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Document:	PDP-11 Variations on a Theme
Order Number:	XX-93B67-60
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Pages:	50
Original Filename:	dec.pdp-11.1977.102646131.pdf

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PDP-11 Variations on a T h a e

This uniquely successful computer family is based
around a compatible set of processors -ranging
from single-board microcomputers to full multipurpose computer systems. All of these processors
are built upon a common architecture that uses a
similar instruction set and input/output system.
This common architecture means you can expand
a PDP- 11 system when your workload grows, since
nearly all of our peripherals and software will work
with any PDP- 11 processor. It also means you can
have a mix of PDP- 11 systems doing different
things and they will be able to communicate among
themselves. A single development and documentation effort will support them all. But most of all,
this commonality means you can start today with
the PDP-11 system you want, knowing it can grow
with you in any direction to meet tomorrow's needs.
A key factor in the PDP- 11family's success is that
all system elements -processor, memory, peripherals-plug into a UNIBUSm,a single, high-speed,
data path.
The UNIBUS prevents any PDP- 11 system from becoming obsolete. Its asynchronous design allows
the processor, memory and peripherals to operate
at their own speeds. Thus, larger or faster peripherals or memory can replace older versions without
affecting the system. And since there is a compatible UNIBUS on all but the smallest PDP- 11
system, you can freely exchange peripheral devices
from system to system.
The UNIBUS has performance advantages as well.
It gives fast devices direct memory access without

the need for multiplexers or synchronizing hardware. Memory and peripherals can send, receive, or
exchange data without processor intervention and
without intermediate buffering in memory. Thus,
a n I/O device can be communicating with memory
at the same time the processor is performing
computations.
Direct communication over the UNIBUS means the
PDP-11 does not require separate I/O instructions.
The same instruction that performs a register-toregister transfer within the central processor can
perform a memory to I/O device transfer, a n I/O
device to memory transfer, or a transfer between
two I/O devices.

Software Compatibility
Since all PDP- 11 processors use the same basic instruction set, programs developed on one PDP- 11
are immediately usable on larger models and, by
using the proper coding conventions, on smaller
models as well. Common software means no conversion problems when you move to alarger PDP- 11
system. Programs developed on one PDP-11 will
run on other systems under the same operating
software, regardless of the specific processor.

Programming Flexibility
The comprehensive PDP- 11 instruction set and
addressing modes yield over 400 commands, providing the programming flexibility of a large computer in a 16-bit mainframe. The set offers a wide
choice of commands, so that a single instruction
frequently suffices where several would be required

Digital's leadership of the minicomputer revolution
remains unchallenged. Not only has the PDP- 11
family redirected the path of computer technology,
it has become the world's most popular minicomputer series in doing so.
Behind this success are 20 years of technological
accomplishment. Digital's small computers moved
computing power beyond the data processing
centers of large organizations for the first time.
Today our PDP-1 1s stand at the forefront of the
shift to distributed processing.
Digital's PDP- 11s hold a unique position not only
because they are economical and efficient, but because they have the hardware, software, and supporting services to do what computer users want to
do today
Nothing illustrates this better than Digital's commitment to data communications. First we engi-

neer all of our computer systems with data communications in mind. Then we complete the circle
with a full range of communications-oriented
hardware and software.
DECnet, for example, is the set of software tools that
lets our PDP- 1ls, PDP-8s, DECsystem-10s and
DECsystem-20s share peripherals, files, and programs among themselves. What DECnet does is
simplify start-up of almost any sort of network
using Digital computers, whether you plan to link
dedicated microcomputers to a minicomputer, or
set up a large-scale distributed processing network
across a continent.
Digital customers are the beneficiaries of this sort
of technological pioneering. When our engineers
break new ground, they simply widen the scope of
what you and your staff can do with the Digital
products you already have.

The PDP-11 family covers the spectrum of
small to large minicomputers. Yet all PDP-11 s
have much in common. If you're buying more
than one, or if you think your requirements
mightgrow or change, that makes things a lot
easierfor you. It means you don't have to buy
more than you need now.

The UNIBUS,built into all but the smallest
PDP-11 s, guarantees that changing technology won't leave your system behind It
means you can easily attach larger orfaster
peripherals or memory wheneveryou want to.
The UNIBUS also makes programming easier:

All PDP-11 processors, however small or big?
respond to the same set of instructions,soprograms writtenfor one PDP-11 can run on a
larger PDP- 1 1, and vice versa.

And this set of instructions is very large, which
saves programmers' time.

Fully vectored hardware interrupts, eight
general registers, a n dfourpriority levels help
PDP-1 1s work egiciently.

in a traditional computer. Larger PDP-11models
provide a superset of the basic family instruction
set.
The PDP-11family allows bit byte and word
addressing in both single- and double-operand
formats. This helps save memory space and simplifies the implementation of control and communications applications.
The PDP- 11family's use of double-operandinstructions allows programmers to perform several operations with a singie instruction. For example,ADD
AB adds the contents of locationA to locationB and
stores the result i n location B. It might take three
instructions to do the same thing on another
minicomputer.
The PDP- 11instruction set also contains a full set
of conditional branches, eliminating excessive use
of "jump" instructions. A branch is also included
for overflow of a signed integer, eliminating the
need for a separate subroutine.

Hardware Interrupts
The interrupt system for the PDP-11 is another
advance in small computer technology.With fullyvectored interrupts, the system eliminates the
high-overhead software that determines the device
service routine and code necessary to save system
status. The multilevel hardware interrupt system is
a standard PDP-1I feature, not an extra-cost
option.
This system allows interrupts to be enabled or disabled, through software, during program operation. Such masking allows priorities to change
dynamically in response ta system conditions. For
example,areal-time program can disable data entry
terminals whenever critical analog data is being
collected. As soon as the scan is complete, the
terminals are ready for use again.

Eight General Registers
With eight general registers, PDP-11s give the programmer the flexibility of a large-scale computer.

Since these are general purpose registers, the programmer can assign them dynarnicallp depending
on whether the need is to achieve computational
speed, manipulate a pointer, or use the registers for
temporary storage.

Priority Scheduling
PDP-11 computer systems provide four prioriQ
levels, each of which can handle an almost unlimited number of devices. The priority of a device
is a function of the device's physical location on the
UNIBUS- the closer to the processor, the higher its
priority on that level.
PDP-11 architecture directs the device causing the
intenupt(s)to provide a direct vector to its own
service routine, eliminating the slow and tedious
operation of polling all devices to see which one
interrupted.
The device also provides status information for its
own service routine. Thus, the programmer has the
flexibility of assigning a device to a higher priority
and its service routine to a lower priority without
writing special software.

The advantages of the PDP- 11processors are just
a part of the PDP- 11 story however. The broadest
range of operating systems in the computer industry is available for your use. The choice extends
from single-user program development systems to
powerful timesharing, real-time, and multipurpose operating systems.
The selection of industry-standard programming
languages is just as comprehensive.The smallest
PDP- 11s can run several versions of FORTRAN,
BASIC, and APL, while larger systems can also support COBOL and RPG 11. And many of our systems
are available with a range of application software
and utilities.
The high degree of commonality among PDP- 11
programming languages, system programs, and
data management services facilitates migration
from one operating system to anothe~;as well as the
mixing of different operating systems within a
single location or information system.
The range of peripherals is just as thorough.
Whether you need minimal disk storage or enough
capacity for a large on-line data base, Digital can
provide it. If you want terminals for inquiry/
response, data entry, or hardcopy listings, Digital
has them. And there's an equally broad selection of
tape transports, unit record equipment, and special
purpose interfaces.

Digital designs and builds most of this equipment
specifically for use with our own computers.Yet,
we've become such a leading peripherals manufacturer that you'll find them included in more and
more computer systems from other vendors. Our
DECwriters, in fact, are the industry's fastestselling hardcopy terminals.
For PDP-11 users, this all means an exceptionally
wide choice of high-quality peripherals, at exceptionally competitive prices.
But hardware and software are not the sum total of
the PDP-11 family's strengths. Digital backs up its
computer systems with a worldwide field service
organization of over 4,000 people; a software support group dedicated to helping customers with all
their software needs; and training facilities, also
located worldwide, that offer over 100 scheduled
courses.

There is a comprehensive range of operating
systems that direct the processors'power
toward specflc ends.

On top of that, PDP-11 users have an exceptionally wide choice of programming languages, each of which is especially suited to
particular tasks.

Digital has afull line of peripheral equipment to match thejobs you plan ...

...and the supporting services to maintain
your hardware and sofhoare and to train your
people.

PDP- 11s come i n prepackaged systems to
assure the right equipment mixfor yourpurpose. All the right cables, plugs, and power
suppltes are included

Digital further adapts PDP-I 1 systemsfor
particular uses.

T h e PDP-1 l family oseers the Original Equipment Manufacturer a single source of supply,
discount policies, and worldwidefield
service.

How do you match your application plans, your
budget, and your long range goals to a minicomputer system? Digital takes much of the work out
of it for you.
Our PDP- 11 products are available in preconfigured systems. We sell these systems through
marketing groups that specialize in solving problems in particular application areas. That means
your sales representative will be used to dealing
with the general type of application you plan.
Your first step is choosing the PDP- 11 operating
system that fits the type of application you have in
mind. The next step is adding the processor and
system device that your operating system requires.
Then you add additional memory and peripherals
to this basic system, choose a load device, console
device, and hardware and software maintenance
plan.
Digital's marketing groups provide additional
applications-oriented hardware and software options for PDP- 11 systems.Our CommercialProduct
Groups, for example, market the DEC Datasystem
family, which has led the way toward interactive
processing in the commercial environment.
All Datasystems built around PDP-11s provide the
commercially oriented user with Indexed Sequential Access Method (ISAM) file support, and
DECFORM, an easy to use forms creation and data
entry programming language. All of them run the
same source code written in the high-level DIBOL
language, while supporting an increasing number
of concurrent tasks and user terminals.

Original Equipment
Manufacturers (OEMs)
OEMs as well as end users can profit from Digital's
unequaled range of products. Digital is the anly
computer manufacturer that can offer the OEM a
single source of supply for processors, software,
and peripherals.
Digital's discount policies help OEMs offer highquality products at competitive prices. And our
worldwide hardware and software support augments OEM's own servlce organizations,
Whether you are an end user or OEM, the PDP-11
family structure protects your investment.

Nearly 50,000 PDP- 11s have been sold since the
series introduction in 1970. The success of the
PDP- 11 family is not limited to anyone market area
or type of application; the PDP- 11'sadvantages
have been enough to make it pre-eminent across an
enormous number of computing applications.
The range and unique strengths of the PDP-11
operating systems deserve major credit for this.
RSTS/E ushered in a whole new era of economical
timesharing; RT- 11 let dedicated minicomputer
test stands obsolete cumbersome industrial
relays; the RSX family of operating systems made
real-time data collection and process control practical and economical; MUMPS did the same for online data base information systems; IAS let users
perform simultaneous timesharing, real-time, and
batch processing on a single computer.One of these
operating systems was designed with your application in mind.

The Single-User Operating System
RT- 11
RT- 11 is an efficient, single-user, real-time disk
operating system for interactive program development and dedicated on-line applications. There are
over 4,000 RT- 11-based systems in use, making
this the world's most popular real-time operating
system.
The compactness and efficiency of the RT- 11 realtime system allow it to run on the lowest-costhardware configurations, while giving full rein to a
PDP- 11's speed. And RT- 11's simplicity makes it
extremely easy to program.

RT- 11 supports both single job (S/J) and foreground/background (F/B)monitors. The F/B
monitor allows both a foreground and background
program to operate. The foreground handles realtime functions and has priority on systems resources; program development or batch jobs can operate
in the background whenever the foreground is
not busy
RT- 11 includes a variety of system and program
development utilities and offers optional support
for FORTRAN IV,FOCAL, BASIC, APL, and MACRO
assembler.

The Timesharing Operating System
RSTS/E
RSTS/E (ResourceSharing Timesharing System/
Extended) provides efficient timesharing for up to
63 simultaneous users. RSTS/E supports BASICPLUS, an enhanced version of Dartmouth Standard
BASIC, and optionally, BASIC-PLUS-2 RPG 11,
COBOL, FORTRAN IV,and APL.
Each RSTS/E timesharing user can have virtually
the entire system's processing power, utilities, and
peripherals at his command during program
development or execution.
The operating system's multitasking support gives
it the flexibility that timesharing demands. Its
dynamic scheduling algorithm allocates processor time, memory space, file space and peripherals
to continually keep processing efficient.The system
manager can also set priorities to favor specific
jobs. RSTS/E also provides the system manager

Customers have successfully used PDP-1 1s
for everythingfrom running a lathe to running
a business. The PDP-11 operating systems let
the processors excel in each of these dflerent
areas.

One operating system is typically used with
small PDP-11 s set up to do a single task,such
as controlling an industrial test stand in a
factory.

Another is the timesharing operating system
for PDP-11 computers.

Timesharing puts special demands on any
operating system because it callsfor a changing mix of users and protection of everyone's
privacy. Even a relatively small PDP-11 system can provide timesharing service to
numerous users.

Still another operating system is designedfor
a situation where many people want quick
access to a central datcrfile stored in the computeralong with the ability to quickly change
or update that central data base.

with a number of utilities that keep track of system
usage and help in allocating system resources.
The operatingsystem provides all the securitylocks
necessary for a multi-user timesharing environment. Files can be protected from access on an individual, group, or system basis. Files can also be
accessed by many users while being updated online. Total or selective flle backup can be done online without disrupting users or it can be done offline. Other protective measures include on-line
backup/restart, installation-oriented protection
schemes, catalogue-oriented flle identification, and
removable storage media
RSTS/E's conveniences include easy-to-use system
generation features, comprehensive documentation for all levels of users, and standardized and
indexed error messages.
Extensive commercial and data management facilities include ISAM (Indexed Sequential Access
Method), relative access method, decimal arithmetic, and line printer spooling. Sort facilities include a BASIC-PLUS sort package and an optional
standalone multivolume sort package. This gives
the RSTS/E user an integrated set of commercial
applications development tools.

The Multi-User Data Base Management
System
MUMPS- 11
MUMPS-11is a multi-user data base management
system that includes both an operatingsystem and
a high-level language. The MUMPS- 11language
was originally developed in 1968by the Laboratory
for Computer Science at the Massachusetts
General Hospital.
The MUMPS-11language has text-handling capabilities that facilitate the inspection of any piece of
data for content (such as particular keywords) or
for any format (such as letters,numbers or punctuation characters at particular positions in a piece
of text).These capabilities are extremely important

for accepting or rejecting newly entered data, and
for facilitating the on-line correction of data at
entry time. Other text-handling capabilities include the ability to combine several pieces of text
into one, and to divide text into segmentsif desired.
The language's hierarchical file structure allows
users to design data files to suit their own requirements. This is significantbecause the data in most
record systems (for example, medical records,
financial records, and so on) actually do have many
different levels of importance and detail. The
MUMPS-11 user can create file structures that
mimic the logical structure of the data. The
language's hierarchical flle structure also simplifies storage or accessing of any given data item.
The MUMPS-11language's high-level nature Is
suited to the kind of problems the language is used
to solve. MUMPS- 11may be used by programmers
with relativelylittle training.They can produce useful working code from the first daythey start to program, even though full utilization of MUMPS-11's
capabilities requires a substantial amount of
programming experience.
Since MUMPS- 11 is an on-line program development and data storage and retrieval system, a programmer can write, debug or modifl a program to
quickly develop a working application.A user can
enter, inspect or change data interactively and efficiently. Since MUMPS- 11 is implemented as an interpreter, it eliminates the need for any timeconsuming compilation step or extra storagespace
for compiled code in addition to the source code.
Data base management activities usually involve
sensitive information at some point. Therefore,
safeguards must be established to allow access only
to authorized personnel.
Each user of the MUMPS-11 system gains access to
the system's programs using a special login sequence which involves one or two access codes
(depending on the privileges of the user). These

codes, provided by the system manager, are the User
Class Identifier code or UCI, and the Programmer
Access Code or PAC. MUMPS-11 allows up to 16
UCIs (classes of user).
MUMPS-11 also uses a concept called "tied
terminals" as part of its approach to data security.
The system manager can "tie" any terminal to a
given program. Simply striking a key on the tied
terminal will cause it to begin executing its
assigned program. It is then impossiblefor the user
to go through the login procedure.
All PDP-11s can run MUMPS. A single PDP- 11 system can support up to 64 MUMPS terminals.

The Real-Time Operating System
RSX- 11M
RSX- 11M is the primary PDP- 11 real-time operating system. It is ideal for factory automation,
laboratory data acquisition, graphics, power monitoring, and other applications that demand an
immediate response.
RSX- 11M delivers all that these applications
require of an operating system. It supports multitasking, dynamic memory management, multiple
programming languages, interactive program development, and a wide range of equipment
interfaces.
RSX-11M accomplishes multiprogramming by
logically dividing available memory into a number
of named partitions. Tasks execute in a specific
partition, and all partitions in the system can
operate in parallel.
RSX- 11M systems with the memory management
option protect the memory area assigned to a task
from other tasks executing in the system.With
memory management, each task has a specific
address range in which to execute, and can reference and alter memory onlywithin the area it owns.
Very large programs can be executed using either
disk or memory overlay structures.

driven, in contrast to systems which use a static
scheduling mechanism to determine a task's eligibility to execute. The basis of event-driven task
scheduling is the software priority assigned to each
active task When a significant event, (such as I/O
completion) occurs, the executive interrupts the
executing task and searches for the highest priority
task capable of executing.
Once a task is in memory; the executive normally
allows it to run to completion in a multiprogrammed fashion, even if its memory is required for
the execution of a higher priority; non-resident
task. However, if the system manager wants to free
memory for execution of a higher priority task, a
task can be declared checkpointable when created.
A checkpointable task currently active in a partition can be interrupted and swapped out of memory to disk when a higher priority task requests its
partition. Later, after the higher priority task has
finished, the checkpointed task will be restored to
active execution at the point where it was
interrupted.
RSX-11M tasks can be written in MACRO assembly language or optionally in BASIC-PLUS-2,
FORTRAN IV, FORTRAN IV-PLUS, or COBOL.

RSX- 11S
RSX- 11S, a subset of RSX- 1lM, provides a dedicated, execute-only environment for monitoring
and controlling many real-time processes concurrently Program development and RSX- 11 s system
generation takes place on a host RSX- 11M system,
allowing the RSX-11 s system to be wholly dedicated to its real-time task.

The Multifunction Operating System
IAS
IAS, the Interactive Application System, supports
concurrent real-time, timesharing, and batch
processing, making it the ideal multipurpose operating system.Since a n IAS system also offers~ower-

There's also real-time operating softLuarefor
situations where a PDP-11 has to collect,
analyze and respond immediately to information comingfrom a numberof machines
or instruments.

Tasksfor the real time operating system can
be written in a variety of programming
languages.

Our multi-function operating system canperfonn timesharing, real-time tasks and batch
nmcessing at the same time, on one computer:

ful, easy-to-use program development, it is a
natural host for smaller RSX- 11-based systems in
a distributed computing arrangement.
An IAS system can handle data collection and
process control tasks, using data from its own
peripherals and from smaller satellite systems, and
simultaneously produce management reports. At
the same time, the system can offer efficient timesharing service to scientists and engineers.
IAS has all the capabilities to do these many different tasks well. Its extensive system management
facilities equip it for real-time tasks; its comprehensive file protection qualifies it for timesharing;
its unmatched range of programming languages
and utilities make it a general purpose
operating system.
Among M's strengths are a singe command
language that's easy to learn and use; priority
scheduling for real-time tasks; submission ofbatch
jobs from interactive terminals; and timesharing
services for efficient development of interactive '
application programs.
The operating system also provides a simple internal software interface for the development and
use of special-purpose,multi-user interactiveapplications; a sophisticated file system providing
device independence, file protection, sequential
and random file access; dynamic allocation of system resources; use of shared, reentrant code to
minimize memory requirements; system management facilities for system configuration, generation, and control; and facilities to account for and
restrict the use of system resources.
Facilities include a MACRO assembler, a full set of
system and user utilities, data management facilities for manipulation of records, files,and volumes,
system management facilities, extensive user and
system protection, and optionally, FORTRAN IV;
FORTRAN IV-PLUS, BASIC, BASIC-PLUS-2and
COBOL language processors.

Digital's high-level languages let you move freely
among operating systems. These languages span
the breadth of the PDP-11 operating systems, and
conform to the industry standards that exist. In
some cases, more than one version of a particular
language is available on a single operating system,
each optimized to meet particular requirements.
BASIC- 11
BASIC- 11 is an easy-to-learn,conversational
programming language that uses simple English
words, abbreviations, and familiar mathematical
symbols to perform operations. The BASIC instruction set contains powerful yet easy-to-learn
commands that allow novices to quickly become
accomplished applications programmers. With experience, programmers can start using the advanced techniques available in the language to
perform intricate manipulations or to express a
problem efficiently and concisely
Digital's BASIC-1 1 is an immediate response, interactive language compatible with Dartmouth
standard BASIC. It gives the user the capability to
develop and debug a program in a minimum
amount of time. BASIC- 11 can be used for relatively
large data processing tasks as well as quick onetime calculations.
BASIC-11 is available under RT- 11, RSTS/E,
RSX- 11M, and IAS.
BASIC-PLUS
BASIC-PLUS offers many additional functions not
found in standard Dartmouth BASIC or most other
versions of the language.

BASIC-PLUS has a comprehensive group of string
operations that provide efficient processing of
alphabetic data, including names, addresses,
sentences and paragraphs. The BASIC-PLUS user
can append strings or compare them. It's possible
to extract, examine, or search for a string of
characters contained within a larger string.
BASIC-PLUS has an immediate mode of operation
that allows commands to be immediately executed
instead of stored for later execution. BASIC-PLUS
commands can also be more than one line long.
BASIC-PLUS includes a set of 13commands for performing matrix input/output, addition, subtraction, multiplication, inversion, and transposition.
The language also has extensions that provide a
highly efficient means of handling records composed of fixed-length fields.
The language has program control and storage
facilities that can store both programs and data on
any mass storage device and retrieve them for use
during program execution. A PRINT-USING statement provides for tabs, spaces, and column headings, plus precise specifications of output line
formatting and floating dollar sign, asterisk fill,and
comma insertion in numeric output. Listings can
be on a line printer as well as on a terminal.
BASIC-PLUS is included with the RSTS/E
operating system.
BASIC-PLUS-2
BASIC-PLUS-2 is a superset of BASIC-PLUS with
true compilation capability. Therefore BASICPLUS-2 application programs run much faster
$
i&

Digital 's high-level programming languages
put the computer'spower in theprogrammer's
hands. Since these languages conform to industry standards, most programmers are alreadyfamiliar with them.

Each language is a tool that is good forparticular kinds of projects. Whatever your application, there's a PDP-I I programming language to match it

than BASIC-PLUS programs do. BASIC-PLUS-2
files also interface directly to the RMS-11 record
management system, which allows the BASICPLUS-2 user to create files, do record mapping, and
access records sequentially, randomly; or by key.
BASIC-PLUS-2 also provides a CALL statement that
lets it access external subroutines. There are also a
number of statements that allow the programmer
to interactively observe and controlprogram execution. BASIC-PLUS-2 is supported under the
RSTS/E, RSX- 11M and IAS operating systems.
COBOL
PDP-11 COBOL provides terminal-oriented,fast
data processing for commercial applications.
Source programs are written in the American
National Standards Institute (ANS)COBOL-74
language. PDP-11 COBOL is a fully implemented
intermediate level compiler conforming in language element, representation, symbology and
coding format to the ANS specification.In addition,
it includes a number of high-level specifications.
Major features include use of the Digital standard CALL sequences for external subroutines; use
of the RMS- 11 Record Management System; an
ANS standard COBOL segmentation facility; and
ANS standard string and substring manipulation.
COBOL is an optional language processor for
RSTS/E, RSX- 11M, and IAS.

FORTRAN IV
PDP-11 FORTRAN IV is a substantially improved
form of the standard scientific programming language that can be used on any PDP- 11 configuration. New optimizations make programs smalland
fast. Powerful extensions permit markedly easier
program coding.And FORTRAN IV 's compilation
speed minimizes program development time.
Since FORTRAN IV is a superset of ANS standard
FORTRAN, programs written to this standard but
used on other computer systems can run unmodified under FORTRAN J
Y

FORTRAN IV-PLUS
A superset of FOR'PRANIY FORTRAN IV-PLUS supports the same enhancements to the ANS standard,
but also includes numerous extensions. The
primary differences between the FORTRAN IVand
FORTRAN IV-PLUS compilers are that the
FORTRAN IV-PLUS compiler produces highly optimized PDP-11 machine language code; creates
hard code that uses the Floating Point Processor
option in high-end PDP- 11s; and can produce
shareable code.
FORTRAN IV-PLUS conforms to the specifications
for ANS FORTRAN X3.9-1966. It is available under
RSTS/E, RSX-1lM, and LAS.

A P L 11
APL11 uses one of the most concise, consistent,
and powerful character sets ever devised. It is flexible enough to solve problems in text-handling and
commercial data processing as concisely and m
easily as it can solve problems in mathematics and
statistics. It is available under RSTS/E and RT- 11.

RPG I1
RPG I1 is a complete report program generating system that provides users with a ready means of
developing applications programs. It supports
almost all functions offered by industry versions of
RPG 11,and provides significant improvements over
RPG I. It is available under RSTWE.

PDP- 11 SORT
SORT is a fast-workingutilityprogram that lets the
user rearrange, delete, and reformat records in a
mass storage file; select a sorting process and input device that best suit the processing environment; and create new file indices for accessing a
large data base.
SORT also allows the user to batch stream several
sorting jobs and to define specification files for
complex record definitions. The SORT Drograrn

The PDP- 11 family provides a full range of data
management tools. The choice extends from the
operating systems' file control systems to block
input/output support: to sequential and relative
logical file/record support with a multi-key index
sequential option; to a complete, CODASYLstandard data base management system.

Record Management System
RMS- 11, Digital's Record Management System,
allows user-written application programs to create,
access, and maintain data files with efficiency
and economy
RMS-1 1's variety of file organizations and access
modes gives the user the ability to choose the
method best suited to the application. RMS- 11 supports sequential, relative, and indexed files which
users can access sequentially randomly, or by key
The multi-keyed access option provides both
generic and approximate key searches. Records can
be either fixed or variable length.
RMS-11 also includes a set of utility programs for
the creation and maintenance of files, and a set of
operating system routines through which records
are transmitted to and from user programs.
RMS-11 complements DBMS-11,Digital's Data
Base Management System, by providing file and
record handling capabilities for applications whose
size and data structures do not require the complete data base management services of DBMS-1 1.
RMS-11is fully supported with COBQL and BASICPLUS-2 under RSTS/E, RSX- 11M and IAS.

DBMS- 11 Data Base Management System
DBMS- 11 is a CODASYL-standard data base
management system that uses the 'set definition'
as the basic building block with which even the
most complex data relationships can be defined.
DBMS- 11 gives the data base administrator better
overall control of data. It separates data definitions
from data references and allows definition of logical, applications-oriented relationships. Redundant data is eliminated. Data protection is maximized. Program development and maintenance
efforts are reduced. And the data base as a whole
can be treated as a single entity rather than as a
collection of similar but unrelated information
and applications.
DBMS- 11supports multi-level sequential, hierarchical (tree),and network data structures, providing the data base administrator with enough
flexibility to define a data base structure that accurately reflects the installation's needs.
DBMS- 11provides room for growth in several
directions. If the user needs to grow beyond a
DBMS-11 system, the DECSYSTEM-20 and
DECsystem-10 both use CODASYL-standard data
base management systems. This greatly simplifies
the task of program conversion.
DBMS- 11is available under the IAS operating system and is supported by FORTRAN IV-PLUS,
COBOL, BASIC-PLUS-2, and MACRO.

Data management services and utility software packages help you manage and work
with the information in your computer
system Digital provides afull range of this
software,from the most basic to the most
comprehensive.

DECnet isjust one of the software tools that
lets PDP- I 1 s communicate with each other;
with other Digital computers, and with nonDigital computers.

The PDP-11 processor family starts off with a
microcomputer, includes two mid-range minicomputers, and culminates in a powerful 'supermini'.
Not only do these PDP- 11 models increase incrementally in size and power, but each model adds
extra features that are appropriate for the kinds of
applications its power can handle.
PDP- 11/ O 3
The PDP- 11/03 has been made possible through
the use of Large Scale Integration (LSI)technology.
Digital has been able to create a chip set in the
form and function of a standard PDP- 11yet small
enough to be packaged along with 8 K bytes of
memory on a single circuit board. The PDP-11/03
includes the chassis, operator's console, processor,
memory, backpanel with expansion space, power
supply and interface modules.
The PDP- 11/03 features a full PDP-11 instruction
set, vectored interrupts, an asynchronous, bidirectional bus, microcoded debugging facilities, operator interface and bootstrap loader, real-time clock
input, and power-fail/auto restart.

PDP- 11/ O 4
The PDP- 11/04 is a low-cost system for data acquisition, converting analog signals to digital signals,
analyzing pulse heights, storing accumulated data
on magnetic tape, and other dedicated applications. It is the smallest PDP-11 with a UNIBUS.
The PDP-11/04 can have as little as 16K bytes of
memory for straightforward applications, or as

much as 56K bytes for more extensive programs,
which can be written in a high-level language such
as FORTRAN IV or BASIC.
PDP- 11/34
The PDP- 11/34 is a midrange member of the
PDP-11 family As a microprogrammed processor,
the PDP- 11/34 CPU is so compact that the entire
CPU logic is contained on two circuit boards.
There's considerable chassis space for
later expansion.
The PDP- 11/34 incorporates a number of large
processor features which increase its capabilities
beyond those found in other computers in its class.
These features include: integral memory management hardware that provides program protection,
memory relocation and addressing of up to 256K
bytes, and integral extended instruction set (EIS)
that provides hardware fixed-point arithmetic in
double-precisionmode (32-bitoperands).A
floating point processor is optional.
PDP-11/55
The PDP-11/55 is especially designed for fast execution of FORTRAN compiled tasks, whether for
critical process control, laboratory simulation
experiments, engineering and scientific calculations, or other applications of this kind.
Overlapped operations and high-speed components give the 11/55 its high performance. The
processor takes full advantage of such advanced
components as bipolar memory, a high-speed

Digital has been aleader in the trend towards interactive computing and distributed processing. As a
result, we provide a particularly useful range of
communications software.

DECnet
DECnet is the set of software tools that allow
Digital computer systems-PDP-8s, PDP- 11s,
DECsystem-10s and DECSYSTEM-20s-to communicate programs and data among themselves.
DECnet allows different Digital computers within
a network to control and use remote peripherals as
if they were local, to access remote files, and to send
programs to another system for loading and execution. In other words, DECnet provides device sharing, file sharing, and program sharing.
This means DECnet lets you store information on
one computer system, then down-line load it to
other computer systems in your networkwhen they
request it. Similarly DECnet's support for downline system commands lets programs in one computer system send directives to other computer
systems within a network.
One result of these features is that you can develop
programs on a sophisticated host computer and
then down-line load them to small, execute-only
computers elsewhere in your network. Finally,
DECnet's independence from line characteristics
lets you include both full- or half-duplex lines, and
serial or parallel transmission within your network.

DICAM
DICAM (Datasystem Interactive Communications
Access Method) is a software package that lets our
PDP- 11-based DEC Datasystems communicate
interactivelywith application programs on an IBN
360/370 host. DICAM does this by providing a
communications path that makes the Datasystem
communicate like an IBM 327 1remote display controller on an IBM system. That means an IBM host
can support a Datasystem a s easily as a standard
host option, leaving you free to take advantage of
the full range of 360/370 access methods, operating systems, and system management packages.

Remote J o b Entry Packages
Digital has an assortment of remotejob entrypackages for non-Digital mainframes. An IBM 2780
emulator, an IBM HASP emulator, a Control Data
Corporation UT200 emulator,and aSpeny UNIVAC
1004 emulator are all available.

The PDP-11 processorfamily starts oflwith a
microcomputer;goes up through mediumscale minicomputers and culminates in a
poweflul "supemini.
"

Each larger PDP-I 1 model adds extrafeatures that complement its increased
pel3fonnance.

(5.43microsecond 64-bit double precision multiply) double precision floating point processor, and
hardware memory management.
Overlapping occurs on several levels: instruction
pipelining,where the next program instruction is
fetched while the current one executes;CPU
independent floating point calculation; and a bus
structure that allows direct memory access without cycle stealing on the UNIBUS.

PDP- 11/6O
The PDP-11/60 is a midrange system that offers
performance and reliability features usually found
only in larger, more expensive systems. The 11/60
provides a cache memory system; abuilt-in floating
point unit; an optional high speed floating point
accelerator for fast execution speed in heavily
computational applications; and an optional
writeable control store (WCS) for special-purpose
microprogramming.
This combination of features makes the 11/60
ideal for midrange, real-time applications including scientific and industrial data acquisition
and control, problem solving in engineering departments, simulation, medical processing, and
data communications, text composition, graphics,
and transaction processing and management
information systems.
The 11/60 brings more than power and economy
to these applications. Parity checks on cache and
core memory, error correction on MOS, and aWCS
parity check add extra reliability.
Packaging enhancements such as extra cooling
capability, built-in cable troughs, grounded cabinet
panels, swing out card cages, and a shock-absorbing suspension add to the 11/60's reliability and
ease of maintenance. An innovative operator's
front console, a hardware diagnostic bootstrap
loader, and a diagnostic control store module cut
trouble shooting time.

PDP- 11/70
The PDP-11/70 provides the highest throughput
of any PDP- 11 system. Its performance can be
applied to applications involving many concurrent processes, or to a demanding single process.
For example the 11/70 is ideally suited for a college computer center where it can simultaneously
handle laboratorydata acquisition, interactive
student programming, and administrative batch
processing. In its smaller configurations,the 11/70
is appropriate for very demanding single-function
applications such as timesharing or dedicated
real-time applications.
The unique feature of this computer is the
throughput you get for the price. This means fast
instruction processing, fast memory (an integral
cache memory system yields an effective memory
cycle time of less than 400 nanoseconds,while
main memory is ECC MOS or parity core),fast
32-bit I/O paths that complement the UNIBUS,
and high-speed mass storage devices.
The PDP-11/70 is compatiblewith the full line of
PDP-11s and includes all the features that have
made the PDP-11 family the world's fastest selling
small computer family

PDP-11 peripherals range from paper tape readers
to high speed disk packs, from small auxiliary
printers to full graphics subsystems, from A/D
converters to heavy duty industrial controllers.

Disk Drives
Digital's disk family is comprehensive enough to
provide appropriate on-line storage for the broad
range of PDP-1 1 systems and their applications.
The current disk product line consists of the RXO1
floppy disk for small systems, the RK05J/RK05F
and the RK06 cartridge disks for small to mediumsized PDP- 11 systems, and the W04/RP05/W06
disk pack drives for large systems. The RS03/RS04
head per track disk drives complete the PDP-11
disk family Digital states disk capacities in
formatted form, that is, in terms of customeruseable storage.
RXO 1Floppy Disk Drive -The RXO 1 is a floppy

disk drive available with all PDP- 11s.Each of
these economical drives can store 256K bytes of
data in an industry-compatibleformat with up to
two drives per controller. Average access time is
483 milliseconds.
RK05J/RK05F Cartridge Disk Drives-The RK05J
and RK05F are a complementary pair of entrylevel disk products for small to medium-sized
PDP-11 systems. The RKO5J drive with removable
cartridge offers 2.5M byte of storage, and an
average access time of 70 msec. The RK05F, a
double capacity disk drive with non-removable
media, offers 5M bytes of economical on-line
storage and an average access time of 76 msec.
These disk drives can be mixed on the same controller and are N y software compatible.

RK06 Cartridge Disk Drive-The RK06 is Digital's
newest disk offering. It uses a top-loading, removable cartridge with 14M bytes of storage and has
an average access time of 50.5 msec. The RKO6 features a track-following servo mechanism for accurate positioning, error detection and correction
capability, and offset positioning retry capability
The RK06 has a dual access option.
RP04/RP05/RP06 Disk Pack Drives-The RP
family of high-capacitydisk pack drives offers both
high performance and a low price per megabyte of
storage. The RP04 is an 88M byte disk drive; the
W05 is a 88M byte disk drive that can be fieldupgraded to 176M bytes; the RP06 is a 176M byte
disk drive.
These drives use a removable disk pack and support such features as overlapped seeks,dual access,
rotational position sensing (RPS),error correction
capability (ECC),track following servo for accurate positioning, offset/retrypositioning capability,
and extensive diagnostic capability The three
drives all have a 36.3 msec average access time.
They can be mixed on the same controller and are
software compatible.
RS03/RS04 Fixed-Head Disk Drives-The RS03/
RS04 fixed head per track disk drives are ultra
high performance disks for special application
requirements. Since these are fixed-head disks,
there is no seek time involved. Their fast access
times of 8.5 msec, and data transfer rates of up to
4M bytes/sec (8Mbytes/sec on the RS04 with the
track parallel feature),make these drives ideal
for timesharing and other applicationsthat
require a significant amount of program swapping.

Whether you plan to use a large or small
PDP-11, a timesharing or a real-time operating system, Digital builds the peripherals
you need

Digital has small, low-cost disk drives, larger
models that can store a great deal of infomation, and still others that are especiallyfast

The same applies to our tape transports.

Our hardcopy and video terminals are up-todate and inexpensive.

The RS03's capacity is 5 128bytes; the RS04's is
1024Kbytes. Both drives can be mixed on the
same controller and are software compatible.

Tape Transports
Digital's selection of magnetic tape systems is just
as comprehensive. The choice ranges from the economical TS03 to the industry-compatible TU45, a
1600 bpi, nine-track drive with 75 ips tape speed.
TS03 Tape Transport-The low cost TS03 transport reads and writes tape at 12Y2 ips. It can support up to two transports using 9-track, 800 bit/in,
7-in. reels.
TE 10 Tape Transport -The larger TE 10 reads and
writes at 45 ips. It is expandable to a total of eight
drives using nine-track, 800 bpi, industrycompatible reels.
TE 16 Tape Transport -This industry-compatible
system is program-selectablebetween 800 and
1600 bpi. It can expand to a total of eight,
9-track, 45 in./sec drives.
TU45 Tape Transport- The largest PDP-11 tape
subsystem, the TU45 is similar to the TU16 system, but its drives read and write at 75 ips.
The TU45 can serve as ajournaling device for data
base management systems that require especially
high speed.

Hardcopy and Video Terminals
Digital's terminal line includes the teletypewriter-compatible DECwriter 11, the industry"~
fastest-selling impact teleprinter. The DEGwriter
operates at 30 characters per second, three times
the speed of conventional teletypewriters,yet it is
mechanically simpler and quieter than other
terminals in this category.
DECscope Series -Digital's DECscope series of
video terminals offer performance and operatororiented design that, feature for feature, make
them one of the most inexpensive sets of computer terminals on the market. These alpha-

numeric CRTs form a range of plug-compatible
devices, with each model offering additional features. Yet each model can operate on the same
communications network
A range of optional features is available for both
the DEGwriter I1 and DECscope families.

Graphics Equipment
The PDP- 11 family includes graphics systems
ranging from the low-cost W 5 5 graph drawing
terminal, to the sophisticated DECgraphic-11
line of interactive graphics terminals and
subsystems.
W 5 5 Graph Drawing Terminal -The W 5 5 is a
DECscope that displays waveform and histogram
graphics as well as alphanumerics. This makes it
a valuable tool for applications that involve data
acquisition, monitoring, trending, or simulation.
An electrolytic printer is optional. The W 5 5 can
be interfaced to any D1GIT;ALor non-DIGITAL
computer.

The DECgraphics Family
The W 11 Systems-The Wl l-A Graphics Display
Subsystem is a dynamic refresh device that is
ideally suited to interactive graphic applications.
The user interacts with the W11-A through a
light pen. A full ASCII serial input keyboard and a
16-button box under program control are both
optional.
The W11 subsystem is a direct memory access
device that operates as a UNIBUS peripheral. Thus
it can add graphics capability to any of a wide
variety of PDP- 11 configurations. There are
several W 1 1-based system packages.
The GT41 is a table top graphics terminal with
32K bytes of internal MOS memory The GT43 is a
cabinet-mounted graphics terminal package with
32K bytes of internal MOS memory and space
for considerable expansion. These are both
interactive graphics terminals.
The GT46 is a self-contained 64K-byte, dual diskbased configuration that can run the RT-11 or
RSX- 11M operating systems as a standalone
graphics system.
The VS60 Systems-The VS60 High Performance
Graphic Display Subsystem is instruction-compatible with the W11, but adds numerous sophis-

ticated features, including character and vector
scaling, windowing, clipping, and the ability to
display over 16,000inches of flicker-freevectors.
Applications can include advanced real-time data
acquisition and display, dynamic simulations,
cartography, and computer-aided design in the
electronics, aerospace, architecture, and
automobile industries.
Like the W11, the VS60 is a UNIBUS peripheral
and directly accesses PDP-11memory without
central processor overhead, leaving the C.BU free
for computational tasks.
The GT62 Graphics Terminal System combines a
VS60 Display with a PDP-11/34 processor to form
a distributed satellite terminal that can be connected to any suitable host computer. This type of
configuration lets the GT62 satellite perform realtime graphics support tasks while the host computer handles the heavy computational and data
base manipulations.

DECgraphic-11 Software
DECgraphic-11 software provides comprehensive,
high-level support for the W 1 1 and VS60 in all
their configurations. System level softwaresupport
is available for FORTRAN under RT- 11 and
RSX- 11M, BASIC and FOCAL programming under
RT- 11, and host/satellite support for FOFWRAN
under the RSX- 11M and IAS operating systems.
The DECgraphic-11 programming capability
allows easy transfer of application software from
one DECgraphic-11configuration to another.

Printers
Digital's printers are also well matched to PDP- 11
characteristics and applications.
The LA180 DECprinter-The LA180 DECprinter I
extends the DECwriter 11's field-proven technology
into higher-speed printing applications. It can
print the full 96-character ASCII upper and lower
case set across 132 columns at 180 characters per
second.

You can add on graphics equipment through
the PDP-I 1 UNIBUS, or you can install one of
our standalone graphics systems. Either way,
Digital provides comprehensive software
support

Whether you plan a large or small amount of
printing, Digital has the printers to handle i t

If you want to set up a communications network, here's the special hardware you'll
need...

The LP11 Line Printers-The LP11 line printer
series starts with a 132-column,64-character
model, the LP11-V,which operates at 300 lines per
minute. The LPl l-W version, which uses a 96character set, runs at 230 lines per minute.
The next faster LP11 model, the LP1 1-C, uses a
64-character set and runs at 900 lines per minute;
its twin with a 96-character set operates at 660
lines per minute.
The top of the line, heavy-duty LPl l-R model
prints a 64-character set at 1200lines per minute;
its 96-character twin prints at 900 lines per
minute.

Card Readers and Paper Tape Reader
There are PDP-11 card readers for users who plan
large, batch-oriented applications, as well as
smaller units for users who will have only incidental use for unit record gear.
The 300 cards-per-minute CRl 1 reader, and the
285 cards-per-minute CM 11 mark sense and
punched card reader, cover the low end. For
heavier batch requirements, PDP-11s can support
the 1000 card-per-minute CD 11with a 1000-card
hopper capacity. A larger CDl1 model provides a
1200 card-per-minute capacity and a hopper size
of 2250 cards.
The PC 11 paper tape unit reads at 300 characters
per second and punches at 50 characters
per second.

Communications Interfaces
Digital also offers a full range of asynchronous and
synchronous communications line interfaces that
allow you to economically support a single terminal
or a full network.
ASYNCHRONOUS INTERFACES-The DL1 1
single line asynchronous interface connects
PDP-11 processors to local terminals (or to remote
terminals through modems).A version of this
interface is available for LSI-1 1-basedsystems.

For multiple terminal applications, the DZ 11
eight- or 16-lineasynchronous multiplexer performs the same function as the DL1 1,but more
economically For high throughput applications,
the DH 11 16-lineprogrammable asynchronous
multiplexer is appropriate.This is a direct memory access (DMA)device that has programmable
transmission speeds and parameters.
SYNCHRONOUS INTERFACES-The DUP-11
single line asynchronous interface connects a
PDP-11 to modems handling medium-speed (up
to 9600 baud) synchronous transmission. The
DUP-11 is capable either of byte- or bit-oriented
protocol handling, so it supports Digital's Data
Communications Message Protocol (DDCMP),
IBM's Binary Synchronous (BISYNC)and Synchronous Data Link Control (SDLC)protocols, the
International Standards Organization's High
Level Data Link Control (HDLC) and ANSI's
Advanced Data Communication Control Procedure (ADCCP).The older D u l l single line synchronous interface is also available. There's a
version of the D u l l for LSI-1 1-based computer
systems.
For high throughput synchronous transmission,
there's the DQ11 single line synchronous interface. This is a direct memoxy access device that
offers optional Cyclic Redundancy Checking (CRCI
and character recognition. For multiple terminal
applications, the DV11 communicationspreprocessor supports 16communication lines,
which can be synchronous or asynchronous, intermixed on a four-linebasis.
The microprocessor-based DMC-11 is a highspeed network link between PDP- 11systems using
Digital's DDCMP protocol. The DMC-11 can handle
transmission as fast as 1 megabaud over a local
cable up to 6,000feet long, or as fast as 56 kilobaud
over an 18,000-footcable. It can operate at up to
19.2 kilobaud in remote applications using
synchronous modems. An oution allows vou to

transmit at 250 kilobaud over direct digital communications networks.
As the DMC-l 1's protocol is implemented in hardware, it offers high reliability and throughput, low
processor overhead, and ease of programming.
COMMUNICfWIONSACCESSORIES-There are
numerous other communications products for
special purposes. For applications that call for
signal conversion, the DFl 1 signal conditioning
options convert computer ('ITL) signals to EIA or
20mA signals. The DF11B integral modems convert ?TL signals to audio frequencies. DF11Bs are
also used to connect PDP- 1I s directly to Bell Data
Access Arrangements. The DN11 auto calling unit
interfaces PDP-11sto Bell 801 auto calling units.
If telegraph transmission is an application requirement, there's the DC08 and H316Telegraph
Line Interfaces. For special error detection in
seriallytransmitted data, you can attach the KG1 1
communications arithmetic element
Digital's EIA-compatible terminals can directly
connect to many of our data communications
interfaces through the H312-A null modem and
the BC03M and BC03P null modem cables.

Planning direct digital communication?
There is a n optionfor i t

There are numerous other communications
products for special purposes.

We can help you get started.

The quality of products is important, but the
quality of the organization behind them is crucial.
Digital's success is due not only to exceptional
products, but to the kind of services we offer our
customers.

Expert SystemAnalysis and Design
Before you solve a problem, you have to define it.
Digital's system analysts can help you here. They
are trained to match our systems to user needs. If
necessary, Digital can also produce custom hardware and software for particular applications.
Consulting Help From Software Services-If you
need expert software skills, Digital's Software
Services consultants have them. These specialists
can work on m y phase of any application. They do
feasibility studies and system analysis and design,
write new software, and tailor our standard software to meet specific needs. They can help you
with a crucial project, for example, or orient your
staff to newly purchased software.
Software consulting is available on a time-andmaterials basis in a variety of plans, including:
Resident Consulting-When you need a full-time,
specialist for a new, complex installation or a
long-term project, Software Servicescan provide
resident consultants.
Weekly Consulting- For short term needs, weekly
consulting provides 40 hours of on-site support.
Per-Call Consulting -Per-call consulting is
available for the user who temporarily requires a
few hours to a few days of consultants' time.

Computer Special Systems-Digital's Computer
Special Systems group (CSS)consists of analysts,
engineers, programmers, and manufacturing
specialists who build custom hardware and software for particular applications. CSS handles
everything from simple processor interfaces to
project management of complete turnkey systems.
There are CSS facilities worldwide.
Special Software- CSS will design and produce
diagnostic,systems, and applications software,
or modify standard software.
Special Systems- When you order a complete
turnkey system from CSS, project managers
oversee its analysis, design, and implementation,
and will work with you to ensure proper installation and start-up.
Support- Although CSS builds custom products,
they are fully documented, and are therefore
maintained by Digital's worldwide field service
organization.

Financing, Installation, and Training
Digital can provide financial counseling and leasing to help you acquire a system, we have project
managers that will oversee delivery and installation, and we will provide educational programs to
train your staff.
Leasing-Digital offers full payout leases that usually run from three to seven years. At the end of the
term, you may elect to buy the equipment at 10%of
the purchase price turn the system in, or continue

the lease with significantlylower payments. Lease
payment schedules are flexible and can be tailored
to your needs.
Project Management-Digital can assign a project
manager for particularly complex installations, or
those for which we have turnkey responsibility
This person works with you, your sales representative, and with Digital's hardware, software, and
service managers to see that your project goes
smoothly
Digital judges the project manager on the success
of your system. So any project manager is involved
from the beginning. He or she approves all hardware and software configurations, determines and
maintains all schedules, and coordinates testing,
training, and installation.The project manager also
arranges for special services,like software consulting, special hardware, and field service options.
Educational Services-Digital offers over 100
standard courses in system management, operations, hardware, and software at 17 training centers around the world. We also offer on-site
training and custom courses.
The courses fall into four general categories:
General interest computer science courses that
provide a technical foundation for people who wish
to gain basic computer experience.
Software systems courses that train users, programmers, and operators in operating systems,
languages and utilities. There are courses for
both beginning and advanced students.
Hardware courses that train users who plan to
service their own equipment, or those who simply
want an understanding of their hardware. There
are courses in general hardware familiarization,
hardware troubleshooting, and hardware
maintenance.
Audio-visual courses provide self-paced instruc-

use it over and over again, training large numbers
of people without the expense of travel.
Digital regularly schedules courses at our training
centers. But we also offer on-site courses for training groups at your own offices or elsewhere.On-site
instruction eliminates travel expenses, and allows
our instructors to orient the course to your
particular needs.

Field Service
Hardware Maintenance -Digital has a field service
organization of over 4000 service engineers working out of more than 300 locations throughout the
world. These field engineers are experts in Digital
hardware. Many also specialize in specific applications. The world-wide service organization behind
them insures the fastest and best possible response
to your system maintenance needs.
Digital has a wide range of hardware maintenance
services. The choices include:
ServiceAgreements-You may choose either a
Basic Agreement designed for most applications,
or a Critical ApplicationsAgreement if you require
a more intensive service program.
The Basic Agreement includes all materials and
labor, preventive maintenance, installation of
engineering changes, and flexible coverage time
based on your needs.
The Critical ApplicationsAgreement provides the
same services plus response within four hours,
continuous service until repairs are complete,
and more frequent preventive maintenance.
Per-call service is designed for installations that
are considered non-critical, have other backup
equipment, or perform first-line maintenance
themselves.
Other Services-Ifyou wish to maintain your own
equipment,we offer a variety of assistance. This
includes off-site repair of major equipment and
modules; recommended spares service, spare

There are plenty of courses to train
your people.

And worldwide hardware and software support to make sure our products pe@om.

~2%-

Join the industry 5 ?arg

parts, tool kits, and test equipment; maintenance
documentation and engineering updates; emergency parts service; and hardware maintenance
training.

Software Services
Software Services is a customer support organization that helps Digital customers get maximum results from our system software,languages,
and application packages.
Before you buy, Software Services people can give
you technical presentations on our products,
perform benchmarks, do systems analysis, and
make technical evaluations of the applications
you are considering.
When you buy software from Digital, Software
Services installs it and makes sure that it performs as stated in our software product descriptions. Software Services also corrects any problems that arise during the one-year warranty
period that covers most Digital software
products.
During the warranty period you receive:
Software Dispatch-These monthly newsletters
contain solutions to software problems, information on system enhancements and new software
products, and general software information.
Software Updates-You are informed of all new
operating system releases so that you may prepare
your operation to use them if you wish.
Performance Reports-A formal problem reporting
service provides you with responses to problem
reports.
All of these services are also available to you after
the warranty period ends.
Software Distribution Center-Digital's Software
Distribution Center (SDC)stocks over 10,000software items and documents. These include source
and binary software products on DECtape, paper

tape, disks, magnetic tape, and cassette; paper and
microfiche listings textbooks, handbooks, and
manuals. Periodic issues of the SDC price list keep
you informed of current offerings.
In addition to pre-sales and warranty/maintenance, Software Services offers consulting help,
described previously

DECUS: A Community of Fellow Users
DECUS, Digital Equipment Computer Users
Society is a voluntary, not-for-profit users group,
supported in part by Digital. It is the largest and
most active user group in the computer industry.
The objective of DECUS is to advance the art of
computation through mutual education and exchange of ideas and information. It also provides
feedback to Digital on user hardware and software
needs.
To further these gods, DECUS holds regular
symposia maintains a program library publishes
newsletters and symposia proceedings, and has a
number of special interest and local subgroups.
Syrnposia- DECUS regularly schedules meetings
of users in the United States, Canada Europe,
and Australia Papers presented at these meetings
are available to all members.
Program Library-This collection of programs
submitted by users is available to all DECUS
members. Last year, the library distributed over
80,000 programs.
Subgroups-Special interest groups focus on
operating systems, languages, processors, and
applications. There are also numerous local users
groups.

What has been termed the minicomputer revolution came about for two reasons. The balance of
minicomputer performance for the price has continually shifted in the customer's favor, and the
sophistication of minicomputer systems has
rapidly advanced.
The PDP- 11 family of products represents the
coming together of these two movements. Customers have been quick to realize that PDP-11sare
a practical choice for more and more applications,
often at enormous savings over alternate methods
of solving the problem. Digital has been equally
quick to develop tools to help customers
accomplish this.
The result is over 50,000 PDP-11 installations
crossing the spectrum of applications.With this
much experience, and the unmatched range of
PDP-11 products, we're ready to talk about the
application that interests you.

Iff'

DIGITAL EQUIPMENT CORPORATION, Corporate Headquarters: Maynard, Massachusetts 01754, Telephone: (617l897-5111 -SALES AND SERVICE OFFICES:
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KINGDOM, Birmingham, Bristol, Epsom, Edinburgh, Leeds, Leicester, London, Manchester and Reading. VENEZUELA, Caracas.

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