PDP-4

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PDP-4
PDP-4 wordmark.svg
Photograph of Exhibit of PDP-4 Digital Equipment Corporation Machines on the Stage of the National Archives Auditorium, 1964 (3874706978).jpg
The PDP-4 on display at NARA's auditorium stage in Washington, D.C., 1964
Developer Digital Equipment Corporation
Product family Programmed Data Processor
Type Minicomputer
Release date1962;62 years ago (1962)
Introductory priceUS$65,000(equivalent to $654,719 in 2023)
Units soldApproximately 54
Media Paper tape
Platform DEC 18-bit
Mass1,090 pounds (490 kg)
Predecessor PDP-1
Successor PDP-7

The PDP-4 was the successor to the Digital Equipment Corporation's PDP-1.

Contents

History

This 18-bit machine, first shipped in 1962, [1] was a compromise: "with slower memory and different packaging" than the PDP-1, but priced at $65,000 - less than half the price of its predecessor. [2] :p.4 All later 18-bit PDP machines (7, 9 and 15) are based on a similar, but enlarged instruction set, more powerful than, but based on the same concepts as, the 12-bit PDP-5/PDP-8 series.

Approximately 54 were sold. [2]

Hardware

The PDP-4's console typewriter was a Teletype Model 28 ASR, with a built in paper tape reader and paper tape punch. Teletype Model 28 KSR Keyboard.png
The PDP-4's console typewriter was a Teletype Model 28 ASR, with a built in paper tape reader and paper tape punch.

The system's memory cycle is 8 microseconds, compared to 5 microseconds for the PDP-1. [3] [4]

The PDP-4 weighs about 1,090 pounds (490 kg). [5]

Mass storage

Both the PDP-1 and the PDP-4 were introduced as paper tape-based systems. [6] The only use, if any, for IBM-compatible 200 BPI or 556 BPI magnetic tape [7] was for data. The use of "mass storage" drums - not even a megabyte and non-removable - were an available option, but were not in the spirit of the “personal” or serially shared systems that DEC offered.

It was in this setting that DEC introduced DECtape, initially called "MicroTape", for both the PDP-1 and PDP-4.

Software

DEC provided an editor, an assembler, and a FORTRAN II compiler. [3] The assembler was different from that of the PDP-1 in two ways:

Photos

See also

Related Research Articles

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References

  1. Robert Slater (1989). Portraits in Silicon. p.  210. ISBN   0262691310.
  2. 1 2 DIGITAL EQUIPMENT CORPORATION - Nineteen Fifty-Seven To The Present (PDF). Digital Equipment Corporation. 1975.
  3. 1 2 Paul E. Ceruzzi (2012). A History of Modern Computing . p.  209. ISBN   978-0262532037.
  4. Bell, C. Gordon; Mudge, J. Craig; McNamara, John E. (2014). Computer Engineering: A DEC View of Hardware Systems Design. ISBN   978-1483221106.
  5. Weik, Martin H. (Jan 1964). "PROGRAMMED DATA PROCESSOR 4". ed-thelen.org. A Fourth Survey of Domestic Electronic Digital Computing Systems.
  6. Bob Supnik. "Architectural Evolution in DEC's 18b Computers" (PDF).
  7. Brochure F-71 - "Programmed Data Processor - 7" (PDF). Digital Equipment Corporation. 1964.