 carries the solution. It says
11
Read a record from channel l and store the
information in the record labelled INBUF.
If theie aie no moie iecoids, go to the in~
struction label led EOF. 11

START
RECORD

How do we know statement 17 is a read
statement? (two reasons)

RECORD

***

In the example program, STOCKN refers to a

ANSWER:

stock number, DESC refers to an item description, UCOST refers to unit cost of the item,
QORDER is the quantity ordered, and ECOST

First, statement 15 INITializes channel 1 which
contains a file called 1 ITEM 1 as an input device; second, only read uses of the XMIT

denotes the extended cost. Describe in your

statement have three parameters (channel,

words the operation of this program (the logic).

record, and end-of-file routine name); write
statements have only two parameters (channel
and record).

***
ANSWER:

SAMPLE PROGRAM #2

"If data name STOCK~-J is less them 1OOQ.. then
go to the instruction labeled LOOP. Otherwise, execute the next sequential instruction • 11

67.

FOLDOUT #3

***
ANSWER:

66.

There doesn't seem to be any way for the program to execute statements beyond statement
21 (an unconditional branch). How is the
statement labelled EOF executed?

The program reads records containing a stock
number, item description, unit cost, and
quantity ordered. It skips records which have
a stock number less than l 000. Output records
are generated with the same information as the
input with an additional item -- an extended
cost which is the product of the unit cost and
the quantity ordered.

PROC

LOOP,

EOF,

;1
INBUF
STOCKN,
DESC,
UCOST,
QORDER:

;2
D4
A25
D5
D4
A9

OUTBUF,X
Al I
04
A2,
A25
A3,
05
A4,
04
ECOST,
09

2
IN IT (l , IN I I IT EM I I 4)
INIT (2, OUT I I ITEM' I 12)
XMIT (l ,INBUF,EOF)
IF (STOCKN .LT .1000) GO TO LOOP
ECOST=UCOST*QORDER
XMIT (2,0UTBUF)
GO TO LOOP
FINl(2)
FINl(l)

ST01>

;4
;5
;6

;7
;8
;9
; 10

;11
; 12
; 13
;14
; 15
; 16
; 17
; 18
; 19
;20
;21

;22
;23
~2:4

END

The program reads records containing a stock number / item descrip68.

QUESTION:

Put statement 16 into your own words.

ANSWER:

INITialize channel 2 as an output device which
wil I write a file called ITEM on logical unit 12.

tion, unit cost and quantity ordered. It skips records which have a
stock number less than 1000. Output records are generated with the
same information as the input with an additional item -- an extended
cost which is the product of the unit cost and the quantity ordered.

***

2-27

EXPLANATION OF FOLDOUT #3
INVENTORY PROBLEM
START
RECORD

PROC

INBUF
STOCKN,D4
DESC,A25
UCOST, D5
QORDER,D4
,A9
OUTBUF,X
Al ,D4
A2,A25
A3,D5
A4,D4
ECOST, D9
2

LOOP,

INIT(l, IN, 1 ITEM 1 ,4)
IN IT (2, OUT I 1 ITEM 1 I 12)
XMIT(l, INBUF, EOF)

RECORD

IF(STOCKN .LT .1000)
GO TO LOOP
ECOST=UCOST*QORDER
XMIT(2,0UTBUF)
GO TO LOOP
EOF,

FINl(2)
FINl(l)
STOP

END

;input record
;Stock number, 4 digits
;Description, 25 characters
;Unit cost, 5 digits
;Quantity ordered, 4 digits
;Unused field
;A redefinition of the input record

;Extended Cost, 9 digits
;Begin Procedure Section, 2 mass storage
;files will be open at one time
;Initialize file 1 as an Input device
;Initialize file 2, as an Output device
;Read a record from channe I 1, and
;store it in record INBUF
;If stock number is less than l 000,
;read another record
;Extended cost would be calculated
;for STOCKN l 000 or over
;Write__ the_r:ecord OUTBUF onto _
;channel 2
;Go to statement LOOP to read
;another record
;OUTBUF file is closed and EOF mark
;is put at end of file
;INBUF file is closed
;OUTBUF file wil I contain all stock
;items with a stock number of l 000
;or over, with DESC, UCOST,
;QORDER, and ECO ST for each item.

2-28

!NCR
The INCR (increment) statement adds ones to a specified field and has
the form

I_oo.k a t..Fo Idou.t #4 an d "t
t"
1 s exp Iana.1on..

Th"
•
. 1s program con t ams
samples of the remaining statements to be explained in this section~

FORMS
INCR decimal field
The FORMS statement is used to format line printer output. It may
not be used with any other output device. It has the form:

The next two statements are identical

FORMS (channe I, skip-code)

DECFLD=DECFLD+l
INCR DECFLD

Channel is the channel number associated with the line printer. The
skip-code specifies the action to be taken:

Refer to statement 25 of Foldout #4 for another example.

0
71 •

QUESTION:

Given the fol lowing program which statements
are invalid?

l - 4095
-1

START
RECORD
A,D4

-2

B,A5

b)
c)
d)

C,D3
PROC
INCR B
INCR A
INCR A+c
C=INCR A

For example:
FORMS(6,3)
means skip three lines on the line printer;

***
ANSWER:

go to top of next page (skip to channel 1
of the vertical forms control tape).
skip this number of lines.
(LS8-E only) skip to channel 2 of the
vertical forms control tape.
(LS8-E only) print enlarged characters for
the next XMIT statement. Since characters are twice their normal width only 66
characters can be printed.

FORMS(6,0)

Statement a is invalid since variobfe B is
defined as alphanumeric.
Statement b is correct.
Statement c is invalid since expressions are
not al lowed in an INCR statement.
Statement d is invalid since INCR cannot be
part of a data manipulation statement.

means skip to the top of the next page;
FORMS(6, N)
means perform the function specified by the value of N.

2-29

72.

QUESTION:

In the following program, what is the result
of each FORMS statement?

b)
c)
d)
e)

TRACE
NO TRACE

START
RECORD
l,D2,20
J, D2, 03
PROC
INIT(3, LPT)
FORMS(3,0)
FORMS(6,0)
FORMS(J,3)
FORMS(J, -3)
FORMS(J*2, l+J-13)

These statements are used to debug a program. They can be inserted
anywhere in the PROCedure section. The form of the statement is:
TRACE
NO TRACE
When the TRAC::E statement is executed, program tracing is enabled
unti I the execution of a NO TRACE statement. When enabled each
DIBO L statement which is executed causes the fol lowing line to be
printed on the line printer:

***
ANSWER:

AT LINE n

Statement a will allow the line printer to skip
to a new page.
Statement b will also allow the line printer to
skip to a new page. The line printer may be
referred to as channel 3 since it was INITed
as channel 3 and as channel 6 since no other
device was INITed as channel 6.
Statement c will skip three lines on the line
printer. Variables or decimal expressions are
al lowed for the channel number of skip-code.
Stah~ment d is inval ic;I. The skip-code is
lncorrea~---

- -------- - -- -

where n is the source line number. If the statement is a data manipulation statement, the value stored in the destination field is also

printed:
AT LINE 200
0003
TRACing will not occur unless the program is RUN
with the /T option (refer to the System Reference
Manual for a more detailed explanation of this
op-Hon};;

-- -

Statement e will skip 10 lines on the line
printer.
The value of the first expression, J*2, is 6;
the value of the second expression, I+ J- 13
is l 0.

Indiscriminate placement of TRACE statements wil I
cause excessive output on the line printer. To use
a TRACE statement properly, the problem area in a
program should be determined and the TRACE/NO
TRACE statements used only in the problem area.

2-30

73.

QUESTION:

\A/hat output wi!! result from the TRACE
statement in the fo! !owing program?

QUESTION:

Vv'hich of the following are vaiid TRACE/NO
TRACE statements?

a)
b)
c)
d)

(Ii ne numbers)
START
0100
RECORD
0110
0120
ITEM,D5
HOURS,D2
0130
SALARY,D5
0140
WAGES, D7
0150
PROC
0160
HOURS=40
0170
SALARY=300
0180
TRACE
0190
WAGES=HOURS*SALARY
0200
IF~AGES·.EQ .1 OOOO)NO TRACE
0210
HOURS=lO
0220
IF(HOURS .EQ .1 O)GO TO NEXT
0230
NO TRACE
0240
0250
NEXT I WAGES=HOURS*SALARY
0260
NO TRACE
0270
HOURS=20
0280
WAG ES=HO URS*SALARY
0290
STOP

IF (A .GT .B) TRACE
CALL TRACE
NO TRACE
GO TO TRACE

***
ANSWER:

Statement a is valid.
Statement b wi!! CALL subroutine TRACE, not

enable TRACing.
Statement c is vc!id.

Statement d wi 11 GO TO a statement labelled
TRACE, not enable TRACing.

ON ERROR
The ON ERROR statement is often inserted in a source program prior
to a statement which, if in error when executed, would cause a
return to Monitor~ The form of this statement is:
ON ERROR label

***
ANSWER:

74.

where label is a statement in the PROCedure section where control
is to be transferred when an error is encountered. An example of
this statement is:

AT LINE 0200
0012000
AT LINE 0210
AT LINE 0220
lO
AT LINE 0230
AT LINE 0250

ON ERROR FIX
DECMAL~ALl'HA

FIX,

0003000

AT LINE 0260

Refer to statement 17 of Foldout #4 for another example. The ON
ERROR statement eliminates a return to Monitor for the fol lowing
conditions:

2-31

75.

division by zero;
in alpha to decimal conversion, a character other than
0 to 9, plus, minus or space;
more than 15 digits in a decimal field used in a calculation
(the field, of course, would have to be defined as Dl 6,
Dl 7, or larger);
an end of file label was not specified in an XMIT statement
and the end of the input file was reached;
input record was greater than its specified size;
no file was specified in a RUN command to satisfy an
INIT(SYS) statement
direct access of a record beyond the end of a file.

QUESTION:

Which of the following statements need an
ON ERROR statement to precede them to
prevent program termination?

76.

ANSWER:

Statement a needs ON ERROR because of
division by zero.
Statement b does not need ON ERROR.
Statement c does not need ON ERROR because
DECMAL does not contain a value exceeding
15digits.
Statement d does not need an ON ERROR
since a plus sign is a val id character in alpha
to decimal conversion.
Statement e needs an ON ERROR statement
since none of its characters are val id in alpha
to decimal conversion.
Statement f does not need an ON ERROR
statement.

QUESTION:

What happens in Sample Problem #2 if statement 17 is:

Assume the fol lowing data section
LOOP ,XMIT (1, INBUF)

START

***

RECORD
DECMAL,020,00000000000000050000

ANSWER:

1,05
ALPHA,A5, 1 ABCDE 1
BETA,A5, 1 12345 1
PH I ,A3, 1 +25 1
WORK,D8
j,t>!>, 15-0
a)
b)
c)
d)
e)
f)

WORK=J/I
WORK=l/J
WORK=DECMAL *2
l=PH I
l=ALPHA
l=BETA

The program will run properly until the end of
file is reached. At that time, the program
will return to Monitor because there is no end
of file label in the XMIT instruction. This
problem can be avoided by leaving statement
17 in its original form or by preceding state-nienf 17 with an ON ERROR statement~
ACCEPT

The ACCEPT statement stores input from the keyboard in a specified
alpha field or record as well as the decimal equivalent of the
terminating character. It is used mainly with the DISPLAY statement.
It has the form:

***

ACCEPT{terminating character,alpha field)

2-32

where the terminating field is usually defined as a two digit field
and the alpha field contains the keyboard input. ACCEPT is often
used when certain action is to be taken depending upon the value of
the terminating character. The values for the terminating characters
can be found in Table 1-1 of the System Reference Manual. An
example of this statement is:

78.

QUESTION:

How can the ACCEPT statement in the preceding
problem be modified to ACCEPT only l 0 characters? (Show two ways.)

***
ANSWER:

LOOP, ACCEPT(TCHAR, KBD(l, l 0))
or define KBD as an Al 0 field.

DISPLAY

DECMAL,D2
ALPHA,AlO

The DISPLAY statement is used primarily with the VT05 terminal to
dispiay a message at a specified iocatlon on the screen. Any of 20
rows or lines and 72 columns may be specified. The form of the
statement is:

ACCEPT (DEC MAL, ALPHA)

DISPLAY(row, column, field)

Another example of this statement is statement 29 of Foldout #4.

77.

QUESTION:

where row specifies the line and column specifies the column where
field is to be displayed. The field may be a decimal constant, an
alpha I iteral, an alpha variable or a decimal variable. The
foiiowing decimai constants or decimal variables perform a special
function:

How would you write a program which wili
ACCEPT 15 alphanumeric characters? If
CTRL/U, a terminating character with a
value of 21 is typed, restart ACCEPTance of
input. Use TCHAR as the terminating character and KBD to store keyboard input.

0 = position the cursor at the row and column specified;
l

***
ANSWER:

= clear the scope from the row and column specified to

the end of the screen and position the cursor at row
and column;
2 = clear the scope from the column specified to the end of
the I ine and position the cursor;
25 = sound the bel I or beep and position the cursor.

START
RECORD

TCHAR,02
KBD,A15
PROC
LOOP ,ACCEPT(TCHAR, KBD)
IF (TCHAR .EQ .21 )GO TO LOOP
STOP
END

Any other decimal codes are meaningless.

2-33

79.

QUESTION:

How would the DISPLAY statements be
written to do the following?
a)
b)
c)

d)
e)
f)
g)

Clear column 8 thru 72 of line 12 on the
screen.
Clear column 3 thru 72 of line 5 and clear
I in es 6 thru 20.
Display the error message 'NOT
NUMERIC' at the beginning of the lost
line.
Ring the terminal bel I.
Clear column 6 thru 8 of line 20.
Display the contents of the alpha field
XYZ at line l, column 1 •
Move the cursor to row I, column J.

***
ANSWER:
START
RECORD

***
ANSWER:

a)
b)
c)
d)

f)
g)

80.

QUESTION:

TCHAR,D2
CHAR,A5
TEMP,D5
ONE, Al

DISPLAY(12,8,2)
DISPLAY(5,3, 1)
DISPLA Y(20, 1, 'NOT NUMERIC')
DISPLAY(0,0,25) ;row and column could
be any value but a 0 value for row wil I
not reposition the cursor.
This cannot be done with a DISPLAY
command. The minimum that could be
cleared is column 6 thru 72 of line 20.
However, displaying spaces wi 11 work.
For example: DI-SP LAY (20, 6 1 'L..JL-H-l)
DI SP LAY(l, l , XYZ)
DISPLAY(!, J,0)

PROC
LOOP I DISPLAY(l, 1, 1)
DISPLAY(l, l, 'CLIENT NUMBER L..J I
ACCEPT (TCH AR, CH AR)
ON ERROR FIX
TEMP=CHAR
CHAR= TEMP
DISPLAY(l, 15,CHAR)
STOP
FIX,
DISPLAY(0,0,25)
DISPLAY(20, l, 'NOT NUMERIC')
ACCEPT(TCHAR, ONE)
GO TO LOOP

How would you write a program to do the
following:
a)
b)
c)

Verify that the digit is numeric when
storing it in a five-digit field cal led
TEMP. If incorrect, sound the beep,
DISPLAY the error message NOT
NUMERIC on the bottom line, wait for
the operator to strike any key which
indicates he understands the error and
reenter the information.
Since the number may be less than 5
digits, right justify the number entered
before DI SP LAYing it.

Clear the screen.
DISPLAY 'CLIENT NUMBERL..J'
ACCEPT a 5 digit client number.

2-34

FOLDOUT #4

READ
WRITE

81.

QUESTION:

The READ and WRITE statements allow direct access of a specified
record. This record may be input from (READ) or output to (WRITE)
a specified file. The statement has the form:

***

READ (channel,record,record number)
WRITE (channel, record, record number)

ANSWER:

where channei is a number from i to i 5, record is a iabei previousiy
specified in a RECORD statement, and record number is a constant,
variabie or arithmetic expression specifying the record number to be
read or written. For example:

SIZE,
LENGTH,

READ(5, REC RDA, 20)
WRITE(K, REC, J-4)
The first example wil I READ the 20th record from channel 5 into
record RECRDA. The second example will WRITE REC as the j-4th
record onto channel K. Refer to Foldout #4 for more examples.

EOF,

NOTE
For a file to be accessed directly, it must be defined as an UPDATE
file. For example:
INIT(l, UPDATE, 1 FILEA 1 ,3)

How would you write a program which prints
every 10th record on the line printer (assume
the records are ca Iled RECA, are 50 characters long, are in FILEX in channel 3,
logical unit 6, and that direct access will be
used.

RCAD(t RECRDA, 20)
I

2-35

START
RECORD RECA
A50
D5
PROC
INIT(3, U, 1 FILEX 1 ,6)
LOOP, INCR LENGTH
ON ERROR EOF
READ(3,RECA, LENGTH*lO)
XMIT(6, RECA)
GO TO LOOP
FINl(3)
STOP
END

SAMPLE PROGRAM #3
START
RECORD ITEM
STOCKN, D4
DESC,
A25
UCO ST I D5
QORDER, D4
ECOST, D9
RECORD
LINECT, D2,50
REC,
D5
TCHAR, D2
RECORD KBDIN
CHAR
A5
PROC 1
INIT(i, UPDATE,' ITEM' 12)
LOOP I CALL GETKBD
ON ERROR MESAGE
REC= CHAR
NO TRACE
IF(REC .EQ .l OO)TRACE
READ(l, ITEM,REC)
IF(LINECT .LT .50) GO TO PRINT
FORMS(6,0)
LINECT =
PRINT I INCR LINECT
XMIT(6, ITEM)
GO TO LOOP
MESAGE, DISPLAY(2, l, 'NOT NUMERIC)
ACCEPT(TCHAR, KBDIN)
GO TO LOOP
GETKBD, DISPLAY(l, l, l)
GETA,
KBDIN=
ACCEPT(TCHAR, KBDIN)
IF (TCHAR .NE .21 )RETURN ;21 = CTRL/U
DISP
DI SP LAY(l, 1, 2)
GO TO GETA
I

;2
;3

;4
;5
;6
;7
;8
;9
i 10

i 11
i 12
;13

;l 4

; 15
;l 6
i 17

; 18
i 19

;20
;21
;22
;23
;24
;25
;26
;2T
;28
;29
;30
;31
;32
;33
;34
;35

;36

EXPLANATION OF FOLDOUT #4
DUMP SPECIFIED INVENTORY RECORDS
START
RECORD ITEM
STOCKN, D4
DESC,
A25
UCOST, D5
QORDER, D4
ECOST, D9
RECORD
LINECT, D2, 50
REC,
D5
TCHAR, D2
RECORD KBDIN
CHAR,
A5
PROC 1

MESAGE, DISPLAY(2, 1, 1NOT NUMERIC') ;Display error message
;terminal
ACCEPT(TCHAR, KBDIN) ;Wait for operator response indicating
;he has acknowledged the error message
GO TO LOOP
;Get next record number
GETKBD, DISPLAY(l, 1, 1)
;Clear the screen
GETA,
KBDIN=
;CI ear record
ACCEPT(TCHAR, KBDIN) ;Accept up to 5 characters; accept is
;terminated when 5 characters are typed
;or when a terminating (non-printing)
;character is typed
IF (TCHAR .NE .21 )RETURN
;If terminating character is not CTRL/U,
;return to main program
DISPLAY(l, 1,2)
;If CTRL/U, clear row 1 and
GO TO GETA
;accept input again

; Input record
;Stock number
; Description
;Unit cost
;Quantity on order
; Extended cost
;Working storage
;Number of lines printed on current page
;Record number of record to be printed
;Terminating character in an ACCEPT
;command
;5-character record for reading record no.
;A maximum of 1 mass storage device wi 11
;be open at the same time

INIT(l,UPDATE, 1ITEM 1, 12)

The program accepts a record number from the keyboard.
If the
record number is not numeric an error message is displayed and the
program waits for the operator to depress a terminating key before
restarting. When the record number is numeric, that record is read
directly from a file cal led ITEM and then printed on the line printer.

;Initialize a file called ITEM found on
;logical unit 12 for direct access
LOOP,
CALL GETKBD
;Get the record number
ON ERROR MESAGE
;Go to MESAGE if the next statement is
;in error (such as CHAR containing non;numeric characters)
REC=CHAR
;Move CHAR to the numeric field REC
NO TRACE
;Disable TRACE mode (it is initially
;disabled)
IF (REC .EQ .1 OO)TRACE ;Enable TRACE if record number 100
READ(l, ITEM, REC)
;Read record REC from ITEM file
IF(LINECT .LT .50) GO TO PRINT ;Skip to new page every 50 lines
FORMS(6,0)
;Skip to new page
LINECT =
;Clear LINECT
PRINT ,INCR LINECT
;Add 1 to LINECT
XMIT(6, ITEM)
;Print specified ITEM record on line
;printer
;Get next record number
GO TO LOOP

2-36

SECTiON SUMMARY

Data Manipuiation statement.
General form:

You have completed an in-depth discussion of the DIBO L language.
If you do not understand DI BO L c Iearly, by a 11 means study the
section a second time.

destination field=source field or expression
a)
b)
c)

In summary, the procedure section has the fol lowing instructions:
l)

Initialize File Device statement (as input or output).

d)
e)
f)

Geneial foim:
IN IT (channel, dev, data-file-name, unit)
Example:

INIT(2, IN,FILEX' ,3)
INIT(4,KBD)
2)

Transmit statement (Read-from or write-into file).

CI ear data (destination field= )
Move alphanumeric data (alpha data=alpha data)
Compute decimal data (decimal data= decimal
expression)
Convert alpha to decimal (decimal data=alpha data)
Convert decimal to alpha (alpha data=decimal data)
Convert decimal to alpha, formatted (alpha data=
decimal data, format)

GO TO statement (program control transfers to statement
label).
General form:
GO TO statement lobe!

General form:

Example:

XM!T {channel; record, end-of-file !abe! for
input files)

GO TO LOOP

Example:

XMIT(2, INBUF, EOF) Read from
XMIT(l ,OUTBUF) Write into

Computed GO TO statement (program control branches to
label l if the decimal data element is l, etc.).
General form:

Close Fi le statement.

GO TO (labell, label2, ••• , labeln),decimal
doto element

General form:

Example:

FIN I{channel)

GO TO (TAX,COST,PRICE),A2

Example:
FIN I (2)

2-37

11) INCR statement (adds 1 to a specified field).

IF statement {if the relation between the expressions is
true, con tro I goes to statement) •

General form:
General form:

INCR decimal field

IF (expression l .rel .expression2) statement
Example:

Examples:

INCR DECFLD

IF(A.EQ .B) GO TO C
IF (A .NE .1) TRACE
IF(LINE .GT .50) CALL HEADNG
IF (I. LT. l) RETURN
8)

12) FORMS statement (formats line printer output)
General form:
FORMS(channel, skip-code)

Subroutine CALL statement (control goes to statement
label).

Examples:
General form:

FORMS(6,0)
FORMS(6, -2)
FORMS(I, l 0)

CALL statement label
Example:

13) TRACE statement (enables program tracing for debugging).

CALL COST
9)

General form:

RETURN statement (program control returns to the statement after the last CALL).

TRACE

General form:

14) NO TRACE statement (disables program tracing).

RETURN
General form!
l 0) STOP statement (causes program to terminate and transfers
control to the Monitor).

NO TRACE

General form:
STOP

2-38

1I ...,
~\
I

Ot'-~ ERROR statement (prevents return to Monitor for

certain run time error conditions).

18) READ statement (allows a specified record to be read
directly).
General form:

General form:
ON ERROR statement label

READ (channel, record, record number)

Example:

Examples:

ON ERROR EXIT
READ(l, RECNAM,28)
READ(4, REC NAM, REC)

16) ACCEPT statement (used to get input from the terminal
when retention of the last character typed is desired).

19) WRITE statement (allows a specified record to be written

directly).

General form:
ACCEPT(terminating field, alpha field)

General form:

Examples:

WRITE(chonnel, record, record number)

ACCEPT (TCHAR, ALPHA)
ACCEPT(TCHAR,ALPHA(l, l 0))

Examples:
WRITE(l, REC NAM, 33)
WRITE(4, REC NAM, REC)

17) DISPLAY statement (used to put output on the VT05 at a
certain row and column).

Genera I form:
DI SP LAY(row, column, variable)
Examples:

DtSPLAY(l I l I ·MESSAGE')
DISPLAY(I, J,2)
DI SP LAY(I, 8, ALPHA)

2-39

SECTION 3
A Programming Exercise

3-1

1•

QUESTION:

On this page is the definition of a program
you are to write. It is imperative you complete
writing the program before you look at th is
author's solution. It is also important that you
write the program during the same sitting in
which you study the previous two sections, for
the simple reason that prompt reinforcement
(through application) is the only way to
retain the thorough knowledge of DIBO L.
Feel free to use Sections l and 2 as reference.

YOU ARE TO WRITE A PROGRAM FOR THE ATHLETICS DEPARTMENT
OF A COLLEGE. STUDENT RECORDS ARE STORED ON DECTAPE
LOGICAL UNIT 15 IN A FILE CALLED 'STUREC', IN THE FOLLOWING FORMAT:
STUDENT
NUMBER

LAST
NAME

FIRST
NAME

CUMULATIVE
G .P.A.

SEX WEIGHT
(LBS)

HEIGHT
(FEET)

THE COACH WANTS A LIST OF ALL MEN ON CAMPUS WHO HAVE
A GRADE POINT AVERAGE ABOVE 85, WHO WEIGH OVER 170.00
POUNDS, AND WHO ARE OVER 5.75 FEET TALL. THE REPORT IS
TO LOOK AS SHOWN ON THE NEXT PAGE.

DON'T LOOK AT OUR SOLUTION UNTIL YOUHAVE COMPLETED
ALL WORK ON YOURS.

***

3-2

dec~system
CONSOLE AND PRINTER LAYOUT FORM

~ t-+-t-+-1-H-H-+-+-++++++++-t-+-+-t-1-+-t-+-+-++-++-++++-t+++-+-t-1-+-t-+-t-++-++++-++++-++-H-11--t-1-+-t-++~l++-t-t-++-++-++-t-H-+-t-++-++-tT++-++-++-i--H-+-t-++-tT++-++-++-++-H-ii--H-++++-r-t--t--r-++-++-H-1
2 r
!!
T
T .
1
~
j_i i
'j
j_
j_'
!- J 111 J! ' J i l U ' l Jllll__l_U
I Ii Iii I

111 I

'
Ii

'lll ' i

_;_·

1 I

i iJ_

'J. 'l• !

j_ l l l l j_j_ .
I Jj__i:

I I I I I i I i I

II I I I

' i I Ii

l '

•

I-+ T : ++-1-~ J_+

..L

ii'

'L l

J_
! !

...L

I. 111

'll

:t,_~.,";'!'.'.
' i
i
. .

I I

ili

'..l.

i 11: J l l I 1111

! ,I

! i

ii . '

!l!l!!I!!!

...

l JllJ_U_[_ J_
1

.!!!.!!!!!I!!!!!

. '

Ill

jJ_

T '.l
II

..l'

+:+-<

1:1

_j__j_

ITT

.T·T·

.T,

'·TT~' I'.

"TT

I I

ill

I I I I I I I I I I I I I I I II I

11111

11111 i I
11111111111111111

j_j_

T l ' TT : T : lTIT ' :

' I I

jj_ i

J_J_

1111

! ii l 11 !

llil 'l l

J_'

1111111

Ill

i I ! i U-Ll--L ~ ~+LLL '...Li...L_iJ_ ' 'j_ _j_ i 'J.

i I I iI I I I i i I ' I I

li.

Jj_ J

".'!.';

1 111111!1!11'!'111[111[![!1

'11

'Jl

... ,. .. j_

'_j_

Ii 111 11

1111''1!"111"

'J ' ' I Jj_ !
..... T ..

J
I

"'l'

, JI

11111

TTT ~ •Tl"T

IT;

I I.

I 111

..L

'1''
I

..L

l' I

'J.

I I'

..i

..11 J

_ill_

5.2.

..L

! .. I.

I I

t:m l _\
~ '

;

"""..LL

..L

•illjj_.jj_l_l._ll

•1!J_l_l_l1_L

Ii•

T TT

l
;

I ; '

_;_'
I

1:1-;-

,,,

j_~.1...L.}

!''

l;-'.TTT T; _1__1_ , ,
1

...L
1

r--~

_j__j_

..l.

-,-

l_l

; 11

JI
Ii I

! 1

~+-+-·-.:·---'l

11 l l J_
I•

i_;_

1
! I!' I

''_;_!

I I

irr i i
J_

1 I

'
1

I I

IIl I

!ii !

I
I
•1' J_
_l 1 1.1..l ...L .l..l. ..L..L..LLL

·r ;
J_
'

i 1I
I

_J_

_lj_

-1

j_J__lj_j_j_
1 1
1

.l .l

'I T

,-,--,-

.r
•TTTi

! 1 11 1

·1 l
' I ij_ 1_J_i

r::i:-1

·LlJ11'

1•1

1_j_ 1 1

-,-

1 _j_

.c.1

.l...L.l...L...L.

..l' .
I

--,-

-T

: TT

.l.J..l.l.J.

i"'':'

i ' i ; •

l
'

...l

i ' 1'

-,-

,_Li.1·LLJU_l_LI

ii''

:lT1_;__c

'TT I I I

Ll
1

"TT"T , -,-

J
'

-h
I

' l'
6•' I

: i lj_ i

,ll :

l~-

;

se. r TTTTT !

DEC7-(294)-1171-M573

_l11fu1

!!~l.ltli:

11..Lil ..

,53L"1·111•11"-""L

[. 1 11

111

J.
.

1 : II

...L

j_;

j
I I

NOTE: Variations in humidity may ca~se
]
inaccuracies in this form.Calculate 1·
dimensions of form from measurements shown not from ci1mens1ons
scaled from this chart.

riT2fJ!.tj5\6!700iN3'4 S!fil'e!91o!12!3i4l5!6!~1 23.i!s]tb!e[9!o!1•2Jill61\3!9lo!ili(J 4TSJ6f7ej91oi1 2:il4lsl617iifil~[1 213l4!5l6f7 ~il21314516 71819~1 2'314ls'61718191ol1234js'6j7 eili_i1213141516f71el91o11 23l4lslt>l-7l8Wi 2
0
1
2
T
3
T
4
T
5
!
6
!
7
I
8
9
I
10
11
12
]ill

3-3

START
RECORD

RECORD

RECORD
TAPEIN
STUNO,
LNAME,
FNAME,
GPA,
SEX,
LBS,
FEET,

;INPUT BUFFER FOR TAPE RECORDS
;Student Number
;Last Name
;First Name
;Cumulative Grade Point Average
;Sex (Mor F)
;Weight (XXX .X)
;Height (X .XX)

A3
A4
A9
AlO
AS
AlO
A7
A2
A9
A5
A7
A4

; Line printer Output Buffer
;Filler
;Student Number
;Filler
;Last Name
;Filler
;First Name
;Filler
;Cumulative GPA
;Fi lier
;Pounds
;Fi lier
;Feet

LPTBUF

,
LPNO,

,
LPLNAM,

,
LPFNAM,
I

LPG PA,
I

LP LBS,

'LPFEET
RECORD

D4
AlO
AlO
D2
Al
D4
D3

HEAD
1

D,A.T_E,

COLl
A4
A3, STU
Al9
A7, 'NAME'
Al7
A3, 'CUM'
AS
A6, 'WEIGHT'
A5
A6, 'HEIGHT'
1

RECORD

;First Iine of column heading
;Filler

COL2

;Second line of column heading
;Filler

A4
A3, 'NO.'
Al4
A4, LAST'
Al'2
A5, 'FIRST'
AS
A3, 'GPA'
A9
A5, (LBS)'
A6
A4, (FT)'
I

;Heading Line of Report
A37
;Filler
A5, 'DATE t....1'
_A8_, p
;Request date when pro.gram __ j_s
loaded XX/XX/XX
Al 8
;Filler
AlO, 'ATTN:COACH'

RECORD
LINECT; 02; 50
PROC

;BEGINNING OF PROCEDURE
SECTION
INIT(l, IN STUREC 15) ;Initialize the input tape
;Print report headings
CALL HEADER
XMIT(l ,TAPEIN,EOF)
;Read input tape
I I

REPT,

3-4

IF (SEX .NE. 1 M1 )
GO TO REPT
iF (GPA. LE .85)
GO TO REPT
IF (LBS. LE .1700)
GO TO REPT
IF (FEET .LE .575)
GO TO REPT
LPNO = STUNO
LP LNAM = LNAM E
LPFNAM = FNAME
LPGPA =GPA
LPLBS = LBS,

;**Test to determine

LPFEET =FEET I

;and lbs.

CALL PRINT
GO TO REPT

;Print the line
;Read another record

XMIT (6, LPTBUF)
INCR LINECT
CALL HEADER
RETURN

;Print the line
;Add one to line count
; Test if header is to be printed
;Return to instruction after last
;call

•xxx.x·

·x.xx·

PRiNT I

HEADER, IF (LINECT .LT .50)
GO TO EXIT
LINECT =
FORMS(6,0)
XMlT (6,HEAD)
FORMS(6, l)
XMIT (6,COLl)
XMIT (6,COL2)
FORMS(6,2)
RETURN
EXIT,
EOF I FINI (1)
STOP
END

;**if record shouid be
;**selected. If a test fai Is
;**read another record.
;Format print
;line by moving
;all fields to
;the appropriate print
;position. Edit feet

;Print every header after every
;50 Iin es
;Set line count to zero
;Skip to new page
;Print Header line
;Print blank line
;Print first header Iine
;Print second header Iine
;Print blank Iine
;Return to instruction after last cal I
;Rewind input file
;Return control to DIBOL monitor

3-5

SECTION 4
Advanced DIBOL Statements

4-1

This chapter explains the DIBOL statements which would be used by
experienced programmers to:
•

Increase system throughput by using print overlap.

•

Segment a program which no longer fits in available memory.

•

Access source files.

•

Do rounding and truncation.

An added complication in rounding is the sign of the number. If the
result of HOURS times RATE is negative, 500 must be subtracted
rather than added. The program to handle positive and negative
numbers is:

ROUNDING
In DIBOL, all decimal values are stored as integers. It is up to the
programmer to keep track of the implied decimal point and to do
rounding and truncation.

TAGl,
TAG2,

RECORD
HOURS, D5,04050RATE, D5,02535
SALARY,D6
TEMP, Dl 0
PROC
TEMP=HOURS*RATE
IF(TEMP.LT .0) GO TO TAGl
SALARY=(TEMP+500)/l 000
GO TO TAG2
SALARY=(TEMP-500)/l 000

For example:
Al I the statements in the procedure section can be replaced by the
following:

RECORD
;40.5 HOURS
HOURS, D5,04050
;$2 .535 PER HOUR
RATE,D5,02535
;IN DOLLARS AND CENTS
SALARY, D6
PROC
SALARY=(HOURS*RATE+500)/l 000

SALARY=(l-IOURS*RATE)#3
The form of this operator is:
decimal variable #n

Salary is set eqvoJ to 010267 which is actually $102 .67. The programmer added 500 to the results of HOURS times RATE in order to
round properly. The statement:

where n is a decimal constant or decimal variable in the range of 1
to 7. The decimal variable will be rounded and truncated n places.
There is no restriction to the number of #operators in a statement.
The # operator has higher priority than all other arithmetic operators;
therefore, rounding and truncation are performed before all other
arithmetic operations.

SALARY=HOURS*RATE/1000
would result in SALARY equalling $102.66, which would do truncation
without rounding.

4-2

The fo! lov1ing are some simple examples of # operator usage:
Example

Result

X=l 234#1
X=l 234#2
X=1234#3
X=5555#3

X=123
X=l2
X=l
X=6

QUESTION:

In the previous example, assume that SALARY
is three decimal places. What is the statement
that stores the product of HOURS and RATE in
SALARY?

QUESTION:

Whet is the value stored in SALARY in the
following:

SALARY=HOURS#l *RATE#3

***

5.
l.

ANSWER:

000120

QUESTION:

What is the value in HOURS and RATE after
rounding the fol lowing:
HOURS=2347
RATE=2347HOURS=HOURS#2
RATE=RATE#2

***
ANSWER:

SALARY=(HOURS*RATE)#2

QUESTION:

What is the value stored in SALARY in the
fol lowing example:

***
ANSWER:

SALARY=HOURS*RATE#3

CHARACTER CONVERSION

***

ANSWER:

012150 or $121.50. RATE is rounded and
truncated before being multiplied by HOURS.

QUESTION:

What statements will do the following: round
HOURS to the nearest hour and RATE to 'the
nearest dollar, multiply the result, and store in
SALARY (assume that SALARY is in dollars)?

***
ANSWER:

HOURS contains 23 and RATE contains minus
23.

The #operator is also used to convert a character to its equivalent
internal code and make that decimal number available to the program. When #precedes a variable, it is used to obtain the internal
code of the left-most character of the variable. Refer to Appendix A
of the COS 300 SYSTEM REFERENCE MANUAL for a table of internal
COS codes (COS codes are base 8).

I
4=3

QUESTION:

What is the value of J in the following example
if the internal code for 6 is 27 {base 8) or 23
decimal?

QUESTION:

***

RECORD
I, Dl , 6
J, D2
PROC
J=#I

10.

ANSWER:

J=#l(2,2)

QUESTION:

What is the value of Jin the following three
statements if the decimal code for A is 34, B
is 35, and C is 36?

***
ANSWER:

What statement will convert the second
character in, I?

J contains 23.

l,A3,'ABC'

J, D2
7.

QUESTION:

1
2
3

What is the value of J in the following case:
J=f #1

***

ANSWER:

J equals 1 • When the number sign fol lows the
variable, it is used for rounding and truncation.

QUESTION:

What is the value of J (the internal code for 7
is 24)?

***
ANSWER:

In statement 1, J is 34.
In statement 2, j is 35.
In statement 3, J is 36.

SOURCE FILES

RECORD
I, D2, 67

The main use of converting the internal code is when processing
source files. At run time, the user may specify up to seven source
files for iripuf fo a DTBOL program. The sfateme-nt:

J;-02
PROC
J=#I

INIT(n, SYS)

***
ANSWER:

PROC
J=#l(l, 1)
J=#l(2,2)
J=#l(3,3)

wi II open the first source file. The first record is read with an XMIT
statement. The first two characters in that record contain the line
number and may be converted to decimal with the following statements:

J equals 23. The left-most character in the
variable is converted.

4-4

LINE,
TEXT,
LINENO,

RECORD SRC
A2
Al20
RECORD
D4
PROC

if no such line number exists. The message
should be printed near the middle of a CRT
screen.
***
ANSWER:

RECORD
LINE,

SRC
A2
Al20
MSG
A2l, 1 LINE FOUND AT RECORD;
D3
Al 6, 1 IN SOURCE FILE'

SRCNO,

RECORD

LINEN 0= #LINE* 64+# LINE (2 I 2)

RECNO,
11,,

QUESTION:

!n the procedure section of the above examole.
fil I in the missing statements which would ' ,
initialize the source file and read the first
record.
***

ANSWER:

INIT(n,SYS)
XMIT(n, SRC, EOFRTN)

PROC
BEGIN,

LOOP,
When end-of-file is reached on a source file, the file should be
FINled. The next source file must be INITed before being read.
The INIT statement can be preceded by an ON ERROR statement
which will detect that no files are present. A source file can be
processed only once.

12.

QUESTION:

EOF,
MISSING,

Write a program which will read from one to
seven source fit es. Tile program witt dispfay:
LINE FOUND AT RECORD n IN SOURCE FILE n

DISPLAY(l, l, 1) ;CLEAR SCREEN
ON ERROR MISSING
iNIT(l, SYS)
REC NO=
INCR SRCNO
XMIT(l ,SRC,EOF)

iNCR RECNO
IF (#LINE*64+#LINE(2, 2). NE .3458)
GO TO LOOP
DISPLAY(l 0,25,MSG)
STOP
FINl{l)
GO TO BEGIN
DI spLAy (l 0, 30, I N 0 T F0 uND I)
STOP

The Monitor stores tabs in the source file as a single character with
an internal code of 61 decimal. When LISTing a program on the line
printer or terminal, the Monitor converts tabs into spaces.

if a line number of 3458 was found or will
display:

NOT FOUND

4-5

13.

QUESTION:

Write a DIBOL program which will detect tabs
in a source file.

***
ANSWER:

RECORD
TEXT,
RECORD

SRC
A2
120A1

LOOPl,

TAB,

;START LINE PRINTER
;PERFORM TASK

PROC
LOOP,

RECORD A
D3
PROC
TRAP SUB
FORMS(6,0)

LOOP,

INIT(l, SYS)
XMIT(l ,SRC,EOF)
I=
INCR I
IF (#TEXT(l).EQ .61) GO TO TAB
IF(l.EQ.120) GO TO LOOP
GO TO LOOPl

SUB,

IF(N .LT .500) GO TO LOOP

;WAIT FOR PRINTING
;TO TERMINATE

STOP
INCR N
IF(N .GT .500) RETURN
XMIT(6,A)
RETURN

In the preceding example, the line printer was started with the
FORMS statement. Some task was being performed. Since the
FORMS statement was preceded by a TRAP statement, the line
printer went to the statement specified by TRAP when it was free.
A line was XMITed to the line printer and the program then executed
a RETURN statement to resume the task. The XMIT statement in the
TRAP routine could have been preceded by another TRAP statement
if, when the line printer became free, the program were to go to a
different statement.

;FOUND A TAB

TRAP
Whenever reports are being printed, the entire computer is tied up
doing thaf task. Much better use of the computer could be obtainedif it were allowed to do some other task which does not use the line
printer. This is possible in DIBOL with the use of the TRAP statement.
Two tasks may be done concurrently. The line printer is given
priority and interrupts the other task whenever the line printer is free.

Note that both the task and the r-eport should be completed before the
program ends. If the task ends first, it waits in a loop for the
printing to complete.
NOTE

The following program prints numbers 1-500 on the line printer while
some other task is being performed:

For TD8E DEC tapes, print overlap wil I not take place if more than
78 characters are printed during one TRAP subroutine cal I. For
TC08 DECtapes, print overlap will not occur if more than 230
characters are printed.

4-6

14e

QUESTION:

Modifv the orevious example to print 50 lines
on on~ pag~ and then skip to a ~ew page.

lines. The heading and detail lines are 70
characters each.

***

***
ANSWER:
N,
LINE,

RECORD A
D3
RECORD
D2
PROC
TRAP SUB
FORMS(6,0)

ANSWER:
OLDSEQ,
LINE,
LPFLAG,
;START LINE PRINTER
;PERFORM TASK
SEQ,

LOOP,

SUB,
SUBl,
FORMS,

IF(N .LT .500) GO TO LOOP
STOP
INCR N
INCR LINE
IF(UNE .EQ .51) GO TO FORMS
TRAP SUB
XM!T(6,0)
RETURN
LINE=
TRAP SUBl
FORMS(6,0)
RETURN

I I

GETCRD,

CRDEOF I
15.

QUESTION:

Write a program which will read cards, verify
that columns l -5 are in numerical ascending
sequence (ignore out of order cards), and store
all 80 columns on a file named CARDS found
on logical unit 1. Concurrent with this task,
print a report. This report is already in print
format in a file named PRINTR on logical unit
2. Print 50 lines per page, a 1-line heading,
and two spaces between heading and detai I

RECORD PRINT
A70
RECORD
D5
D2
Dl
RECORD HDG
A70, I • • • '
RECORD CARD
D5
A75
PROC 2
INIT(3,C DR)
INIT(l ,OUTPUT, 'CARDS' 1)
INIT(2, INPUT PRINTR' 2)
TRAP HEADl
FORMS(6,0)

HEAD,

I
4-7

XMIT(3,CARD,CRDEOF)

IF(SEQ .LE .OLDSEQ) GO TO GETCRD
;IGNORE CARD
XMIT(l ,CARD)
OLDSEQ=SEQ
GO TO GETCRD
IF(LPFLAG .EQ .O) GO TO CRDEOF
; LPF LAG=O IF
;OUT OF CARDS BEFORE REPORT DON
STOP
TRAP HEADl
FORMS(6,0)
RETURN

HEADl I

LPT,

LPTEOF I

LINE=
TRAP LPT
FORMS(6,2)
RETURN
INCR LINE
IF(LINE .EQ .51) GO TO HEAD
XMIT(2, PRINT, LPTEOF)
XMIT(6, PRINT) ;RETURN TO LPT
;ON PRINTER DONE IF NO
;TRAP IS SPECIFIED.
RETURN
INCR LPFLAG ;PRINTING DONE
RETURN

The format of a CHAIN statement is:
CHAIN n
where n is a decimal variable in the range 0 to 7 and is the sequence
number of the program as specified in the RUN command.

16.

QUESTION:

What can be done when a program is too large
to fit in the available memory?

***
ANSWER:

The program may be separated into two or more
programs.

QUESTION:

How are these smaller programs linked
together?

CHAINING
17.
In the smallest COS 300 system, programs can be written which require up to 8K of core memory storage. Occasionally, a program is
written which exceeds this size and will not run with the avai Iable
memory. This problem may be overcome by a recently developed
feature in DIBOL called CHAINing. A large DIBOL program may be
separated into two or more smaller programs which are executed
sequentially. Each program is written and compiled separately.
These programs are linked together when they are run by saying:

***

18.
.RUN

ANSWER:

The programs are linked together at run time by
specifying the program names in the RUN
command.

QUESTION:

How can a DIBOL program be loaded from
another DIBOL program?

PROGO+PROGl + ••• +PROG7

***

The first program uses a CHAIN statement to load the next desired
program. Programs that are loaded by a CHAIN statement do not
have their data section cleared (unless specifically instructed), thus
permitting one program to pass information to another without saving
it on a data file.

ANSWER:

By using the CHAIN statement.

The RUN command specifies which programs wi II be used. For
example:
.RUN PROG+PROGA+PROGB

4-8

The CHAIN statement determines which program will be loaded and
run next. If, for example, the statement CHAIN 2 were inciuded in
PROG, it would terminate execution of PROG, load PROGB, and
begin execution of PROGB.

D5
RECORD,C
D4,0004

A15

PROC
LPTl=I
XMIT(6, LPT)
CHAIN 0
END

The data section is always cleared in a DIBOL program (except when
initial values are specified). However, the data section of any
program loaded by a CHAIN statement is not automatically cleared;
it wi 11 contain the values of the previous program. If some fields are
to be cleared, the program must specify:
RECORD

19.

QUESTION:

ANSWER:

Look at the fol lowing programs. In answering the questions, assume
that the RUN command is:

PROG increments I by 1 and if I does not equal
10, PROG CHAINs to PROGA which prints the
value of I and then CHAINs to PROG. When
I equals 10, the programs stop.

PROG+PROGA

20.
START
RECORD OUT
OUTl,
I,
NAME,
DUMMY,

QUESTION:

;PROGRAM PROG

***

RECORD
D5
A4, 'FRED'
A4
PROC
INCR I
IF(l,EQ .10) STOP
CHAIN 1
END

RECORD

Do the data sections have to be the same size
in each program?

START
RECORD LPT
LPTl I

What do PROG and PROGA do?

***

where the 11 ,C 11 means clear all the fields in this record that do not
have initial values.

RUN

;WORK AREA

21.

ANSWER:

No; the data section is only as large as needed.

QUESTION:

Do the data sections have to match each other
either by records or by fields?

***
ANSWER:

;PROGRAM PROGA

I
4-9

No; the programmer has complete freedom in
assigning the records, fields, and variable
names in the data sections. However, the information to be passed from one program to
another must be in the same relative location.
In the previous programs, for examole, I in
PROG could not be passed to I in PROGA if it

were not in the same relative location of the
data section.

22.

QUESTION:

What is the first statement executed in PROG?
In PROGA?

***

23.

ANSWER:

The first statement in the procedure section.

QUESTION:

What are the values of OUTl, I, NAME,
DUMMY, J, and K when PROG is run, when
PROGA is chained the first time, and when
PROG is chained the first time?

***
ANSWER:

OUTl
I
NAME
DUMMY

J
K

PROG
spaces

PRO GA

PROG

1
1

FRED
spaces
undetermined
undetermined

undetermined
undetermined
4
spaces

2
FRED
undetermined
undetermined
undetermined

File status is lost between CHAIN operations. Data files must be
FINled before transferring to another CHAIN. Files that are used
for input or output will present some problems since when they are
INITed in the next CHAIN, they will be at the beginning of the
file. The easiest solution to this problem is to use the data file as
an UPDATE file. When transferring to another CHAIN, FINI the
file, save the record number in some common area for use in the
next CHAIN or on return to the current CHAIN.

4-10

Oi70

APPENDIX A

ocrr'\Dl""I 01t-..1rw I"'\

".,...., t:'

INVOICE DATA ENTRY PROGRAM

0005
0010
0015
0020
0025
0030
0035
0040
0045
0050
0055
0060
0065
0070
0075
0080
0085
0090
0095
0100
0105
0110
0115
0120
0125
0130
0135
0140
0145
0150
0155
0160
0165

START

;INVENT - INVOICE DATA ENTRY

RECORD POET ;LINE ITEMS FOR LINE PRINTER(LPT)
A4
'
;ITEM NUMBER (PART NUMBER)
PINUM, A7
A5
'
PDESC,
A24 ;DESCRIPTION
A4
I
;QUANTITY ORDERED
PQO,
A2
A2
'
A2
;UNITS
PUNIT,
A2
I
A2
;QUANTiTY SHIPPED
PQS 1
Al5
I
;UNIT COST
PUNiTC, A6
Al
I
PEXTC, A9 ;EXTE~"1DED PRICE
BLOCK,X
A80
PDETL,

VI I ;J

l"\L.\...\,.11'1.l.J

0180
0185
0190
0195
0200
0205
0210
0215

A48
A5
A6
AS

PINVNO,

PINVD,

,
PADDRl,

0220

0225

PADDR2,

0230
0235
0240
0245
0250

RECORD PCUST ;FOR CUSTOMER LINE ON LPT
A8
PCUSTN, 05
;CUSTOMER NUMBER
A4
I
PSALMN, 02
;SALESMAN'S NUMBER
A9
I
;CUSTOMER'S ORDER NUMBER
PCUSTO, A5
A20
'
;DATE ORDERED
PDATEO, A8
A4
I
PDATES, A8
;DATE SHIPPED
A4
I
PSCODE, Dl
;SHIPPING CODE
I

0310
0315
0320
0325
0330
0335
0340
0345
0350

A-1

.CIDCT
II - 11\.U::
l=flk> I PT
II'\........, I
i i "\II L.. I """"""l'-

;INVOICE NUMBER
;DATE OF INVOICE

RECORD PADDRS ;ADDRESS LINES
A7
A30 ;LEFT-HAND SIDE
A8
A30 ;RIGHT-HAND SIDE
BLOCK PADRSA,X
A37

;CUSTOMER FILE

0255
0260
0265
0270
0275
0280
0285
0290
0295
0300
0305

I !I '4'--'1 IV

CUSTNO,
CUSTNM,
CUSTAl,
CUSTA2,
CUSTZP I
CUSTSN,
CUSTDC,
CUSTTX,
CUSTSC,

CXKEY,
CXPTR,

RECORD CUSTR ;DATA RECORD
05
;CUSTOMER NUMBER
A30 ;CUSTOMER NAME
A25 ;ADDRESS LINE l
A25 ;ADDRESS LINE 2
A5
;ZIP CODE
02
;SALESMAN CODE
02
;DISCOUNT%
Dl
;TAX%
Dl
;SHIP CODE
010 ;YEAR-TO-DATE TOTAL
(NOT USED IN THIS PROGRAM)
RECORD CUSTX ;INDEX RECORD
05
;KEY (CUSTOMER CODE)
02
;RECORD POINTER

;PART FILE

PARTNO,

RECORD PARTR ;DATA RECORD
A7
;PART NUMBER

0355
0360
0365
0370
0375
0380
0385
0390
0395
0400
0405
0410
0415
0420
0425
0430
0435
0440
0445
0450
0455
0460
0465
0470
0475
0480
0485
0490
0495
0500
0505
0510
0515
0520
0525
0530
0535

PARTDS,
PARTUT,
PARTUC,

A30
A2
D5

PXKEY,
PXPTR,

RECORD PARTX ;INDEX RECORD
A7
;KEY (PART NUMBER)
D2
;POINTER

0540
0545
0550
0555
0560
0565
0570
0575
0580
0585
0590
0595
0600
0605
0610
0615
0620
0625
0630
0635
0640
0645
0650
0655
0660
0665
0670
0675
0680
0685
0687
0690
0695
0700
0705
0710

;DESCRIPTION
;UNIT TYPE (EA, DZ, BX, ETC.)
;UNIT COST

;TEMPORARY FILE TO HOLD LINE ITEMS DURING ENTRY
OF INVOICE

TMPITM,
TMPQO,
TMPQS,
TMPUC,
TMPUNT,
TMPDES,

RECORD TEMPR ;DATE RECORD
A7
; ITEM (PART) NUMBER
D2
;QTY ORDERED
D2
;QTY SHIPPED
D5
;UNIT COST
A2
;UNIT
A30 ;DESCRIPTION

;FILE TO HOLD TRANSACTIONS

TRCODE,
TRCUST,
TRCORD,
TRDATE,
TRSALN,

RECORD TRANS
Al
;RECORD CODE (H=H EADER, D=DET Al L)
D7
;CUSTOMER CODE
D5
;CUSTOMER'S ORDER NUMBER
D6
;DATE SHIPPED
D2
;SALESMAN'S NUMBER

TRITM,
TRQO,
TRQS,
TRUC,

BLOCK,X
Al
A7
;HEM (PART) NUMBER
D2
;QTY ORDERED
D2
;QTY SHIPPED
D5
;UNIT COST

;FOR KEYBOARD INPUT

0715

RECORD KBDREC

A-2

KBDIN,
KBDCH,

A30
BLOCK,X
30Al

CURSOR,
EOS,
EOL,
BEEP,
HOME,

BLOCK
D2,00
D2,01
D2,02
D2,25
D2,03

ED52,
ED32,
EDATE,

BLOCK
;EDIT WORDS
A9,
A6, 1XXX
AB, 1 XX/XX/XX 1
BLOCK
A5
A23
A25
A28
A30

;CONSTANTS

SPC5,
SPC23,
SPC25,
SPC28,
SPC30,

;SCRATCH

AX9,
DX7,
TEMP,

BLOCK
Al
A2
A4
A6
A9
D7
D2

CIN,
CINX,
CINL,

BLOCK
D2
D2
D2

COL,

;WORK
;CURRENT LINE NUMBER
;CIN+5
;LAST LINE NUMBER IN CURRENT
INVOICE
;EXPECTED COLUMN FOR INPUT

AXl I
AX2,
AX4,

M6.,

;CURSOR CONTROLS
;TO POSITION CURSOR
;TO CLEAR SCREEN
;TO CLEAR LINE
;TO BEEP
;TO HOME CURSOR

·xx,xxx .xx·
.xx·

0720
0725

INVNO,
NOFIND,

D5
Al

0730
0735
0740
0745
0750
0755
0760
0765
0770
0775
0780

DATORD,
TODAY,
TODAYD,
I,
ex,
PX,
TOTPRC,
DISCA,
TAXA,
PAYA,
TCHAR,

A8
A8
D6,D
D2
D3
D3
D7
D7
D7
D7
D2

0785
0795
0800
0805
0810
0815
0820
0825
0830
0835
0840
0845
0850
0855

LINE,

;CURRENT INVOICE NUMBER
;NON-BLANK IF CUSTOMER OR
PART NOT FOUND
;DATE OF ORDER
;TODAY 1 S DATE (MM/DD/YY)
;TODAY 1 S DATE (MMDDYY)
;INDEX
;INDEX TO CUSTOMER FILE
;INDEX TO PART FILE
;TOTAL INVOICE PRICE
;DISCOUNT AMOUNT
;TAX AMOUNT
;PAY THIS AMOUNT
;TERMINATING CHARACTER FOR
'ACCEPT'
;LINE COUNT FOR PRINTER

ITMTAB,
CUSTAB,

BLOCK
llA7
11 D5

;ROUGH TABLES FOR INDEX FILES
;ITEM TABLE
;CUSTOMER TABLE

0905
0910
0915
0920
0925
0930
0935
0940
0945
l 000

i OOi
1002

i 003
1004
1005
l 010
l 015
i020
1025
1030
1035
1040
1045

;HEADINGS FOR CRT
BLOCK
A3
A4, 1 ITEM 1
A5
Al 1' I DESCRIPTION·
Al4
A3, 1 QTY 1
A3

l 055
l 060
1065

A41 1 UNH 1 •

1070

0865
0870

A3
A3, 1 QTY 1
A3
A4, 1 UNIT 1
A7
AS, 1 PRICE 1
A4
A2, 1 N0 1

1075
l 080
1085
l 090
l 095
1100
1105
1110

0880
0885
0890
0895
0900

.***************
'
;SOURCE FiLE ihiVEN2
. * * *** * ** * * * * * * *
I

;CREATE ROUGH CUSTOMER INDEX

INIT (7, i~'1, 'CINDEX 1 , 7)

RUFCSl I

1050

006{)

0875

HEADl,
H EAD2,
PROC6

A30
A5, 1 0RDERi
AS
A4, I SH IP 1
A3
A4, ·cosT·
BLOCK,X
A72
A60
;INVENT----- INVOICE DATA ENTRY

A-3

RUFCS5,

CX=
l=l
INCR ex
XMIT (7, CUSTX, RUFCS5)
IF (CX(3,3).NE.l) GO TO RUFCSl
;IS TH IS
THE lST' 11 TH I 21 ST I ETC RECORD
CUSTAB(l)=CXKEY
; SAVE EVERY l OTH
CUSTOMER IN CUSTAB
INCR I
GO TO RUFCSl
CUSTAB(l)=99999
FIN I (7)

;CREATE ROUGH PART INDEX

RFITMl,

INIT (9, iN, 1 PINDEX;' 9)
l=l
PX=
INCR PX
XMIT (9, PARTX, RFITM5)

1115
1120
1125
1130
1135
1140
1145
1150
1155
1160
1162
1165
1170
1175
1180
1185
1190
1195
1200
1205
1210
1215
1220
1225
1230

RFITM5,

IF (PX(3,3).NE.l) GO TO RFITMl ;IS THIS THE
l ST, l lTH, 21 ST, ETC. RECORD
ITMTAB(l)=PXKEY ;SAVE EVERY lOTH ITEM IN
ITMTAB
INCR I
GO TO RFITMl
ITMTAB(I)='] ] ] ] ] ] ] I
FINI (9)

1290
1295
1300
1305
1310
1315
1320
1325
1330
1335
1340
1345
1350
1355
1360
1365
1370
1375
1380
1385
1390
1395
1400
1405
1409
1410
1415
1420
1425

TODAY=TODAYD, EDATE
;CREATE EMPTY 1 TEMP 1 FILE
;(TEMP HOLDS LINE ITEMS DURING ENTRY OF INVOICE)

CLEAN,

1=20
INIT (l ,OUT, 'TEMP', l 0)
XMIT (l, TEMPR)
l=l-1
IF (I .GT .00) GO TO CLEAN
FINI (1)

;OPEN UP ALL FILES
INIT (l, UPDATE, 1 TEMP 1 , l O)
INIT (2,0UT-, 1 ITRANS 1 , 11)
INIT (3,KBD)
IN IT (4, TTY)

1235

!NIT (5, LPT) ·

1240
1245
1250
1255
1260
1265
1270
1275
1280
1285

INIT (6, IN, 1CUSTFL 1 ,6)
INIT (7, IN, 1 CINDEX 1 ,7)
INIT (8, IN, 1 PARTFL 1 ,8)
INIT (9,IN, 1 PINDEX 1 ,9)

1430
1435
1440
1445
1450
1455
1485
1487

;ASK IF FORM IS IN PRINTER
ASKl,

XMIT (4,' INVOICE FORM IN PRINTER?')
XMIT (3, KBDREC)
IF (KBDIN (1, 1) .NE. 'Y') GO TO ASKl

A-4

;PUT OUT THE DUMMY ENTRIES TO TEST FORM POSITION

ASK2,

FORMS (5,0)
;TOP-OF-FORM
Pl NVN0=' 99999'
PINVD='XX/XX/XX'
PCUSTN=9999999
PSALMN=99
PCUST0= 1XXXXX 1
PDATE0= 1XX/XX/XX 1
PDATES=PDATEO
PSCODE=9
PINUM= 1XXXXXXX 1
PDESC=' xxxxxxxxxxxxxxxxxxxxxxxx I
PQ0=99
PUNIT='XX'
PQS=99
PUN ITC=' 999. 99'
PEXTC= 1 99, 999.99'
XMIT (5, PINCH D)
FORMS (5, 11)
XMIT (5, PCUST)
FORMS (5,2)
XMIT (5, POET)
LINE=l 6
CALL TOPAGE
XMIT (4,i•fORM LINED UP?')
XMIT (3, KBDREC)
; 1 Y 1 IS TYPED WHEN
FORMS ARE LINED UP
IF (KBDIN (1 , l) .NE. 'Y') GO TO ASK2

;ASK FOR FIRST INVOICE NUMBER
ASK3,

XMIT (4, "WHAT IS FIRST INVOICE NUMBER?')
XMIT (3, KBDREC)
IF (KBDIN(6,30).NE .SPC25) GO TO ASK3
ON ERROR ASK3

1490
i 495
1500
1505
1510
1515
1520
1525
1530
1535
1 &:.Al'\
I .J"TV

1545
1 LI'\&:.
IVV.J

1607
1610
1612
1615
1620
1625
1630
1635
1640
1645
1650
1655
1660
1665
1670
1675
1680
1685
1690
1695

INVNO=KBDIN(l ,5)

i725
17'lf\
IF vV

,·*****************************************************
;START A NEW INVOICE
·*****************************************************
I
NEWINV,

DISPLAY (1, 1, EOS)

1735
1740
1745
1750
1755
1760
1762
1765
1770
1775
1780
1785
1790
1795
1800
1805
1810
1815
1820
1825
1830
1835
1840
1842
1843
1845
1850
1855
1860
1865
1870

;CLEAR SCREEN

DISPLAY (l, l , 1 CUSTOMER NO:')
CINX=l
rru
=l A
'-''-' ..... -.
CALL GETKBD
!F {KBD!N(6,30).NE.SPC25) GO TO BADCUS
ON ERROR BADCUS
CUSTNO=KBDIN(l, 5)
IF (CU ST NO. LT .1) GO TO BADCUS
CALL GETCUS
IF (NOFIND.NE. 1 1 ) GO TO NOCUST
TRCUST=CUSTNO
;GET CUSTOMER'S ORDER NUMBER
DISPLAY (1,21, ~cusTOMER ORDER: 1 )
COL=37
CALL GETKBD
TRCORD=KBDI N (1, 5)
;GET DATE ORDERED
DISPLAY (1,45, 'DA TE')
COL=50
CALL GETKBD
DATORD=KBDIN (l, 8)

i700
1705
1710
1715
1720

;GET SALESMAN'S CODE
DISPLAY (1,59, 'SALESMAN 1 )
AX2=CUSTSN

A-5

l'~INV5A,

Di SPLAY (i ,68,AX2)
COL=70
CALL GETKBD
IF (KBDIN .EQ. SPC30) GO TO NINV5C
CALL GETD2A
IF (KBDIN(3,30).NE.SPC28) GO TO BADSN
CUSTSN=KBDIN (I, 2)
IF (CUSTSN .LT .1) GO TO BADSN
AX2=CUSTSN
DISPLAY (1 ,68,AX2)
DISPLAY (1,70,EOL)

N!NV5C;

TRSALN=CUSTSN

;ALL IS WELL WITH INITIAL LINE -- PUT OUT HEADINGS
DISPLAY (3, l ,HEADl)
DISPLAY (4, l ,HEAD2)
CINL=
TOTPRC=

·*****************************************************
I
;START NEW LINE
·*****************************************************
I
; GET ITEM NUMBER
NINV7,
NINV8,

INCR CINL
CIN=CINL
AX2=CIN

CINX=CIN+5
DISPLAY(CINX, 1AX2)
DISPLAY (CINX,3,EOL)

1875

DrSPLAY (C!NX,4,CURSOR)

1880
1885
1890
1895

COL=4
CALL GETKBD
IF (KBDIN(8,30).NE.SPC23) GO TO BADINO
IF (KBDIN(l ,7).EQ. 'TOTAL') GO TO TOTALI

1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995

IF (KBDIN(l, l ).EQ • 1 - 1 ) GO TO CORECT
IF (KBDIN{l ,7).EQ .'RESTART') GO TO NEWINV
IF (CINL.GT.8) GO TO TUMANY
TMPITM=KBDIN (1, 7)
PARTNO=TMPITM

2090
2095
2100
2105
2110
2115
2120
2125
2135
2145
2150
2155
2160
2165
2170
2175
2180
2185
2190
2192
2193
2195
2200
2205
2210
2215
2220

CALL GETITM
IF (NOFIND .NE. 1 1 ) GO TO NOPART
DISPLAY (CINX, 13, PARTDS)
TMPDES=PARTDS
;GET QTY ORDERED
NINV9,

DISPLAY (CINX,38,CURSOR)
COL=38
CALL GETD2
IF (KBDIN(l ,2).EQ. I ')GO TO BADQO
TMPQO=KBDIN(l ,2)
AX2=TMPQO
DISPLAY (CINX,38,AX2)

2000
2005
2010
2015
2020
2025
2030
2035

2040
2045
2050
2055
2060
2065
2070
2075
2080
2085

;DISPLAY UNITS
DISPLAY (CINX,45,PARTUT)
TMPUNT=PARTUT

;GET QTY SHIPPED
NINVlO, DISPlAY (C INX,51 ,CURSORf
COL=51
CALL GETD2
IF (KBDIN{l,2).EQ. I') GO TO BADQS
TMPQS=KBDIN (1, 2)
AX2=TMPQS
DISPLAY (CINX,51,AX2)
AX6=PARTUC, ED32
DISPLAY (CINX,55,AX6)

A-6

TMPUC=PARTUC
AX9=PARTUC+TMPQS, ED52
DISPLAY (CINX,64,AX9)
;INPUT OF LINE COMPLETE
WRITE (1, TEMPR, CIN)
TOTPRC=PARTUC*TMPQS+TOTPRC
GO TO NINV7
;TOTAL OUT THE INVOICE
TOTALI, CINL=CINL-1
DISPLAY {CINX, 1,EOL)
DISPLAY (15,47, 'TOTAL PRICE')
AX9=TOTPRC, ED52
DISPLAY (15,60,AX9)
;COMPUTE & DISPLAY DISCOUNT, IF ANY
IF (CUSTDC .EQ .00) GO TO TOTAL3
DISPLAY {16,47,'DISCOUNT')
AX2=CUSTDC
DISPLAY (16, 56,AX2)
DI p LA (16 I 58, I% I)
DISCA=(TOTPRC*CUSTDC+50)/100

2225

AX9:=DLSCA,ED52

2230
2235
2240
2245
2250
2255
2260
2265
2267
2268

DISPLAY {16,60,AX9)
DX7=TOTPRC-DISCA
DISPLAY (16,60,AX9)
GO TO TOTAL4
TOTAL3,

DX7=TOTPRC
DISCA=

;COMPUTE & DISPLAY TAX, IF ANY

2270
2275
2280
2285
2290
2295
2300
2305
2310
2315

TOTAL4,

DiSPLAY (17,47,'TAX 1 )
IF (CUSTTX .EQ .O) GO TO TOTALS
AXl=CUSTTX
DISPLAY (17,51,AXl)
DISPLAY (15, 52, 1 % 1 )
TAXA=(DX7*CUSTTX+50)/l 00
AX9=TAXA, ED52
DISPLAY (17,60,AX9)
PAYA=DX7+TAXA
GO TO TOTAL6

2675
2680
2685
2690
2695
2697
2698
2700
2705
2710
2715
2720
2725
2730
2735
2740
2745
2750
2755
2760
2765
2770
2775
2776
2777
2778
2779
2780
2785
2790
2795
2800
2805
2810
2815
2820
2825
2830

'>'l'>n

L.\JL.V

2325

TOTALS,

'>'l"ln

r..uvu

2335
2340
2345
2350
2600
2601
2602
2603
2604
2605
2610
2615
2620
2625
2630
2635
2637
2638
2640
2645
2650
2655
2660
2665
2670

TAXA=
PAYA=DX7

TOTAL6,

DISPLAY (19,44, 1 PAY THIS AMOUNT')
AX9=PAYA, ED52
DISPLAY (19,60,AX9)
I. * * * * * * * * * * * * * * *
;SOURCE FILE INVEN3
I. * * * * * * * * * * * * * * *

iPR!NT OUT THE INVOICE
PINVNO=INVNO
PINVD=TODAY
XMIT (5, PINCH D)
FORMS (5,3)
;PRINT NAME AND ADDRESS
PADDRl =CUSTNM
CALL PRNTIF
PADDR1=CUSTA1
CALL PRNTIF
PADDRl =CUSTA2
CALL PRNTIF
PADDRl (1, 19)=

A-7

PADDRJ (20, 24)=CUSTZP
CALL PRNTIF
FORMS (5,4)
;PRINT GENERAL INFORMATION LINE
PCUSTN=CUSTNO
PSALMN=CUSTSN
PCUSTO=TRCORD
PDATEO=DATORD
PDATES=TODAY
PSCODE=CUSTSC
XMIT (5, PCUST)
FORMS (5, 2)
TRCODE='H'
TRDATE=TODAYD
XMIT (2, TRANS)
TRCODE='D'
l=l
LINE=l 5
PDETL=
;PRINT INVOICE ITEMS
PLOOP,

READ (l, TEMPR, I)
PINUM=TMPITM
PDESC=TMPDES
PQO=TMPQO
PQS=TMPQS
PUNIT=TMPUNT
PUN ITC=TMPUC, ED32
PEXTC=TMPUC*TMPQS, ED52
XMIT (5, PDET)
INCR LINE

2835
2840
2845
2850
2855
2860
2865
2866
2880
2885
2890
2895
2900
2905
2910
2915
2920
2925
2927
2928
2930
2935
2940
2945
2950
2955
2960
2962

3007
3008
3009
3010
3011
3012
3013
3015
3020
3025
3030
3035
3040
3045
3050
3055
3060
3065
3070
3075

TRITM=TMPITM
TRQO=TMPQO
TRQS=TMPQS
TRUC=TMPUC
XMIT (2, TRANS)
l=l+l
IF (I .LE .CINL) GO TO PLOOP
CALL BOTPAG
;TOTAL PRICE LINE
PDETL=
PDETL (59,70)='TOTAL PRICE'
PEXTC=TOTPRC, ED52
XMIT (5, POET)
INCR LINE
;CUSTOMER DISCOUNT LINE

3080

IF (CUSTDC .EQ .00) GO TO PLOOP2
PDETL(59, 70)= 1 DISCOUNT XX%'
PDETL(68, 69)=CUSTDC
PEXTC=DISCA, ED52
XMIT (5, POET)
INCR LINE

3085
3090
3095
3100
3105
3110
3115
3120
3125
3130
3135
3140
3145
3150
3155
3160
3165

;CUSTOMER TAX LINE

2963
2965
2970
2975
2980
2985
2990
2995
3000
3005

PLOOP2,

PLOOP3,

IF (CUSTTX .EQ .0) GO TO PLOOP3
PDETL(59,70)= 1 TAX X%
PDETL(63, 63)=CUSTTX
PEX TC= TAXA I ED52
XMIT (5 I POET)
INCR LINE
FORMS (5, l)

A-8

;CUSTOMER NET PRICE LINE
POET=
PDETL(21,35)= 1 PAY TH IS AMOUNT'
FORMS(5,-2)
;DOUBLE WIDTH CHARACTERS
XMIT (5, POET)
POET=
PEXTC=PAYA, ED52
XMIT (5 I POET)
LINE=LINE+3
CALL TOPAGE
;WAIT FOR OPERATOR
DI SP LA y (20 I 1, O)
CALL GETKBD
INCR INVNO
IF (KBDIN(l ,4) .NE. 1 END 1 ) GO TO NEWINV
FINI (l)
FINI (2)
FINi {3)
FIN I (4)
FINI (5)
FINI (6)
FINI (7)
FINI (8)
FIN I (9)
STOP
;GET READY TO CORRECT A LINE
CORECT, CINL=CINL-1
KBDIN (l, 29)=KBDIN (2, 30)
CALL GETD2A
IF (KBDIN (l, 2) .EQ. I I) GO TO CORCT2
C IN=KBDIN (l, 2)
IF (CIN .EQ .0) GO TO CORCT2
IF (CIN .GT .CINL) GO TO CORCT4

3170
3175
3180
3185
3190
3195
3200
3205
3210
3215
3220
3225
3230
3235
3300
3301
3302
3303
3304
3310
3311
3315
3320
3325
3330
3335
3336
3340
3345
3350

DiSPLAY (CINX, l ,EOL)
READ (1, TEMPR, C It-~)
TOTPRC=TOTPRC-TMPUC*TMPQS
GO TO NINVB
CORCT2,
CORCT3,

CORCT4,

DISPLAY (20, l, BEEP)
DISPLAY (20, l ,'BAD LINE NUMBER')
CALL ERAW8
GO TO NINV7
DISPLA.Y (20, 1 ,BEEP)
DISPLAY (20, l, 1 LINE NUMBER TOO BIG')
GO TO CORCT3

. * * * * * * * * * * * * * * *
;SOURCE FILE INVEN4
,. * * * * * * * * * * * * * * *
I

;GO TO TOP OF NEXT PAGE ON THE FORM
TOPAGE, FORMS (5,42-LINE)
LINE=
RETURN
;GET TO BOTTOM OF PAGE
BOTPAG,

1=15-1
IF (I • LE .0) RETURN
FORMS (5, l)
LINE=LINE+l
RETURN

3355
3360
3362
3365
3370
3375
3380

;GET AN ITEM FROM THE KEYBOARD
;(IF TCHAR IS CTRL/U (21), CLEAR INPUTTED ITEM &
ACCEPT IT AGAtN
GETKBD, KBDIN=
ACCEPT (TCHAR, KBDIN)
IF (TCHAR .NE .21) RETURN

A-9

3385
3390
3395
3400
3405
3410
3415
3420
3425
3430
3435
3465
3470
3475
3480
3485
3490
3495
3497
3498
3500
3505
3510
3512
3513
3515
3520
3525
3530
3535
354{)
3545
3550
3555
3560
3565
3570
3575

DISPLAY (CJNX; COL,EOL)
GO TO GETKBD
RETURN
;GET A ONE OR TWO DIGIT NUMBER FROM KEYBOARD
GETD2,
GETD2A,

GETD2X,

CALL GETKBD
IF (KBDIN(3,30) .NE.SPC28) GO TO GETD2X
ON ERROR G ETD2X
TEMP=KBDIN(l ,2)
IF (TEMP. LT .0) GO TO GETD2X
RETURN
KBDIN=
RETURN

;GET A CUSTOMER RECORD
GETCUS,

CX=2

;FIND ROUGH INDEX (\VITHIN l 0)
GTCUSl I
IF (CUSTAB (CX) .GT .CUSTNO) GO TO GTCUS2
INCR ex
GO TO GTCUSl
;GET EXACT INDEX
GTCUS2,
CX=(CX-2)*10
GTCUS3,
INCR ex
READ (7,CUSTX,CX)
IF (CXKEY .EQ .CUSTNO) GO TO GTCUS5
IF (CXKEY .LT .CUSTNO) GO TO GTCUS3
NOffN£r- 1 X1 ;tNVAltD CUSTOMER NO
RETURN
GTCUS5,
CX=CXPTR
;MATCH ON CUSTOMER NO
READ (6 1 CUSTR;CX)
NOFIND=
RETURN
;GET A PART RECORD

3580
3585
3587
3588
3590
3595
3600
3605
3610
3615
3620
3625
3630
3635
3640
3645
3650
3655
3660
3665
3670
3675
3680
3685
3690
3695
3700
3705

3/lO
3715
3720
3725
3730
3735
3740
3745
3750
3755

GETITM,

3760
3765
3770
3775
3780
3785
3790
3795
3800
3805
3810
3815
3820
3825
3830
3835
3840
3845
3850

PX=2

;FIND ROUGH INDEX ('NITHIN 10)
GTITMl,
IF (ITMTAB (PX).GT .PARTNO) GO TO GTITM2
INCR PX
GO TO GTITMl
GTITM2,
PX=(PX-2)*10
GTITM3,
INCR PX
READ (9,PARTX,PX)
IF (PXKEY .EQ .PARTNO) GO TO GTITM5
IF (PXKEY .LT .PARTNO) GO TO GTITM3
NOFIND= 1 X 1
;INVALID PART NO
RETURN
GTITM5,
PX=PXPTR
;MATCH ON CUSTOMER NO
READ (8, PARTR, PX)
NOFIND=
RETURN

385~

;PRINT ONE OR TWO ADDRESS LINES
PRNTIF I

PRNTFl I

PRNTF2, -

3860
3865
3870
3875
3880
3885
3890
3a95
3900
3905
3910
3915
3920
3925
3930
3935
3940
3945

IF (PADDR2 .EQ .SPC30) GO TO PRNTFl
XMIT (5, PADDRS)
RETURN
IF (PADDRl .EQ .SPC30) GO TO PRNTF2
XMIT (5, PADRSA)
RETURN
FORMS (5, l)
RETURN

I·*****************************************************
;ERROR ROUTINES
I·*****************************************************
;BAD ITEM NUMBER

BAD I NO I

DISPLAy (20, l, BEEP)
DISPLAY (20, l, 'TOO MANY CHARACTERS')

A-10

CALL ERAW8
GO TO NINV8
;BAD CUSTOMER NUMBER
BADCUS,

DISPLAY (20,l,BEEP)
DISPLAY (20, l, 'MUST BE 5-DIGIT NUMERIC')
CALL ERAW8
GO TO NEWINV

;CUSTOMER NOT FOUND ON FILE
NOCUST,

DISPLAY (20, l ,BEEP)
DISPLAY (20, l, 'CUSTOMER NOT FOUND')
CALL ERAW8
GO TO NEWINV

;PART NOT FOUND ON FILE
NO PART I

DI SP LAy (20, l, BEEP)
DI SP LAy (20, l, I PART NOT FOUND')
CALL ERAW8
GO TO NINV8

;BAD QTY SHIPPED
BADQS,

DISPLAY (20, l, BEEP)
D.ISPLAY (20, l, 1MUST BE ONE OR TWO DIGITS-'-)CALL ERAW8
DISPLAY (CINX,COL,EOL)
GO TO NINVlO

;BAD QTY ORDERED
BADQO

DISPLAY (20, l, BEEP)
DISPLAY (20, 1, 'MUST BE ONE OR TWO DIGITS')
CALL ERAW8
DISPLAY (CINX,COL, EOL)

3950
3955
3960
3965
3970
3975
3980
3985
3990
3995
4000
4005
4010
4015
4020
4025
4030
4035
4040
4045
4050
4055
4060
4065

GO TO NiNV9

;BAD SALESMAN'S NUMBER
BADSN,

DISPLAY (20,l,BEEP)
DISPLAY (20, l, 'BAD SALESMAN NUMBER')
CALL ERAW8
DI SP LAy (l , 70 I EO L)
GO TO NINV5A
;BAD SALESMAN 1 S !~UMBER
;TOO MANY ITEMS
TUMANY, DISPLAY (20, l ,BEEP)
DISPLAY (20, l, 1 TOO MANY LINES')
CALL ERAW8
GO TO NI NV8
;WAIT FOR A CHARACTER TO BE TYPED
ERAW8,

CALL GETKBD
DISPLAY (20, 1,EOL)
RETURN

END/N

A-11

APPENDIX B

Crossing of Flowlines - Flo\•tlines may cress; this means they
have no logical interrelation. Example:

STANDARD FLOWCHART SYMBOLS

SYMBOLS
l•

Input/Output Symbol - Represents an input/output function
(1/0), that is, the making available of information for processing (input), or the recording of processed information
(output).

LJ
2.

Every flow Iine entering and leaving a junction shou Id have
arrowheads near the junction point. Example:

Process Symbol - Represents any kind of processing function;
for example, the process of executing a defined operation or
group of operations resulting in a change in value, form or
location of information.

D
3.

Junction of Flowlines - Two or more incoming flowlines may
join with one outgoing flowline. Example:

Flowline Symbol - Represents the function of linking symbols.
It tndkotes the sequence of ovoHoble rnformotion and executable o.perations.

Comment, Annotation Symbol - Represents the annotation
function, that is, the addition of descriptive comments or
explanatory notes as clarification. The broken line is
connected to any symbol at a point where the annotation is
meaningfuf by extending tne broken fine in whatever fashion
is appropriate.

---L_
B-1

SPECIALIZED SYMBOLS
Specialized 1/0 Symbols may represent the 1/0 function and, in
addition, denote the medium on which the information is recorded
or the manner of hand Iing the information or both.
l•

Online Storage Symbol - Represents an 1/0 function
utilizing any type of on line storage; for example, magnetic
tape, magnetic drum, magnetic disk.

Punched Card Symbol - Represents an 1/0 function in which
the medium is punched cards.

Magnetic Tape Symbol - Represents an 1/0 function in
which the medium is magnetic tape.

The fol lowing symbols may be used to represent a deck of
cards or a file or cards.
Deck of Cards Symbol. The symbol shown below represents
a collection of punched cards.

Punched Tape Symbol - Represents an 1/0 function in which
the medium is punched paper tape.

File of Cards Symbol. The symbol shown below represents a
collection of related punched card records.

Magnetic Disk Symbol - Represents an 1/0 function in which
the medium is magnetic disk~

B-2

Core Symbol - Represents an 1/0 function in which the
medium is magnetic core.

10.

Offl ine Storage Symbol - Represents the function of storing
information offiine, regardiess of the medium on which the
information is recorded.

11 •

Communication Link Symbol - Represents information
transmitted by a telecommunication link.

Document Symbol - Represents an 1/0 function in which the
medium is a printed document.

L-J
8.

Manual Input Symbol - Represents an input function in
which the information is entered manually at the time of
processing; for example, by means of on line keyboards,
switch settings, push buttons.

SPECIALIZED PROCESS SYMBOLS
Specialized process symbols may represent the processing function
and, in addition, identify the specific type of operation to be
performed on the information.

l .

Display Symbol - Represents an 1/0 function in which the
information is displayed for human use at the time of processing, by means of on line indicators, video devices,
console printers, plotters, and so forth.

0
B-3

Decision Symbol - Represents a decision or switching-type
operation that determines which of a number of alternative
paths is to be followed.

Predefined Process Symbol - Represents a named process
consisting of one or more operations or program steps that are
specified elsewhere; for example, subroutine or logical unit.
Elsewhere means not this set of flowcharts.

D
3.

Merge Symbol - Represents the combining of two or more
sets of items into one set.

Extract Symbol - Represents the removal of one or more
specific sets of items from a single set of items.

Sort Symbol - Represents the arranging of a set of items into
a particular sequence.

Col late Symbol - Represents merging with extracting, that
is, the formation of two or more sets of items from two or more
other sets.

Preparation Symbol - Represents modification of an instruction or group of instructions which change the program
itself; for example, set a switch, modify an index register,
or initialize a routine.

Manual Operation Symbol - Represents any offline process
geared to the speed of a human being, without using
mechanical aid.

Auxiliary Operation Symbol - Represents an offline operation
performed on equipment not under direct control of the central
processing unit.

D
B-4

ADDITIONAL SYMBOLS

l•

Connector Symbol - The symbol shown below represents an
exit to or an entry from another part of the flowchart. It is a
junction in a line of flow. A set of two connectors is used to
represent a continued flow direction when the flow is broken
by any limitation of the flowchart. A set of two or more
connectors is used to represent the junction of several flow I ines
with one flowline, or the junction of one flowline with one of
several alternate flowlines.

Terminal Interrupt Symbol - Represents a terminal point in a
flowchart, for example, start, stop, halt, delay, or interrupt.

__)

(
3.

Para I lel Mode Symbol
Represents the beginning Oi end of
two or more simultaneous operations.

B-5

GLOSSARY

ANSCii

COS 300 Glossary of Standard Terminology

access time

alphanumeric

The time interval between the instant at
which data is called from storage, and
the instant delivery begins.
A character set that contains letters,
digits, and other characters such as
punctuation marks. The alphanumeric
character set includes the upper case
letters A-Z, the digits 0-9, and most of
the special characters on the terminal
keyboard. Two of these characters,
back slash \ and back arrow ~, are
illegal in user data fields.

American Nationai Standard Code for
r
••
1nrorrnH1on
mrercnange. 1 ms 1s one
method of coding alphanumeric characters.
I

•

assignment statement

See Equa Is statement.

auxi Iiary operation

An offline operation performed by equipment not under control of the central
processing unit.

batch processing

The technique of automatically executing
a gioup of piograms such that each is
completed before the next is started.
The DO command stores groups of
commands, al lowing 11 unattended 11
system operation.

benchmark

A problem used to evaluate the performance of hardware or software or both.

algorithm

A prescribed set of welt-defined rules
or processes for the solution of a problem.
bidirectional f!ow

analysis

The methodical investigation of a problem,
and the separation of the problem into
smaller relocated units for further detailed study.

!n flowcharting; flow that can be extended over the same flow I ine in either
direction.

binary program

The form of user's program which is output by the compiler.

An added descriptive comment or explanatory note.

bit

A binary digit.

blank

- A part of a medium in which no char-

annotation

array

A DIBOL technique for specifying more
than one field of the same length and
type. 503 reserves space for five dee ima I
fieids, each to be three digits iong.
2Al 0 describes two alphanumeric fields,
each to be ten characters long.

GLOSSARY - l

acters are recorded.
bootstrap

A short routine automatically loaded at
system startup time (bootstrap switch) to
read in system software.

code

Means many things to many programmers.
{l) The representation of information,
as in ASCII code. (2) A set of instructions or statements called "a piece of
code. 11 {3) To code means to write a
program.

collating sequence

An ordering assigned to a group of records
based on a key item or field within the
records. One possible ascending sequence
is A-Z, 0-9. Then the descending
sequence is 9-0, Z-A.

command

An operator request for Monitor services;
usually to be executed immediately.

command string

- The characters that make up a complete
command.

A character television display unit of the
operator's console.

communication link

A unit of a computer that includes the
circuits control! ing the interpretation
and execution of instructions.

The physical means of connecting one
location to another for the purpose of
transmitting and receiving information.

COMP

The DIBOL compiler program which
translates from source programs written
in DIBO L language to binary programs
which run on the computer.

comments

Notes for people to read, ignored by
the compiler. Optional, following a
semicolon on any statement Iine.

connector

A means of representing on a flowchart
a break in a line of flow.

branch

A program stream operation including
switching where a selection is made between two or more possible courses of
action, depending upon some related
fact or condition.

buffer

A temporary storage area usually used for
input or output data transfers.

bug

- A program error, or a hardware malfunction.

CALL

Cathode-Ray Tube
(CRT) Display

central processing unit

A program statement that transfers control
to a specified subroutine. The subroutine
must terminate with a RETURN statement,
which returns control to the statement
following CALL statement.

character

A letter, digit, or other symbol used to
control or to represent data. See
Swi tc..h character.

character string

A Iinear sequence of characters.

clear

Setting an alphanumeric field to space
characters, or a decimal field to zeros.
In the Data Definition section of a DIBOL
program 'C' initially clears a RECORD
storage area •

GLOSSARY - 2

A representation of infoimation in a
manner suitable for communication,
interpretation, or processing by either
people or machines. In COS 300
systems, data is represented by characters.

data

data base

data definition

data entry

The entire set of data files avai Iable for
processing by COS 300 data management
system.
The specification of record formats in
both format programs and source programs;
Gives the length of each field, states
whether it is alphanumeric or decimal,
and may give a field name and initial
entry. Data definitions are stored on
the systems device, and may be referenced
by any other COS 300 program.
The process of collecting and inputting
data into the computer data files e Keyboarding is either key-to-tape or key-todisk. The systems uti I ity program,
BUI LO, checks the incoming data for
type and length, and writes the records
on DECtape or disk. The operator can
then print the new data on the I ine
printer to validate the entries.

data independence

- When data files can be accessed by any
program by referencing a separately
stored data definition, data is considered
to be independent.

data language

The DIBO L procedural programming language. Source programs written in this
language are compiled by COMP, producing binary programs which are executed
with the Run-Time system.

GLOSSARY - 3

The planning, development, and operation of a computer system to mechanize
its information flows, and make available
the data needed by the user.

data management

debug

To detect, locate, and remove errors or
malfunctions from a program or machine.

DEC

Acronym for Digital Equipment
Corporation e

decision

- A determination of a future action.

decision table

DECtape reel

A table of al I contingencies that are to
be considered in the description of a
problem, together with the actions to be
token e Decision tables are sometimes
used instead of flowcharts for problem
description and documentation.
Each 4-inch reel contains 260 feet of

3/4-inch wide magnetic tape. Each
reel is a logical file of up to 737 blocks
of 512 characters each. A large file
may consist of up to 63 reels.
detail file

Same as transaction file.

device independence

COS 300 system design permits data files
and programs fo be stored on either
DECtape or disk. At run-time, the
operator chooses the most suitable, or
cvcitob!e, input and output devices.
PIP commands transfer files from one
standard device to another.

device names

3-character abbreviations are used to name
the 1/0 devices.
DTO-DT7
RKO-RK3

TTY
KBD
RDR
PTP
CDR
LPT
DIBOL

direct access

DECtapes 0-7
RK5 disk drives
Terminal printer
Terminal keyboard
Paper tape reader
Paper tape punch
Card Reader
Line Printer

Dlgital's Business Oriented Language is a
higher level progr~ming la-;;guage. It
is an integral part of the DEC DAT ASYSTEM
Series 300 Commercial Operating System.
The process of obtaining data from, or
placing data into, a storage device where
the time required for each access is independent of the location of the data most
recently obtained or places in storage.

EDP

Electronic Data Processing.

END

May be used to terminate DIBOL source
programs. Not required by compiler.

end of tape mark

Control characters which mark the
physical end of a DECtape reel. When
an input file is being read, Monitor
detects this EQT mark, and types a
message for the operator asking that the
next reel in this file be mounted. If an
output file, the Monitor asks for another
reel.

end of file marl<

Identifies the end of the logical file.

equals statement

Manipulates data fields in source programs.
Moves data from one field to another,
clears fields, calculates the value of
arithmetic expressions, and formats data.

error message

- An indication that an error has been
detected.