The CDC 1700 was a 16-bit word

minicomputer A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...

, manufactured by the

Control Data Corporation Control Data Corporation (CDC) was a mainframe and supercomputer firm. CDC was one of the nine major United States computer companies through most of the 1960s; the others were IBM, Burroughs Corporation, DEC, NCR, General Electric, Honeywel ...

with deliveries beginning in May 1966. Over the years there were several versions. The original 1700 was constructed using air-cooled

CDC 6600 The CDC 6600 was the flagship of the 6000 series of mainframe computer systems manufactured by Control Data Corporation. Generally considered to be the first successful supercomputer, it outperformed the industry's prior recordholder, the IBM ...

-like cordwood logic modules and

core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central ...

, although later models used different technology. The final models, called Cyber-18, added four general-purpose registers and a number of instructions to support a

time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence a ...

operating system.

Hardware

The 1700 used

ones' complement The ones' complement of a binary number is the value obtained by inverting all the bits in the binary representation of the number (swapping 0s and 1s). The name "ones' complement" (''note this is possessive of the plural "ones", not of a sing ...

arithmetic and an

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because of ...

-based

character set Character encoding is the process of assigning numbers to graphical characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using digital computers. The numerical values that ...

, and supported memory write protection on an individual word basis. It had one general-purpose

register Register or registration may refer to: Arts entertainment, and media Music * Register (music), the relative "height" or range of a note, melody, part, instrument, etc. * ''Register'', a 2017 album by Travis Miller * Registration (organ), th ...

and two indexing registers (one of which was implemented as a dedicated memory location). The

instruction set In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ' ...

was fairly simple and supported seven storage

addressing mode Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions in ...

s, including multilevel (chained) indirect addressing. Although described as a 16-bit system, the basic core storage memory was 4,096 18-bit words, each comprising * 16 data bits * a parity bit, and * a program protection bit;
memory could be expanded to 32,768 words; I/O was in units of 8 or 16 bits.

Peripherals

Available peripherals included teletypewriters,

paper tape Five- and eight-hole punched paper tape Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop Punched tape or perforated paper tape is a form of data storage ...

readers/punches,

punched card A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...

readers/punches,

line printer A line printer prints one entire line of text before advancing to another line. Most early line printers were impact printers. Line printers are mostly associated with unit record equipment and the early days of digital computing, but the ...

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magne ...

drives, magnetic drums, fixed and removable

magnetic disk Magnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetizable material to store data and is a form of non-volatile memory. The information is ac ...

drives, display terminals, communications controllers, Digigraphic display units, timers, etc. These interfaced to the processor using unbuffered

interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, ...

-driven "A/Q" channels or buffered Direct Storage Access channels.

Software

The main operating systems for the 1700 were the Utility System, which usually took the form of several punched paper tapes (

resident monitor In computing, a resident monitor is a type of system software program that was used in many early computers from the 1950s to 1970s. It can be considered a precursor to the operating system. The name is derived from a program which is always pres ...

plus utilities), a similar Operating System for larger configurations (often including

punched cards A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to d ...

and

), and the Mass Storage Operating System (MSOS) for disk-based systems. An assembler and a Fortran compiler were available.

Pascal Pascal, Pascal's or PASCAL may refer to: People and fictional characters * Pascal (given name), including a list of people with the name * Pascal (surname), including a list of people and fictional characters with the name ** Blaise Pascal, Fren ...

was also available, via a

cross compiler A cross compiler is a compiler capable of creating executable code for a platform other than the one on which the compiler is running. For example, a compiler that runs on a PC but generates code that runs on an Android smartphone is a cross ...

on a

CDC 6000 series The CDC 6000 series is a discontinued family of mainframe computers manufactured by Control Data Corporation in the 1960s. It consisted of the CDC 6200, CDC 6300, CDC 6400, CDC 6500, CDC 6600 and CDC 6700 computers, which were all extremely rapid a ...

host. The Cyber 18 series, exploiting the extended instruction set, ran a disk-based OS, the Interactive Terminal Oriented System (ITOS). This system supported Fortran, Cobol, and

UCSD Pascal UCSD Pascal is a Pascal programming language system that runs on the UCSD p-System, a portable, highly machine-independent operating system. UCSD Pascal was first released in 1977. It was developed at the University of California, San Diego (UCS ...

. ITOS was a foreground/background system with multiple users connected via serial CRT terminals; user tasks ran in the background while the operating system itself ran in the foreground.

Market acceptance

The 1700 series found use as communications concentrators, Digigraphics

workstation A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workstat ...

s, remote

batch job Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...

entry stations, and industrial

process control An industrial process control in continuous production processes is a discipline that uses industrial control systems to achieve a production level of consistency, economy and safety which could not be achieved purely by human manual control. I ...

lers. One application, running the AUTRAN program, controlled water and wastewater treatment plants for many years. Another was used as Maintenance and Diagnostic SubSystem (M&DSS) for the AN/FPQ-16 Perimeter Acquisition Radar Attack Characterization System (PARCS), located at Cavalier Air Force Station (CAFS) in North Dakota; this CDC 1700 is still being used as of this writing (2016). Washington, DC used a Control Data 1700 in vote-tallying. CDC's 1700 was also used by

Ticketron Ticketron was a computerized event ticketing company that was in operation from the 1960s until 1990. It was the industry leader until overtaken by Ticketmaster. In 1990, the majority of Ticketron's assets and business were sold and the following ye ...

as central servers for their wagering systems and ticketing services.

Simulation

In mid-2016, John Forecast added a CDC 1700 simulator to the

SIMH SIMH is a free and open source, multi-platform multi-system emulator. It is maintained by Bob Supnik, a former DEC engineer and DEC vice president, and has been in development in one form or another since the 1960s. History SIMH was based on ...

package.

Photos

CDC 1700 Control Panel

Control Data 1700

References

Philips Technical Review, Volume 36, 1976, No., p.162 ff. Computer-aided design by Peter Blume: An early application of the CDC 1700 Digigraphic: shows in Fig. 4 a complete schematic of the computer configuration and in Fig. 5 a picture of the Digigraphic display Abstract:.... Work has been in progress at the Philips Laboratories in Hamburg since 1973 ... on an integrated computer system in which parts are completely detailed in a dialogue between the designer and a computer via an "interactive display" ... The mentioned display is the display of the CDC 1700 Digigraphic. Fig. 4 Figure caption: The CDC 1700 Digigraphic computer system for the graphic processing of data. The interactive display is connected to the CD 1704 central processor via a control unit with a "picture store"; the computer itself has the usual mass stores and peripheral equipment. Information from the computer store can be displayed on the screen of the picture tube and can be altered or added to by using a light pen and keyboards connected to the interactive display. This means that very fast input of both alphanumeric and graphic information is possible, while the input can be verified immediately on the screen.

External links

CDC 1700 Reference Manual (September 1965)
{{Control Data Corporation 1700