Digital PDFs

DIGITAL-7-93-U

December 1965

10 pages

Original

0.5MB

Document:	DECTRIEVE-7
Order Number:	DIGITAL-7-93-U
Revision:
Pages:	10
Original Filename:	http://bitsavers.org/pdf/dec/pdp7/DIGITAL-7-93-U_DECTRIEVE-7_Dec65.pdf

OCR Text

IDENTIFICATION

1.1

Digital-7-93-U

1.2

DECtape Retrieval System (DECTRIEVE-7)

1.3

December 17, 1965

PDP

LIB RARY

Digital-7-93-U
Page 1

ABSTRACT

The DECtape Retrieval System for the PDP-7 (DECTRIEVE-7) consists of a self-loading group
of'binary programs which include all of the subroutines necessary to operate the retrieval system itself plus
PDP-7 systems programs or user programs desired for a particular installation. DECTRIEVE-7 allows quick
access to a large I ibrary of programs on DEC tape , perm its easy modification of the system itself, and, except during the creation of the system, eliminates the necessity of handling paper tape for most operations.
The user rece ives the nec~ssary programs for creation of a basic system tape plus a standard
system tape containing many of the most used programs. The user can add or delete any programs in binary
format.
For ease in access to the system a bootstrap program normally resides in memory and will not
be destroyed except in rare instances. In those cases where the bootstrap is destroyed, a small paper-tape
bootstrap is provided which can be loaded with the normal Read-In Mode Loader.
DECTRIEVE-7 is designed mainly for the retrieval of tested programs in binary format and is
not designed to allow compil ing, assembl ing, editing, etc., to or from DECtape. In addition, it is not
compatible with the DECtape FORTRAN System (DECSVS).

REQUIREMENTS

3. 1

Storage

The program requires an 8K PDP-7. DECTRIEVE-7 occupies locations 12600 - 15777, all of
which can be used by a running pro~ram but cannot be overlaid during the loading of a program. The system bootstrap occupies locations' 17500 - 17572 which should not be destroyed during the loading or running of any program.
3.2

Subprograms and/or Subroutines

The basic system uses the PDP-7 DECtape Subroutines and a sl ightly modified version of the
Teletype Output Package, both of which are included as part of the system.
3.3

Equipment

The system requires an 8K PDP-7, with at least one DECtape drive, Teletype, and papertape reader. If any "copy" functions are to be used, a second DECtape drive is required. The basic system tape must always be mounted on a DECtape drive dialed to unit 1.

USAGE

DECTRIEVE-7 includes a variety of functions. For purposes of clarity, the use of the various
functions is discussed in detail in paragraph 6, DESCRIPTION.

RESTRICTIONS
None except tho~e shown under paragraph 3, REQUIREMENTS.

DESCRIPTION

The following paragraphs describe in detail the use of the various system functions. Paragraphs 6. 1. 1 and 6. 1 .2 describe the procedures necessary to create a basic system tape from scratch, and
are not used unless some modification is necessary to the system itself or it is necessary to create a new
binary paper tape of DECTRIEVE-7.

DiS ita 1-7-93-U
Page 2
6. 1

Discussion

6. 1 . 1

Creating a Binary Paper Tape for the System Tape Creation

A series of twelve individual ASCII symbolic paper tapes are provided which should be
assembled as separate programs (except where noted) to provide one, long, continuous binary output.
The tapes must be assembled in the order shown using the standard PDP-7 Assembler, and to reduce the
size of the binary output it is suggested that DDT symbols not be punched.
6.1.1.1

Assemble the tapes in the following order as separate programs creating a single output tape:
Tape 1 - Dummy Directory
Tape 2 - Selective Copy Routine
Tape 3 - Update Routine
Tape 4 - Print Routine
Tape 5 - Copy Routine
Tape 6 - Delete Routine
Tape 7 - Clear Routine
Tapes 8, 9, 10 (as one program) - Memory Portion, DECtape Routines, Teletype Routines
Tape 11 - Bootstrap Routine
Tape 12 - System Creation Routine

6. 1. 1.2
When used, the binary output tape should be loaded so that the System Creation Routine is
the fi rst one read.
6.1.2

Creating a DECtape System Tape

6.1.2.1

Place a certified DECtape on a drive dialed to unit 1, and enable writing.

6.1.2.2

Place the paper-tape binary version of the system in the paper-tape reader.

6.1.2.3

Set the ADDRESS Switches to 17770 and press START.

The tape will be read in, loading itself onto the DEC tape. When complete, the system types
"FUNCTION OR PROGRAM" and waits for the user to request a program. At this point, the entire system
has been created and the DECTRIEYE-7 is ready for use. Any of the six basic functions described below
can now be used.
6.1.3

Printing the Directory

6. 1.3. 1
return •

When the computer types "FUNCTION OR PROGRAM," type in PNT followed by a carriage

6.1.3.2
DECTRIEYE-7 types the names of all files in its directory together with the DECtape block
(in octal) on which they begin. The first six entries always indicate the basic DECTRIEYE-7 programs.
6.1.3.3
When the directory has been listed, the system types "END" and returns to the common wait
loop after typing "FUNCTION OR PROGRAM. II

6. 1.4

Clearing the Directory

6. 1.4. 1

When the computer types "FUNCTION OR PROGRAM," type in CLD followed by a carriage

return •
6.1.4.2
The directory is cleared and rewritten on the system tape.
the six basic DECTRIEYE-7 programs are cleared.

Note that all file names except

6. 1.4.3
After the directory has been rewritten, the system types "END" and returns to the common
wait loop after typing IIFUNCTION OR PROGRAM. II

Digital-7-93-U
Page 3
6.1.5

Deleting a File From the Directory

6.1.5. 1
return •

When the computer types "FUNCTION OR PROGRAM, II type in DEL followed by a carriage

6.1.5.2
The computer types IIFILE TO DELETE. II Type in the correct name of the file tobe,deleted
followed by a carriage return.
6.1.5.3
If a correct name has been typed, the file is deleted from the directory, and the computer
retypes IIFILE TO DELETE." If additional files are to be deleted, type in the next file name and continue
as in paragraph 6.1.5.2; otherwise type a single carriage return.
6. 1.5.4
If a single carriage return is typed, DECTRIEVE-7 rewrites the new directory on the system
tape, types IIEND," and returns to the common wait loop after typing IIFUNCTION OR PROGRAM. II
6. 1.5.5
If the file name typed by the user is a nonexistent name or one of the names of a basic
DECTRIEVE-7 program routine, the computer types "NO" and requests a correct name. Type in the correct
name and continue as in paragraph 6.1.5.2.
6.1.5.6
If an incorrect key is typed inadvertently, press the RUB OUT key. The computer types
"NO," after which type in the correct name and continue as in paragraph 6. 1.5.2.
6.1.5.7
Note that though deletion of a file creates available space in the system tape directory, it
does not make ava ilable the DECtape blocks occupied by the de leted fi Ie. The latter can only be recovered
by copying the system tape (see paragraph 6.1.6).
6.1.6

Copying the Entire System Tape

6. 1.6. 1
In addition to the basic system tape mounted on unit number 1, mount a second certified
DECtape on a drive dialed to unit 2. This second tape wi II contain the condensed system copied from the
original tape. Writi~g must be enabled on unit 2.
6.1.6.2
return •

When the computer types "FUNCTION OR PROGRAM," type Cpy followed by a carriage

6.1.6.3
The routine copies the contents of the original system tape {including all of the basic
DECTRIEVE-7 programs} in the order indicated by the original directory, placing the files in consecutive
blocks on the new tape. This procedure makes available on the new tape all of the DECtape blocks used
by files which have been deleted.
6. 1.6.4
After the entire tape has been copied, the routine writes a revised directory on the new tape,
reestablishes the bootstrap program in memory (which may have been destroyed by the copying process),
types "END," and returns to the common wait loop after typing IIFUNCTION OR PROGRAM. II
6. 1.6.5
Note that though the information contained on both tapes is the same, the blocks occupied
by the various fi les may be entirely different.
6. 1.6.6
To use the newly created system tape, dial out the current DECtape, dial the new tape to
unit 1, place the tape in write lock status, and START at location 17500 (the bootstrap location). (See
paragraph 6. 1 .9.)
The user cannot use the new tape without returning to the bootstrap since the directory
currently in memory refers to the old and not the new tape.
6.1.7

Selectively Copying the Systems Tape

6. 1.7. 1
In addition to the basic system tape mounted on unit number 1, mount a second certified
DECtape (which may be an unused tape or a previously created system tape) on a drive dialed to unit 2.
The routine either copies a particular file onto a previously created system tape or creates a new system
tape with the specific files desired. Writing must be enabled on unit 2.

Digital-7-93-U
Page 4
6.1.7.2
return .

When the computer types "FUNCTION OR PROGRAM," type SCP followed by a carriage

6.1.7.3
When the computer types "NEW TAPE, II type YES followed by a carriage return if a new
system tape is to be created. If the tape on unit 2 is a previously created system tape, simply type a
carriage return. If YES is typed the routine creates a new directory and transfers a II of the basic DECTRIEVE-7 programs and bootstrap. If a single carriage return is typed, the routine reads in the second
directory.
6.1.7.4
When the computer types IIFILE NAME," type the name of the file to be copied followed
by a carriage return. The routine copies the desired file onto the new tape and enters its name in the
first free space in the second directory.
6.1.7.5
When the file has been copied, the computer types "FILE NAME" again. If additional files
are to be copied, continue as in paragraph 6.1.7.4 above. If there are no more files to copy, type a
carriage return. The routine writes out the second directory, reestabl ishes the bootstrap program in memory ,(which may have been destroyed by the copying process), types "ENDII and returns to the common wait
loop after typing "FUNCTION OR PROGRAM. II To use the second system tape follow the directions
outlined in paragraph 6.1.6.6 (q.v.).
6. 1.7.6
If an incorrect key is typed inadvertently, press the RUB OUT key. The computer will type
"NO, II after which type in the correct :mormation and continue.
6.1.7.7
If the second directory is full (4210 entries), the computer types IIDIRECTORY FULL II and
exits from the routine as described in paragraph 6. 1.7.5 above.
6.1.7.8
If the name of the file to be copied already exists in the second directory, the computer
types "PRESS CONTINUE TO DELETE PREVIOUS FILE. II If the file name is correct and the old file is to
be effectively deleted, press CONTINUE. If the file name is incorrect or the old file is not to be deleted,
START at 14777 and a new "FILE NAMP' will berequested. Nevercopyanyofthe six basic DECTRIEVE-7
programs (CLD, DEL, PNT, CPY, SCP,orUPD}.
6.1.8

Adding to the System Tape

6.1.8.1
The system tape to be added to will be the one currently in use on unit 1. Writing must be
enabled. The routine adds binary versions of programs or data to the system tape either from core memory
or from paper tape. Since files can be added from core memory, it provides a handy means of dumping
an entire program or data for future use.
6.1.8.2
return •

When the computer types "FUNCT ION OR PROGRAM, II type UPD followed by a carriage

6. 1.8.3
When the computer types "FILE NAME, II type the name to be given to the file followed by
a carriage return. Only the first six characters typed are used; all other characters are ignored. Any
characters having ASCII codes between 240 and 377 can be used in the name; however the name cannot
begin with either three spaces (which would appear as an unused entry in the directory) or with three left
arrows (which would appear as a deleted entry in the directory).
If the file name typed already appears in the directory the computer types "PRESS CONTINUE
TO DELETE PREVIOUS FILE." If the file name typed is correct and the previous file of the same name is
to be deleted, press CONTINUE. If a different name is desired, START at 14500 and type the correct
name when requested. In no case should a file be added with the same name as one of the six DECTRIEVE-7
programs (CLD, DEL, PNT, CPY, SCP, or UPD).

Digital-7-93-U
Page 5
If no room remains in the directory, the computer types "DIRECTORY FULL, II rewrites the
directory if necessary, reestablishes the bootstrap, types "END," and returns to the common wait loop
after typing "FUNCTION OR PROGRAM." No additional files can be added until one or more files are
deleted.
6. 1 .8.4
When the computer types "FIRST CORE ADDRESS, " type the lowest core location used by
the program or data on loading, followed by a carriage return. Th~ address may not be in the range 0-20
or 12600 - 15777, but may be any other address in normal or extended memories.
6.1.8.5
When the computer types "LAST CORE ADDRESS, II type the highest core location used by
the program or data on loading followed by a carriage return. The address may not be in the range 0-20
or 12600 - 15777, but may be any other address in normal or extended memories. In addition, the program itself may start below 12600 and end above 15777 if that area itself is not required when loading
the program. (The area may be used by the running program.) For example, all of the following pairs of
first and last addresses are acceptable:
21
- 10000
10000 - 13357
21
- 12577
16000 - 17777
16000 - 35777
21
- 17777
12577 - 17777
In the last two cases, the fi Ie would actually be written as two separate records: the first
section ending at location 12577 and the second section beginning at 16000. The user need not concern
himself with this fact however, as both parts are read automatically whenever the file name is referenced.
Note that only one specification of range del imits the entire area used by the program or
data.
6.1.8.6
When the computer types IISTARTING CORE ADDRESS, II type the location at which the
program is to start running when loaded, followed by a carriage return. Here again, the address may not
be in the range 0 - 20 or 12600 - 15777 but may be any other address in normal or extended memory and
need not necessarily be within the program area defined. If the program is not designed to start automatically, the address given should be the address of a HLT instruction within the program. If a second program must be read in, the address given might be 17500, the start of the system bootstrap. If the program
normally would have set up registers below location 21 on loading, the starting address given should
reference some free area in memory where instructions are placed to set up the required registers by programming.
6.1.8.7
After accepting the starting address, the computer types "MEM or TPE. II Type MEM followed
by a carriage return if the information is already in core memory; otherwise type a carriage return to read
in any Assembler-produced binary paper tape. The information should be assembled so that the last tape
ends with a "START 14777" statement. If the program is assembled without such a statement, follow the
directions in paragraph 6.1.8.8 below, after the tape has been read.
6.1.8.8
After the above operation the routine adds the file to the system tape (if already in memory)
or reads in the binary paper tape and adds the program to the system tape. If the information being read
did not end with a START 14777 instruction, the computer either halts or begins executing the program.
To continue the loading process, stop the computer and START at 14776.

Digital-7-93-U
Page 6
6.1.8.9
When the file has been added to the system tape, an appropriate entry is made in the
directory and the routine requests the next "FILE NAME. II If additional files are to be added, repeat the
steps beginning with paragraph 6. 1.8.3. If no more files are to be added, type a carriage return. The
routine writes the updated directory, reestablishes the bootstrap, types "END," and returns to the common
wait loop after typing "FUNCTION OR PROGRAM. II
6.1.8.10
If an incorrect key is typed inadvertently, press the RUB OUT key. The computer types
"NO" after which type in the correct information and continue. If any of the addresses typed fall within
the prohibited ranges, the computer types" NO" and waits for the correct information to be typed.
6. 1 .9

Recall ing DECTRIEVE-7 with the Memory Bootstrap

6.1.9.1
If the bootstrap in memory between locations 17500 and 17572 has not been destroyed, START
at 17500 with the system tape mounted on unit number 1 •
6. 1 .9.2
The routine rewinds the system tape, reads in the memory portion of DECTRIEVE-7 and the
directory, and requests a "FUNCTION OR PROGRAM. II Type the name of the file desired followed by
a carriage return.
6.1.10

Recall ing DECTRIEVE-7 with the Paper Tape Bootstrap

6.1. 10. 1
If the memory bootstrap has been destroyed, place the binary paper tape version of the bootstrap in the reader, set the ADDRESS switches to 17770, and press START.
6.1.10.2
The paper tape is read and DECTRIEVE-7 is recalled from the system tape as described in
paragraph 6. 1 .9.2 above.
6.1.10.3
Note that certain programs (for example, the Assembler) always destroy the bootstrap in
memory because of the areas reserved for symbol tables, etc.

METHODS

7. 1

Discussion

7.1 • 1
DECTRIEVE-7 is designed mainly to facilitate use of the computer during both testing and
production runs of a program. It allows faster recall of data or programs used most often and el iminates
the need for much of the paper-tape handl ing. It does not in itself provide a means of assembl ing, compiling, editing, etc., to or from DECtape but provides merely a handy, fairly efficient, storage medium.
In addition, DECTRIEVE-7 is incompatible with the paper tape and DECtape FORTRAN systems (DECSYS)
and with DDT because of space I imitations. If DDT is used manually (i. e., using the normal paper tape
procedure) DECTRIEVE-7 must be reentered beginning with the paper tape bootstrap.
7.1.2

DECTRIEVE-7 contains three major parts as described below:
1. The bootstrap - Allows quick automatic recall of the Retrieval System.
2. The Memory Portion - Consists of the basic control functions, the Teletype
input and output subroutines, the DECtape subroutines, and a constant dispatch
table to allow the six basic DECTRIEVE-7 programs to communicate with the
subroutines in memory. The directory can also be considered as part of the
memory portion since it is kept in memory whenever the DECTRIEVE-7 is
called.
3. The six basic programs which allow user manipulation of the system itself.

Digital-7-93-U
Page 7
7.1.3
In essence, the memory portion monitors the Teletype keyboard, transfers data to and from
DECtape, and types control messages. If a file is requested, the name is found in the directory, the
correct block or blocks are read, and a transfer is made to the starting address of the program. In the
case of the six DECTRIEVE-7 programs, all are read into the same memory area and communicate through
the dispatch table with the various subroutines in memory.
7.2

Algorithms (Not Appl icable)

7.3

Accuracy (Not Appl icable)

7.4

Error Table

Other than the halt instructions which occur in conjunction with the control messages described previously, only the following halts exist:
Memory Location

Meaning

Procedure

13255

Repetitive DEC tape error. Message
indicates type of error as follows:
100: III ega I format
200: Block not found
300: Error flag during searching;
not end of tape
400: Error flag during reading
500: Sum check error reading
600: Error flag during writing
700: Block mark error during writing

Error has occ'orred three times.
Press CONTI NUE to try three
additional times. If error is
persistent use a new DEC tape •

13306

Interrupt occurred from a device
other than DECtape or Teletype.
Accumulator indicates result of
laRS command.

Clear the offending device flag
and continue if possible. If the
program will not continue, be
sure .the device is cleared and
transfer to the bootstrap at
17500 to start over.

FORMAT

8. 1

Input Format

The only input required by DECTRIEVE-7 is that required when adding to the system tape.
In this case the tape must be an Assembler produced binary tape with or without DDT symbols. The tape
is read with the normal RIM Loader at 17762-17776 in memory. This RIM Loader should never be destroyed.

Di 9ito 1-7-9 3-U
Page 8
8 .2

Core Format
The following table indicates the areas used by DECTRIEVE-7:

Comments

Use

Area
12600-1477

Housekeeping, keyboard monitor,
DECtape, Teletype, and error
routines.

Can be destroyed by any running program, but cannot be destroyed during
the loading of that program.

14500- 14777

Used as the common readin area for
the six basic DECTRIEVE-7 programs.

Same. as above.

15000-15377

System tape directory area.

Same as above.

15400-15777

Directory area for second tape
during copy functions. Also used
by System Creation subroutine.

Same as above.

17500-17572

Permanent DECTRIEVE-7 bootstrap
routine.

Shou ld not be destroyed during the
loading or running of any program, but
can eosi ly be restored with the paper
tape bootstrap prov ided .

17762-17776

Normal RIM Loader

Shou ld never be destroyed.

8 .3

Ou tpu t Format

8.3.1
The organization of the basic DECTRIEVE-7 system tape is as follows: (Block numbers indicated in octal.)
Block 0:
Block 1-4:
Block 5:
Block 6:
Block 7:
Block 10:
Block 11:
Block 12:
Block 13:
Block 14:
Blocks 15 - 1100:
Block 1101:

Not used
Memory portion of system
Directory
Bootstrap
Clear Directory Routine (CLD)
Delete Routine (DEL)
Copy Routine (CPY)
Print Directory Routine (PNT)
Update Routine (UPD)
Selective Copy Routine (SCP)
Any additional fi les added
Not used

Digital-7-93-U
Page 9
8.3.2

The format of the directory is as follows:
Register 0:
~egister 1:
Register 2:
Register 3:
Register 4:
Register 5:
Register 6:
Registers 7 - 252:
Registers 253 - 255:

Next free block
Name of fi Ie (first three letters)*
Name of fi Ie {last three letters}
Starting DECtape block number
One file entry
First core location
Last core location
Starting address of the program
Space for 41
additional entries repeating registers 1 - 6
10
Not used

EXECUTION TIME (Not Applicable)

10.

PROGRAM

10 • 1

Core Map
See paragraph 8.2

10.2

Dimension List (None)

10 .3

Parameter Li st
See complete listing of DECTRIEVE-7 provided in DigitaI-7-93L-U.

10.4

Program Listing
See Digital-7-93L-U for a complete listing of the program and symbol tables.

11 •

DIAGRAMS (None)

12.

REFERENCES (None)

*If the first register of an entry is equal to 777777, a deleted file is indicated and additional entries may
follow. If the register is equal to 000000, the end of the used portion of the directory has been reached
and no further entries follow.