PDP-11 Variations on aThae

This uniquely successful computer family is based the need for multiplexers or synchronizing hard- around a compatible set of processors -ranging ware. Memory and peripherals can send, receive, or from single-board microcomputers to full multi- exchange data without processor intervention and purpose computer systems. All of these processors without intermediate buffering in memory. Thus, are built upon a common architecture that uses a an I/O device can be communicating with memory similar instruction set and input/output system. at the same time the processor is performing This common architecture means you can expand computations. a PDP- 1 1 system when your workload grows, since Direct communication over the UNIBUS means the nearly all of our peripherals and software will work PDP-11 does not require separate I/O instructions. with any PDP- 1 1 processor. It also means you can The same instruction that performs a register-to- have a mix of PDP- 11 systems doing different register transfer within the central processor can things and they will be able to communicate among perform a memory to I/O device transfer, an I/O themselves.A single development and documenta- device to memory transfer, or a transfer between tion effort will support them all. But most of all, two I/O devices. this commonality means you can start today with the PDP-11 system you want, knowing it can grow Software Compatibility with you in any direction to meet tomorrow's needs. Since all PDP- 1 1 processors use the same basic in- A key factor in the PDP- 1 1family's success is that struction set, programs developed on one PDP- 11 all system elements -processor, memory, periph- are immediately usable on larger models and, by erals-plug into a UNIBUSm,a single, high-speed, using the proper coding conventions, on smaller data path. models as well. Common software means no con- version problems when you move to alarger PDP- 1 1 The UNIBUS prevents any PDP- 11 system from be- system. Programs developed on one PDP-11 will coming obsolete. Its asynchronous design allows run on other systems under the same operating the processor, memory and peripherals to operate software, regardless of the specific processor. at their own speeds. Thus, larger or faster periph- erals or memory can replace older versions without Programming Flexibility affecting the system. And since there is a com- The comprehensive PDP- 11 instruction set and patible UNIBUS on all but the smallest PDP- 11 addressing modes yield over 400 commands, pro- system, you can freely exchange peripheral devices viding the programming flexibility of a large com- from system to system. puter in a 16-bit mainframe. The set offers a wide The UNIBUS has performance advantages as well. choice of commands, so that a single instruction It gives fast devices direct memory access without frequently suffices where several would be required Digital's leadership of the minicomputer revolution neer all of our computer systems with data com- remains unchallenged. Not only has the PDP- 11 munications in mind. Then we complete the circle family redirected the path of computer technology, with a full range of communications-oriented it has become the world's most popular minicom- hardware and software. puter series in doing so. DECnet, for example, is the set of software tools that Behind this success are 20 years of technological lets our PDP- 1ls,PDP-8s, DECsystem-10s and accomplishment. Digital's small computers moved DECsystem-20s share peripherals, files, and pro- computing power beyond the data processing grams among themselves. What DECnet does is centers of large organizations for the first time. simplify start-up of almost any sort of network Today our PDP-1 1s stand at the forefront of the using Digital computers, whether you plan to link shift to distributed processing. dedicated microcomputers to a minicomputer, or Digital's PDP- 11s hold a unique position not only set up a large-scale distributed processing network because they are economical and efficient, but be- across a continent. cause they have the hardware, software, and sup- Digital customers are the beneficiaries of this sort porting services to do what computer users want to of technological pioneering. When our engineers do today break new ground, they simply widen the scope of Nothing illustrates this better than Digital's com- what you and your staff can do with the Digital mitment to data communications. First we engi- products you already have. ThePDP-11 family covers the spectrum of small to large minicomputers. Yet all PDP-11s 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-11s, guarantees that changing tech- nology won't leave your system behind It means you can easily attach larger orfaster peripherals or memory whenever you want to. The UNIBUS also makes programming easier:

All PDP-11 processors, however small or big? respond to the same set of instructions, sopro- grams writtenfor one PDP-11 can run on a larger PDP- 1 1, and vice versa. And thisset of instructions is very large, which saves programmers' time.

Fully vectored hardware interrupts, eight general registers, andfourpriority levels help PDP-1 1 s work egiciently. in a traditional computer. Larger PDP- 11 models Since these are general purpose registers, the pro- provide a superset of the basic family instruction grammer can assign them dynarnicallp depending set. on whether the need is to achieve computational The PDP- 11 family allows bit byte and word speed, manipulate a pointer, or use the registers for addressing in both single- and double-operand temporary storage. formats. This helps save memory space and simpli- Priority Scheduling fies the implementation of control and communi- PDP-11 computer systems provide four prioriQ cations applications. levels, each of which can handle an almost un- The PDP- 11 family's use of double-operand instruc- limited number of devices. The priority of a device tions allows programmers to perform several oper- is a function of the device's physical location on the ations with a singie instruction. For example,ADD UNIBUS- the closer to the processor, the higher its AB adds the contents of locationA to locationB and priority on that level. stores the result in location B. It might take three PDP-11 architecture directs the device causing the instructions to do the same thing on another intenupt(s)to provide a direct vector to its own minicomputer. service routine, eliminating the slow and tedious The PDP- 11instruction set also contains a full set operation of polling all devices to see which one of conditional branches, eliminating excessive use interrupted. of "jump" instructions. A branch is also included The device also provides status information for its for overflow of a signed integer, eliminating the own service routine. Thus, the programmer has the need for a separate subroutine. flexibility of assigning a device to a higher priority Hardware Interrupts and its service routine to a lower priority without The interrupt system for the PDP-11 is another writing special software. advance in small computer technology. With fully- vectored 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-1 I feature, not an extra-cost option. This system allows interrupts to be enabled or dis- abled, through software, during program oper- ation. 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-1 1s give the pro- grammer the flexibility of a large-scale computer. The advantages of the PDP- 11 processors are just Digital designs and builds most of this equipment a part of the PDP- 11 story however. The broadest specifically for use with our own computers. Yet, range of operating systems in the computer indus- we've become such a leading peripherals manufac- try is available for your use. The choice extends turer that you'll find them included in more and from single-user program development systems to more computer systems from other vendors. Our powerful timesharing, real-time, and multi- DECwriters, in fact, are the industry's fastest- purpose operating systems. selling hardcopy terminals. The selection of industry-standard programming For PDP-11 users, this all means an exceptionally languages is just as comprehensive. The smallest wide choice of high-quality peripherals, at excep- PDP-11s can run several versions of FORTRAN, tionally competitive prices. BASIC, and APL, while larger systems can also sup- But hardware and software are not the sum total of port COBOL and RPG 11. And many of our systems the PDP-11 family's strengths. Digital backs up its are available with a range of application software computer systems with a worldwide field service and utilities. organization of over 4,000people; a software sup- The high degree of commonality among PDP- 11 port group dedicated to helping customers with all programming languages, system programs, and their software needs; and training facilities, also data management services facilitates migration located worldwide, that offer over 100 scheduled from one operating system to anothe~;as well as the courses. 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. 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 excep- tionally wide choice of programming lan- guages, each of which is especially suited to particular tasks.

Digital has afull line of peripheral equip- ment to match thejobs you plan ...

...and the supporting services to maintain your hardware and sofhoare and to train your people. PDP-11s come inprepackaged systems to assure the right equipment mixfor yourpur- pose. All the right cables, plugs, and power suppltes are included

Digital further adapts PDP-I 1 systemsfor particular uses.

The PDP-1 l family oseers the Original Equip- ment Manufacturer a single source of supply, discount policies, and worldwidefield service. - How do you match your application plans, your Original Equipment budget, and your long range goals to a minicom- Manufacturers (OEMs) puter system? Digital takes much of the work out OEMs as well as end users can profit from Digital's of it for you. unequaled range of products. Digital is the anly Our PDP- 11 products are available in pre- computer manufacturer that can offer the OEM a configured systems. We sell these systems through single source of supply for processors, software, marketing groups that specialize in solving prob- and peripherals. lems in particular application areas. That means Digital's discount policies help OEMs offer high- your sales representative will be used to dealing quality products at competitive prices. And our with the general type of application you plan. worldwide hardware and software support aug- Your first step is choosing the PDP- 11 operating ments OEM's own servlce organizations, system that fits the type of application you have in Whether you are an end user or OEM, the PDP-11 mind. The next step is adding the processor and family structure protects your investment. 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 op- tions for PDP- 11 systems.Our Commercial Product 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- 1 1s provide the commercially oriented user with Indexed Sequen- tial 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. Nearly 50,000 PDP- 11s have been sold since the RT- 11 supports both single job (S/J)and fore- series introduction in 1970. The success of the ground/background (F/B)monitors. The F/B PDP- 11 family is not limited to anyone market area monitor allows both a foreground and background or type of application; the PDP- 11's advantages program to operate. The foreground handles real- have been enough to make it pre-eminent across an time functions and has priority on systems resour- enormous number of computing applications. ces; program development or batch jobs can operate The range and unique strengths of the PDP-11 in the background whenever the foreground is operating systems deserve major credit for this. not busy RSTS/E ushered in a whole new era of economical RT- 11 includes a variety of system and program timesharing; RT-11 let dedicated minicomputer development utilities and offers optional support test stands obsolete cumbersome industrial for FORTRAN IV, FOCAL, BASIC, APL, and MACRO relays; the RSX family of operating systems made assembler. real-time data collection and process control prac- tical and economical; MUMPS did the same for on- The Timesharing Operating System line data base information systems; IAS let users RSTS/E perform simultaneous timesharing, real-time, and RSTS/E (Resource Sharing Timesharing System/ batch processing on asingle computer.One of these Extended) provides efficient timesharing for up to operating systems was designed with your appli- 63 simultaneous users. RSTS/E supports BASIC- cation in mind. PLUS, an enhanced version of Dartmouth Standard BASIC, and optionally, BASIC-PLUS-2 RPG 11, The Single-User Operating System COBOL, FORTRAN IV, and APL. RT-11 RT- 11 is an efficient, single-user, real-time disk Each RSTS/E timesharing user can have virtually operating system for interactive program develop- the entire system's processing power, utilities, and ment and dedicated on-line applications. There are peripherals at his command during program over 4,000 RT- 11-based systems in use, making development or execution. this the world's most popular real-time operating The operating system's multitasking support gives system. it the flexibility that timesharing demands. Its The compactness and efficiency of the RT- 1 1real- dynamic scheduling algorithm allocates proces- time system allow it to run on the lowest-cost hard- sor time, memory space, file space and peripherals ware configurations, while giving full rein to a to continually keep processing efficient.The system PDP- 11 's speed. And RT- 1 1's simplicity makes it manager can also set priorities to favor specific extremely easy to program. 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-11s 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 chang- ing mix of users and protection of everyone's privacy. Even a relatively small PDP-11 sys- tem can provide timesharing service to numerous users.

Still another operating system is designed for a situation where many people want quick access to a central datcrfile stored in the com- puteralong with the ability to quickly change or update that central data base. with anumber of utilities that keep track of system for accepting or rejecting newly entered data, and usage and help in allocating system resources. for facilitating the on-line correction of data at The operating system provides all the securitylocks entry time. Other text-handling capabilities in- necessary for amulti-user timesharing environ- clude the ability to combine several pieces of text ment. Files canbe protected from access on an in- into one, and to divide text into segments if desired. dividual, group, or system basis. Files can also be The language's hierarchical file structure allows accessed by many users while being updated on- users to design data files to suit their own require- line. Total or selective flle backup can be done on- ments. This is significantbecause the data inmost line without disrupting users or it can be done off- record systems (for example, medical records, line. Other protective measures include on-line financial records, and soon) actually do have many backup/restart, installation-oriented protection different levels of importance and detail. The schemes, catalogue-oriented flle identification, and MUMPS-11 user can create file structures that removable storage media mimic the logical structure of the data. The RSTS/E's conveniences include easy-to-use system language's hierarchical flle structure also simpli- generation features, comprehensive documenta- fies storage or accessing of any given data item. tion for all levels of users, and standardized and The MUMPS- 11 language's high-level nature Is indexed error messages. suited to the kind of problems the language is used Extensive commercial and data management facil- to solve. MUMPS-11 may be used by programmers ities include ISAM (Indexed Sequential Access with relatively little training. They canproduce use- Method), relative access method, decimal arith- fulworking code from the first daythey start to pro- metic, and line printer spooling. Sort facilities in- gram, even though full utilization of MUMPS-1 1's clude aBASIC-PLUS sort package and an optional capabilities requires a substantial amount of standalone multivolume sort package. This gives programming experience. the RSTS/E user an integrated set of commercial Since MUMPS- 11 is an on-line program develop- applications development tools. ment and data storage and retrieval system, a pro- The Multi-User Data Base Management grammer can write, debug or modifl aprogram to System quickly develop aworking application. A user can MUMPS- 11 enter, inspect or change data interactively and effi- MUMPS- 11 is a multi-user data base management ciently. Since MUMPS- 11is implemented as an in- system that includes both an operatingsystem and terpreter, it eliminates the need for any time- a high-level language. The MUMPS- 11 language consuming compilation step or extra storage space was originally developed in 1968by the Laboratory for compiled code in addition to the source code. for Computer Science at the Massachusetts Data base management activities usually involve General Hospital. sensitive information at some point. Therefore, The MUMPS- 11 language has text-handling capa- safeguards must be established to allow access only bilities that facilitate the inspection of anypiece of to authorized personnel. data for content (such as particular keywords) or Each user of the MUMPS- 11 system gains access to for any format (such asletters, numbers or punctu- the system's programs using a special login se- ation characters at particular positions in a piece quence which involves one or two access codes of text). These capabilities are extremely important (depending on the privileges of the user). These codes, provided by the system manager, are the User driven, in contrast to systems which use a static Class Identifier code or UCI, and the Programmer scheduling mechanism to determine a task's eligi- Access Code or PAC. MUMPS-11 allows up to 16 bility to execute. The basis of event-driven task UCIs (classes of user). scheduling is the software priority assigned to each MUMPS- 11 also uses a concept called "tied active task When a significant event, (such as I/O terminals" as part of its approach to data security. completion) occurs, the executive interrupts the The system manager can "tie" any terminal to a executing task and searches for the highest priority given program. Simply striking a key on the tied task capable of executing. terminal will cause it to begin executing its Once a task is in memory; the executive normally assigned program. It is then impossible for the user allows it to run to completion in a multipro- to go through the login procedure. grammed fashion, even if its memory is required for All PDP- 11s can run MUMPS. A single PDP- 1 1 sys- the execution of a higher priority; non-resident tem can support up to 64 MUMPS terminals. task. However, if the system manager wants to free The Real-Time Operating System memory for execution of a higher priority task, a RSX- 11M task can be declared checkpointable when created. RSX- 11M is the primary PDP- 1 1 real-time oper- A checkpointable task currently active in a parti- ating system. It is ideal for factory automation, tion can be interrupted and swapped out of mem- laboratory data acquisition, graphics, power moni- ory to disk when a higher priority task requests its toring, and other applications that demand an partition. Later, after the higher priority task has immediate response. finished, the checkpointed task will be restored to RSX- 1 1M delivers all that these applications active execution at the point where it was require of an operating system. It supports multi- interrupted. tasking, dynamic memory management, multiple RSX-1 1M tasks can be written in MACRO assem- programming languages, interactive program de- bly language or optionally in BASIC-PLUS-2, velopment, and a wide range of equipment FORTRAN IV, FORTRAN IV-PLUS, or COBOL. interfaces. RSX- 1 1M accomplishes multiprogramming by RSX-11S logically dividing available memory into a number RSX- 11 S, a subset of RSX- 1lM, provides a dedi- of named partitions. Tasks execute in a specific cated, execute-only environment for monitoring partition, and all partitions in the system can and controlling many real-time processes concur- operate in parallel. rently Program development and RSX- 11s system RSX- 1 1M systems with the memory management generation takes place on a host RSX- 11M system, option protect the memory area assigned to a task allowing the RSX-1 1ssystem to be wholly dedi- from other tasks executing in the system. With cated to its real-time task. memory management, each task has a specific The Multifunction Operating System address range in which to execute, and can refer- IAS ence and alter memory onlywithin the area it owns. IAS, the Interactive Application System, supports Very large programs can be executed using either concurrent real-time, timesharing, and batch disk or memory overlay structures. processing, making it the ideal multipurpose oper- ating system. Since an IAS system also offers~ower- There's also real-time operating softLuare for situations where a PDP-11 has to collect, analyze and respond immediately to in- formation 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 canper- fonn 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 time- sharing service to scientists and engineers. IAS has all the capabilities to do these many differ- ent tasks well. Its extensive system management facilities equip it for real-time tasks; its compre- hensive 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 in- ternal software interface for the development and use of special-purpose, multi-user interactive appli- cations; a sophisticated file system providing device independence, file protection, sequential and random file access; dynamic allocation of sys- tem resources; use of shared, reentrant code to minimize memory requirements; system manage- ment facilities for system configuration, gener- ation, 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 facil- ities 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-2 and COBOL language processors. Digital's high-level languages let you move freely BASIC-PLUS has a comprehensive group of string among operating systems. These languages span operations that provide efficient processing of the breadth of the PDP-11 operating systems, and alphabetic data, including names, addresses, conform to the industry standards that exist. In sentences and paragraphs. The BASIC-PLUS user some cases, more than one version of a particular can append strings or compare them. It's possible language is available on a single operating system, to extract, examine, or search for a string of each optimized to meet particular requirements. characters contained within a larger string. BASIC-11 BASIC-PLUS has an immediate mode of operation BASIC- 11 is an easy-to-learn,conversational that allows commands to be immediately executed programming language that uses simple English instead of stored for later execution. BASIC-PLUS words, abbreviations, and familiar mathematical commands can also be more than one line long. symbols to perform operations. The BASIC in- BASIC-PLUS includes a set of 13commands for per- struction set contains powerful yet easy-to-learn forming matrix input/output, addition, subtrac- commands that allow novices to quickly become tion, multiplication, inversion, and transposition. accomplished applications programmers. With ex- The language also has extensions that provide a perience, programmers can start using the ad- highly efficient means of handling records com- vanced techniques available in the language to posed of fixed-length fields. perform intricate manipulations or to express a The language has program control and storage problem efficiently and concisely facilities that can store both programs and data on Digital's BASIC-1 1is an immediate response, in- any mass storage device and retrieve them for use teractive language compatible with Dartmouth during program execution. A PRINT-USING state- standard BASIC. It gives the user the capability to ment provides for tabs, spaces, and column head- develop and debug a program in a minimum ings, plus precise specifications of output line amount of time. BASIC- 11 can be used for relatively formatting and floating dollar sign, asterisk fill,and large data processing tasks as well as quick one- comma insertion in numeric output. Listings can time calculations. be on a line printer as well as on a terminal. BASIC-11 is available under RT- 11, RSTS/E, BASIC-PLUS is included with the RSTS/E RSX-11M, and IAS. operating system. BASIC-PLUS BASIC-PLUS-2 BASIC-PLUS offers many additional functions not BASIC-PLUS-2 is a superset of BASIC-PLUS with found in standard Dartmouth BASIC or most other true compilation capability. Therefore BASIC- versions of the language. PLUS-2 application programs run much faster i$& Digital 's high-level programming languages put the computer's power in theprogrammer's hands. Since these languages conform to in- dustry standards, most programmers are al- readyfamiliar with them. Each language is a tool that is good forpar- ticular kinds of projects. Whateveryour appli- cation, there's a PDP-I I programming lan- guage to match it than BASIC-PLUS programs do. BASIC-PLUS-2 FORTRAN IV-PLUS files also interface directly to the RMS- 11 record A superset of FOR'PRAN IY FORTRAN IV-PLUS sup- management system, which allows the BASIC- ports the same enhancements to the ANS standard, PLUS-2 user to create files, do record mapping, and but also includes numerous extensions. The access records sequentially, randomly; or by key. primary differences between the FORTRAN IV and BASIC-PLUS-2 also provides a CALL statement that FORTRAN IV-PLUS compilers are that the lets it access external subroutines. There are also a FORTRAN IV-PLUS compiler produces highly op- number of statements that allow the programmer timized PDP- 1 1 machine language code; creates to interactively observe and control program execu- hard code that uses the Floating Point Processor tion. BASIC-PLUS-2 is supported under the option in high-end PDP- 1 1s; and can produce RSTS/E, RSX- 11M and IAS operating systems. shareable code. COBOL FORTRAN IV-PLUS conforms to the specifications PDP- 1 1 COBOL provides terminal-oriented, fast for ANS FORTRAN X3.9-1966. It is available under data processing for commercial applications. RSTS/E, RSX- 1lM, and LAS. Source programs are written in the American APL1 1 National Standards Institute (ANS) COBOL-74 APL11 uses one of the most concise, consistent, language. PDP-11 COBOL is a fully implemented and powerful character sets ever devised. It is flex- intermediate level compiler conforming in lan- ible enough to solve problems in text-handling and guage element, representation, symbology and commercial data processing as concisely and m coding format to the ANS specification.In addition, easily as it can solve problems in mathematics and it includes a number of high-level specifications. statistics. It is available under RSTS/E and RT- 1 1. Major features include use of the Digital stan- RPG I1 dard CALL sequences for external subroutines; use RPG I1 is a complete report program generating sys- of the RMS- 11 Record Management System; an tem that provides users with a ready means of ANS standard COBOL segmentation facility; and developing applications programs. It supports ANS standard string and substring manipulation. almost all functions offered by industry versions of COBOL is an optional language processor for RPG 11, and provides significant improvements over RSTS/E, RSX- 11 M, and IAS. RPG I. It is available under RSTWE. FORTRAN IV PDP-11 SORT PDP- 1 1 FORTRAN IV is a substantially improved SORT is a fast-workingutilityprogram that lets the form of the standard scientific programming lan- user rearrange, delete, and reformat records in a guage that can be used on any PDP- 11 configu- mass storage file; select a sorting process and in- ration. New optimizations make programs small and put device that best suit the processing environ- fast. Powerful extensions permit markedly easier ment; and create new file indices for accessing a program coding. And FORTRAN IV 's compilation large data base. speed minimizes program development time. SORT also allows the user to batch stream several Since FORTRAN IV is a superset of ANS standard sorting jobs and to define specification files for FORTRAN, programs written to this standard but complex record definitions. The SORT Drograrn used on other computer systems can run un- modified under FORTRAN JY The PDP- 1 1 family provides a full range of data DBMS-11Data Base Management System management tools. The choice extends from the DBMS- 11 is a CODASYL-standard data base operating systems' file control systems to block management system that uses the 'set definition' input/output support: to sequential and relative as the basic building block with which even the logical file/record support with a multi-key index most complex data relationships can be defined. sequential option; to a complete, CODASYL- DBMS- 1 1 gives the data base administrator better standard data base management system. overall control of data. It separates data definitions Record Management System from data references and allows definition of logi- RMS-11, Digital's Record Management System, cal, applications-oriented relationships. Redun- allows user-written application programs to create, dant data is eliminated. Data protection is maxi- access, and maintain data files with efficiency mized. Program development and maintenance and economy efforts are reduced. And the data base as a whole RMS-1 1's variety of file organizations and access can be treated as a single entity rather than as a modes gives the user the ability to choose the collection of similar but unrelated information method best suited to the application. RMS- 1 1 sup- and applications. ports sequential, relative, and indexed files which DBMS- 1 1supports multi-level sequential, hierar- users can access sequentially randomly, or by key chical (tree),and network data structures, pro- The multi-keyed access option provides both viding the data base administrator with enough generic and approximate key searches. Records can flexibility to define adata base structure that accu- be either fixed or variable length. rately reflects the installation's needs. RMS-11 also includes a set of utility programs for DBMS- 1 1provides room for growth in several the creation and maintenance of files, and a set of directions. If the user needs to grow beyond a operating system routines through which records DBMS-1 1 system, the DECSYSTEM-20 and are transmitted to and from user programs. DECsystem-10 both use CODASYL-standard data RMS-11 complements DBMS-1 1,Digital's Data base management systems. This greatly simplifies Base Management System, by providing file and the task of program conversion. record handling capabilities for applications whose DBMS- 1 1is available under the IAS operating sys- size and data structures do not require the com- tem and is supported by FORTRAN IV-PLUS, plete data base management services of DBMS-1 1. COBOL, BASIC-PLUS-2, and MACRO. RMS-11is fully supported with COBQL and BASIC- PLUS-2 under RSTS/E, RSX- 1 1M and IAS. Data management services and utility soft- ware 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 1s communicate with each other; with other Digital computers, and with non- Digital computers. The PDP-11 processor family starts off with a much as 56K bytes for more extensive programs, microcomputer, includes two mid-range minicom- which can be written in a high-level language such puters, and culminates in a powerful 'supermini'. as FORTRAN IV or BASIC. Not only do these PDP- 11 models increase incre- mentally in size and power, but each model adds PDP-11/34 extra features that are appropriate for the kinds of The PDP- 1 1/34 is a midrange member of the applications its power can handle. PDP- 1 1family As a microprogrammed processor, the PDP- 1 1/34 CPU is so compact that the entire PDP-11 /O3 CPU logic is contained on two circuit boards. The PDP- 1 1/03 has been made possible through There's considerable chassis space for the use of Large Scale Integration (LSI)technology. later expansion. Digital has been able to create a chip set in the form and function of a standard PDP- 1 1yet small The PDP- 1 1/34 incorporates anumber of large enough to be packaged along with 8K bytes of processor features which increase its capabilities memory on a single circuit board. The PDP-11/03 beyond those found in other computers in its class. includes the chassis, operator's console, processor, These features include: integral memory manage- memory, backpanel with expansion space, power ment hardware that provides program protection, supply and interface modules. memory relocation and addressing of up to 256K bytes, and integral extended instruction set (EIS) The PDP- 1 1/03 features a full PDP-11 instruction that provides hardware fixed-point arithmetic in set, vectored interrupts, an asynchronous, bidirec- double-precisionmode (32-bitoperands). A tional bus, microcoded debugging facilities, oper- floating point processor is optional. ator interface and bootstrap loader, real-time clock input, and power-fail/auto restart. PDP-11/55 The PDP- 1 1/55 is especially designed for fast exe- PDP-11/O4 cution of FORTRAN compiled tasks, whether for The PDP- 1 1/04 is a low-cost system for data acqui- critical process control, laboratory simulation sition, converting analog signals to digital signals, experiments, engineering and scientific calcula- analyzing pulse heights, storing accumulated data tions, or other applications of this kind. on magnetic tape, and other dedicated applica- Overlapped operations and high-speed com- tions. It is the smallest PDP-11 with a UNIBUS. ponents give the 11/55 its high performance. The The PDP-11/04 can have as little as 16K bytes of processor takes full advantage of such advanced memory for straightforward applications, or as components as bipolar memory, a high-speed Digital has been aleader in the trend towards inter- DICAM active computing and distributed processing. As a DICAM (Datasystem Interactive Communications result, we provide a particularly useful range of Access Method) is a software package that lets our communications software. PDP- 1 1-based DEC Datasystems communicate interactivelywith application programs on an IBN DECnet 360/370 host. DICAM does this by providing a DECnet is the set of software tools that allow communications path that makes the Datasystem Digital computer systems -PDP-8s, PDP- 11s, communicate like an IBM 327 1remote display con- DECsystem-10s and DECSYSTEM-20s- to com- troller on an IBM system. That means an IBM host municate programs and data among themselves. can support a Datasystem as easily as a standard DECnet allows different Digital computers within host option, leaving you free to take advantage of a network to control and use remote peripherals as the full range of 360/370 access methods, oper- if they were local, to access remote files, and to send ating systems, and system management packages. programs to another system for loading and execu- Remote Job Entry Packages tion. In other words, DECnet provides device shar- Digital has an assortment of remotejob entrypack- ing, file sharing, and program sharing. ages for non-Digital mainframes. An IBM 2780 emulator,an IBM HASP emulator, a Control Data This means DECnet lets you store information on Corporation UT200 emulator, and aSpenyUNIVAC one computer system, then down-line load it to 1004emulator are all available. other computer systems in your networkwhen they request it. Similarly DECnet's support for down- line system commands lets programs in one com- puter system send directives to other computer systems within anetwork.

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. The PDP-11 processorfamily starts oflwith a microcomputer;goes up through medium- scale minicomputers and culminates in a poweflul "supemini." Each larger PDP-I 1 model adds extrafea- tures that complement its increased pel3fonnance. (5.43microsecond 64-bit double precision multi- PDP-11/70 ply) double precision floating point processor, and The PDP-11/70 provides the highest throughput hardware memory management. of any PDP- 1 1 system. Its performance can be Overlapping occurs on several levels: instruction applied to applications involving many concur- pipelining,where the next program instruction is rent processes, or to a demanding single process. fetched while the current one executes; CPU For example the 1 1/70 is ideally suited for a col- independent floating point calculation; and a bus lege computer center where it can simultaneously structure that allows direct memory access with- handle laboratory data acquisition, interactive out cycle stealing on the UNIBUS. student programming, and administrative batch processing. In its smaller configurations, the 11/70 PDP-11/6O is appropriate for very demanding single-function The PDP-11/60 is a midrange system that offers applications such as timesharing or dedicated performance and reliability features usually found real-time applications. only in larger, more expensive systems. The 11/60 The unique feature of this computer is the provides a cache memory system; abuilt-in floating throughput you get for the price. This means fast point unit; an optional high speed floating point instruction processing, fast memory (an integral accelerator for fast execution speed in heavily cache memory system yields an effective memory computational applications; and an optional cycle time of less than 400 nanoseconds, while writeable control store (WCS)for special-purpose main memory is ECC MOS or parity core),fast microprogramming. 32-bit I/O paths that complement the UNIBUS, This combination of features makes the 11/60 and high-speed mass storage devices. ideal for midrange, real-time applications includ- The PDP- 11/70 is compatible with the full line of ing scientific and industrial data acquisition PDP- 11s and includes all the features that have and control, problem solving in engineering de- made the PDP- 11 family the world's fastest selling partments, simulation, medical processing, and small computer family 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-absorb- ing 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- 1 1 peripherals range from paper tape readers RK06 Cartridge Disk Drive-The RK06 is Digital's to high speed disk packs, from small auxiliary newest disk offering. It uses a top-loading, remov- printers to full graphics subsystems, from A/D able cartridge with 14M bytes of storage and has converters to heavy duty industrial controllers. an average access time of 50.5 msec. The RKO6 fea- Disk Drives tures a track-following servo mechanism for accu- rate positioning, error detection and correction Digital's disk family is comprehensive enough to capability, and offset positioning retry capability provide appropriate on-line storage for the broad The RK06 has a dual access option. range of PDP- 11 systems and their applications. The current disk product line consists of the RXO1 RP04/RP05/RP06 Disk Pack Drives-The RP floppy disk for small systems, the RK05J/RK05F family of high-capacity disk pack drives offers both and the RK06 cartridge disks for small to medium- high performance and a low price per megabyte of sized PDP- 11 systems, and the W04/RP05/W06 storage.TheRP04 is an 88M byte disk drive; the disk pack drives for large systems. The RS03/RS04 W05 is a 88M byte disk drive that can be field- head per track disk drives complete the PDP- 11 upgraded to 176M bytes; the RP06 is a 176M byte disk family Digital states disk capacities in disk drive. formatted form, that is, in terms of customer- useable storage. These drives use a removable disk pack and sup- port such features as overlapped seeks, dual access, RXO1Floppy Disk Drive -TheRXO1 is afloppy rotational position sensing (RPS),error correction disk drive available with all PDP- 11s. Each of capability (ECC),track following servo for accu- these economical drives can store 256K bytes of rate positioning, offset/retry positioning capability, data in an industry-compatibleformat with up to and extensive diagnostic capability The three two drives per controller. Average access time is drives all have a 36.3 msec average access time. 483 milliseconds. They can be mixed on the same controller and are software compatible. RK05J/RK05F Cartridge Disk Drives-The RK05J and RK05F are a complementary pair of entry- RS03/RS04 Fixed-Head Disk Drives-The RS03/ level disk products for small to medium-sized RS04 fixed head per track disk drives are ultra PDP-11 systems. The RKO5 J drive with removable high performance disks for special application cartridge offers 2.5M byte of storage, and an requirements. Since these are fixed-head disks, average access time of 70 msec. The RK05F, a there is no seek time involved. Their fast access double capacity disk drive with non-removable times of 8.5 msec, and data transfer rates of up to media, offers 5M bytes of economical on-line 4M bytes/sec (8M bytes/sec on the RS04 with the storage and an average access time of 76 msec. track parallel feature),make these drives ideal These disk drives can be mixed on the same con- for timesharing and other applications that troller and are Nysoftware compatible. require a significant amount of program swapping. Whether you plan to use a large or small PDP-11, a timesharing or a real-time oper- ating system, Digital builds the peripherals you need

Digital has small, low-cost disk drives, larger models that can store a great deal of infoma- tion, and still others that are especiallyfast The same applies to our tape transports.

Our hardcopy and video terminals are up-to- date and inexpensive. The RS03's capacity is 5 128bytes; the RS04's is numeric CRTs form a range of plug-compatible 1024K bytes. Both drives can be mixed on the devices, with each model offering additional fea- same controller and are software compatible. tures. Yet each model can operate on the same communications network Tape Transports A range of optional features is available for both Digital's selection of magnetic tape systems is just the DEGwriter I1 and DECscope families. as comprehensive. The choice ranges from the eco- nomical TS03 to the industry-compatible TU45, a 1600 bpi, nine-track drive with 75 ips tape speed. TS03 Tape Transport-The low cost TS03 trans- port reads and writes tape at 12Y2 ips. It can sup- port 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, industry- compatible reels. TE 16 Tape Transport -This industry-compatible system is program-selectable between 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 sys- tem, 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 teletype- writer-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 operator- oriented design that, feature for feature, make them one of the most inexpensive sets of com- puter terminals on the market. These alpha- - - - Graphics Equipment ticated features, including character and vector The PDP- 11 family includes graphics systems scaling, windowing, clipping, and the ability to ranging from the low-cost W55 graph drawing display over 16,000 inches of flicker-free vectors. terminal, to the sophisticated DECgraphic-11 Applications can include advanced real-time data line of interactive graphics terminals and acquisition and display, dynamic simulations, subsystems. cartography, and computer-aided design in the W55 Graph Drawing Terminal -The W55 is a electronics, aerospace, architecture, and DECscope that displays waveform and histogram automobile industries. graphics as well as alphanumerics. This makes it Like the W11, the VS60 is a UNIBUS peripheral a valuable tool for applications that involve data and directly accesses PDP- 11 memory without acquisition, monitoring, trending, or simulation. central processor overhead, leaving the C.BU free An electrolytic printer is optional. The W55 can for computational tasks. be interfaced to any D1GIT;AL or non-DIGITAL The GT62 Graphics Terminal System combines a computer. VS60 Display with a PDP- 1 1/34 processor to form The DECgraphics Family a distributed satellite terminal that can be con- The W11 Systems-The Wl l-A Graphics Display nected to any suitable host computer. This type of Subsystem is a dynamic refresh device that is configuration lets the GT62 satellite perform real- ideally suited to interactive graphic applications. time graphics support tasks while the host com- The user interacts with the W11-A through a puter handles the heavy computational and data light pen. A full ASCII serial input keyboard and a base manipulations. 16-button box under program control are both DECgraphic-11Software optional. DECgraphic-1 1 software provides comprehensive, The W11 subsystem is a direct memory access high-level support for the W11 and VS60 in all device that operates as a UNIBUS peripheral. Thus their configurations. System level software support it can add graphics capability to any of a wide is available for FORTRAN under RT- 11 and variety of PDP- 11 configurations. There are RSX- 11 M, BASIC and FOCAL programming under several W11-based system packages. RT- 11, and host/satellite support for FOFWRAN The GT41 is a table top graphics terminal with under the RSX- 11M and IAS operating systems. 32K bytes of internal MOS memory The GT43 is a The DECgraphic-1 1 programming capability cabinet-mounted graphics terminal package with allows easy transfer of application software from 32K bytes of internal MOS memory and space one DECgraphic-1 1 configuration to another. for considerable expansion. These are both Printers interactive graphics terminals. Digital's printers are also well matched to PDP- 11 The GT46 is a self-contained 64K-byte, dual disk- characteristics and applications. based configuration that can run the RT-11 or The LA180 DECprinter-The LA180 DECprinter I RSX- 11M operating systems as a standalone extends the DECwriter 11's field-proven technology graphics system. into higher-speed printing applications. It can The VS60 Systems-The VS60 High Performance print the full 96-character ASCII upper and lower Graphic Display Subsystem is instruction-com- case set across 132 columns at 180 characters per patible with the W11, but adds numerous sophis- 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 it

If you want to set up a communications net- work, here's the special hardware you'll need... The LP11 Line Printers-The LP11 line printer For multiple terminal applications, the DZ 11 series starts with a 132-column,64-character eight- or 16-lineasynchronous multiplexer per- model, the LP11-V, which operates at 300 lines per forms the same function as the DL1 1,but more minute. The LPl l-W version, which uses a 96- economically For high throughput applications, character set, runs at 230 lines per minute. the DH 11 16-lineprogrammable asynchronous The next faster LP11 model, the LP1 1-C, uses a multiplexer is appropriate.This is adirect mem- 64-character set and runs at 900 lines per minute; ory access (DMA)device that has programmable its twin with a 96-character set operates at 660 transmission speeds and parameters. lines per minute. SYNCHRONOUS INTERFACES -The DUP- 1 1 The top of the line, heavy-duty LPl l-R model single line asynchronous interface connects a prints a 64-character set at 1200 lines per minute; PDP-11 to modems handling medium-speed (up its 96-character twin prints at 900 lines per to 9600 baud) synchronous transmission. The minute. DUP-11 is capable either of byte- or bit-oriented protocol handling, so it supports Digital's Data Card Readers and Paper Tape Reader Communications Message Protocol (DDCMP), There are PDP-11 card readers for users who plan IBM's Binary Synchronous (BISYNC) and Syn- large, batch-oriented applications, as well as chronous Data Link Control (SDLC)protocols, the smaller units for users who will have only inci- International Standards Organization's High dental use for unit record gear. Level Data Link Control (HDLC)and ANSI's The 300 cards-per-minute CRl 1 reader, and the Advanced Data Communication Control Proce- 285 cards-per-minute CM 11 mark sense and dure (ADCCP).The older Dull single line syn- punched card reader, cover the low end. For chronous interface is also available. There's a heavier batch requirements, PDP- 1 1s can support version of the Dull for LSI-1 1-based computer the 1000 card-per-minute CD 11 with a 1000-card systems. hopper capacity. A larger CDl1 model provides a For high throughput synchronous transmission, 1200 card-per-minute capacity and a hopper size there's the DQ11 single line synchronous inter- of 2250 cards. face. This is a direct memoxy access device that The PC 1 1 paper tape unit reads at 300 characters offers optional Cyclic Redundancy Checking (CRCI per second and punches at 50 characters and character recognition. For multiple terminal per second. applications, the DV11 communications pre- processor supports 16communication lines, Communications Interfaces which can be synchronous or asynchronous, in- Digital also offers a full range of asynchronous and termixed on a four-line basis. synchronous communications line interfaces that The microprocessor-based DMC- 1 1 is a high- allow you to economically support a single terminal speed network link between PDP- 11 systems using or a full network. Digital's DDCMP protocol. The DMC- 11 can handle ASYNCHRONOUS INTERFACES -The DL1 1 transmission as fast as 1 megabaud over a local single line asynchronous interface connects cable up to 6,000 feet long, or as fast as 56 kilobaud PDP- 1 1 processors to local terminals (or to remote over an 18,000-foot cable. It can operate at up to terminals through modems).A version of this 19.2 kilobaud in remote applications using interface is available for LSI-1 1-based systems. synchronous modems. An oution allows vou to transmit at 250 kilobaud over direct digital com- munications networks. As the DMC-l 1's protocol is implemented in hard- ware, it offers high reliability and throughput, low processor overhead, and ease of programming. COMMUNICfWIONS ACCESSORIES- 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 con- vert ?TL signals to audio frequencies. DF11Bs are also used to connect PDP- 1Is directly to Bell Data Access Arrangements. The DN11 auto calling unit interfaces PDP-1 1sto Bell 801 auto calling units. If telegraph transmission is an application re- quirement, there's the DC08 and H3 16Telegraph Line Interfaces. For special error detection in serially transmitted 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 H3 12-A null modem and the BC03M and BC03P null modem cables. Planning direct digital communication? There is an optionfor it

There are numerous other communications products for special purposes. We can help you get started. The quality of products is important, but the Computer Special Systems- Digital's Computer quality of the organization behind them is crucial. Special Systems group (CSS)consists of analysts, Digital's success is due not only to exceptional engineers, programmers, and manufacturing products, but to the kind of services we offer our specialists who build custom hardware and soft- customers. ware for particular applications. CSS handles everything from simple processor interfaces to Expert SystemAnalysis and Design project management of complete turnkey systems. Before you solve a problem, you have to define it. There are CSS facilities worldwide. Digital's system analysts can help you here. They are trained to match our systems to user needs. If Special Software- CSS will design and produce necessary, Digital can also produce custom hard- diagnostic, systems, and applications software, ware and software for particular applications. or modify standard software. Consulting Help From Software Services- If you Special Systems- When you order a complete need expert software skills, Digital's Software turnkey system from CSS, project managers Services consultants have them. These specialists oversee its analysis, design, and implementation, can work on myphase of any application. They do and will work with you to ensure proper installa- feasibility studies and system analysis and design, tion and start-up. write new software, and tailor our standard soft- ware to meet specific needs. They can help you Support- Although CSS builds custom products, with a crucial project, for example, or orient your they are fully documented, and are therefore staff to newly purchased software. maintained by Digital's worldwide field service organization. Software consulting is available on atime-and- materials basis in a variety of plans, including: Financing, Installation, and Training Resident Consulting-When you need a full-time, Digital can provide financial counseling and leas- specialist for anew, complex installation or a ing to help you acquire a system, we have project long-term project, Software Services can provide managers that will oversee delivery and installa- resident consultants. tion, and we will provide educational programs to Weekly Consulting- For short term needs, weekly train your staff. consulting provides 40 hours of on-site support. Leasing-Digital offers full payout leases that usu- Per-Call Consulting -Per-call consulting is ally run from three to seven years. At the end of the available for the user who temporarily requires a term, you may elect to buy the equipment at 10%of few hours to a few days of consultants' time. the purchase price turn the system in, or continue the lease with significantly lower payments. Lease use it over and over again, training large numbers payment schedules are flexible and can be tailored of people without the expense of travel. to your needs. Digital regularly schedules courses at our training Project Management-Digital can assign a project centers. But we also offer on-site courses for train- manager for particularly complex installations, or ing groups at your own offices or elsewhere. On-site those for which we have turnkey responsibility instruction eliminates travel expenses, and allows This person works with you, your sales represen- our instructors to orient the course to your tative, and with Digital's hardware, software, and particular needs. service managers to see that your project goes smoothly Field Service Digital judges the project manager on the success Hardware Maintenance -Digital has a field service of your system. So any project manager is involved organization of over 4000 service engineers work- from the beginning. He or she approves all hard- ing out of more than 300 locations throughout the ware and software configurations, determines and world. These field engineers are experts in Digital maintains all schedules, and coordinates testing, hardware. Many also specialize in specific applica- training, and installation.The project manager also tions. The world-wide service organization behind arranges for special services,like software consult- them insures the fastest and best possible response ing, special hardware, and field service options. to your system maintenance needs. Digital has a wide range of hardware maintenance Educational Services- Digital offers over 100 services. The choices include: standard courses in system management, opera- tions, hardware, and software at 17training cen- Service Agreements-You may choose either a ters around the world. We also offer on-site Basic Agreement designed for most applications, training and custom courses. or a Critical ApplicationsAgreement if you require a more intensive service program. The courses fall into four general categories: The Basic Agreement includes all materials and General interest computer science courses that labor, preventive maintenance, installation of provide a technical foundation for people who wish engineering changes, and flexible coverage time to gain basic computer experience. based on your needs. Software systems courses that train users, pro- The Critical Applications Agreement provides the grammers, and operators in operating systems, same services plus response within four hours, languages and utilities. There are courses for continuous service until repairs are complete, both beginning and advanced students. and more frequent preventive maintenance. Hardware courses that train users who plan to Per-call service is designed for installations that service their own equipment, or those who simply are considered non-critical, have other backup want an understanding of their hardware. There equipment, or perform first-line maintenance are courses in general hardware familiarization, themselves. hardware troubleshooting, and hardware Other Services-Ifyou wish to maintain your own maintenance. equipment, we offer a variety of assistance. This Audio-visual courses provide self-paced instruc- 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 sup- port to make sure our products pe@om. ~2%- Join the industry5?arg parts, tool kits, and test equipment; maintenance tape, disks, magnetic tape, and cassette; paper and documentation and engineering updates; emer- microfiche listings textbooks, handbooks, and gency parts service; and hardware maintenance manuals. Periodic issues of the SDC price list keep training. you informed of current offerings. Software Services In addition to pre-sales and warranty/mainte- Software Services is a customer support organi- nance, Software Services offers consulting help, zation that helps Digital customers get maxi- described previously mum results from our system software, languages, DECUS: A Community of Fellow Users and application packages. DECUS, Digital Equipment Computer Users Before you buy, Software Services people can give Society is a voluntary, not-for-profit users group, you technical presentations on our products, supported in part by Digital. It is the largest and perform benchmarks, do systems analysis, and most active user group in the computer industry. make technical evaluations of the applications The objective of DECUS is to advance the art of you are considering. computation through mutual education and ex- When you buy software from Digital, Software change of ideas and information. It also provides Services installs it and makes sure that it per- feedback to Digital on user hardware and software forms as stated in our software product descrip- needs. tions. Software Services also corrects any prob- To further these gods, DECUS holds regular lems that arise during the one-year warranty symposia maintains a program library publishes period that covers most Digital software newsletters and symposia proceedings, and has a products. number of special interest and local subgroups. During the warranty period you receive: Syrnposia- DECUS regularly schedules meetings Software Dispatch-These monthly newsletters of users in the United States, Canada Europe, contain solutions to software problems, informa- and Australia Papers presented at these meetings tion on system enhancements and new software are available to all members. products, and general software information. Program Library-This collection of programs submitted by users is available to all DECUS Software Updates-You are informed of all new members. Last year, the library distributed over operating system releases so that you may prepare 80,000programs. your operation to use them if you wish. Subgroups-Special interest groups focus on Performance Reports-A formal problem reporting operating systems, languages, processors, and service provides you with responses to problem applications. There are also numerous local users reports. groups. 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 10,000soft- ware items and documents. These include source and binary software products on DECtape, paper What has been termed the minicomputer revolu- tion came about for two reasons. The balance of minicomputer performance for the price has con- tinually 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. Cus- tomers 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 50,000PDP-11 installations crossing the spectrum of applications.With this much experience, and the unmatched range of PDP- 1 1 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: UNITED STATES-ALABAMA, Huntsville ARIZONA, Phoenix and Tucson CALIFORNIA, El SegundO, Los Angeles, Oakland, Ridgecrest San Diego, San Fran- g cisco (Mountain View), Santa Ana, Santa Clara, Stanford, Sunnyvale and Woodland Hills COLORADO, Englewood CONNECTICUT, Fairfield and Meriden $: DISTRICT OF COLUMBIA. 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