PDP-9

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PDP-9
DeveloperDigital Equipment Corporation
Product familyProgrammed Data Processor
TypeMinicomputer
Release date1966; 58 years ago (1966)
Units sold445
MediaPaper tape
PlatformDEC 18-bit
Mass750 pounds (340 kg)
PredecessorPDP-7
SuccessorPDP-15
A PDP-9 on display at ACONIT in Grenoble, France

The PDP-9, the fourth of the five 18-bit minicomputers produced by Digital Equipment Corporation, was introduced in 1966.[1]: P.10  A total of 445 PDP-9 systems were produced,[2] of which 40 were the compact, low-cost PDP-9/L units.[3]

History[edit]

The 18-bit PDP systems preceding the PDP-9 are the PDP-1, PDP-4 and PDP-7. Its successor is the PDP-15.

Hardware[edit]

The PDP-9, which is "two metres wide and about 75cm deep,"[4] is approximately twice the speed of the PDP-7. It was built using discrete transistors, and has an optional integrated vector graphics terminal. The PDP-9 has a memory cycle time of 1 microsecond, and weighs about 750 pounds (340 kg).[5]: 1-7–1-8  The PDP-9/L has a memory cycle time of 1.5 microseconds, and weighs about 900 pounds (410 kg).[6]: 1-1, 15-8 

It is DEC's first microprogrammed machine.[7][5]: 3-16 

A typical configuration included:[2]

Model 33 Teleprinter, similar to the PDP-9's console device, though the PDP-9 had faster dedicated paper tape devices instead of the integrated reader/punch.

Among the improvements of the PDP-9 over its PDP-7 predecessor are:

  • the addition of status flags for reader and punch errors, thus providing added flexibility and for error detection[8]
  • an entirely new design for multi-level interrupts, called the Automatic Priority Interrupt (API) option
  • a more advanced form of memory management[9]

User/university-based research projects for extending the PDP-9 include:

  • a hardware capability for floating-point arithmetic, at a time when machines in this price range used software for floating-point arithmetic[10]
  • a PDP-9 controlled parallel computer[11]

Software[edit]

The system came with an OS that functions as single-user keyboard monitor, called ADSS (ADvanced Software System).[12] DECsys provided an interactive, single-user, program development environment for Fortran and assembly language programs.[13]

Both FORTRAN II[2] and FORTRAN IV[14] were implemented for the PDP-9.

MUMPS was originally developed on the PDP-7, and ran on several PDP-9s at the Massachusetts General Hospital.

Sales[edit]

The PDP-7, of which 120 were sold,[1]: p.8  was described as "highly successful".[2] The PDP-9 sold 445 units. Both have submodels, the PDP-7A[NB 1] and the PDP-9/L,[NB 2] neither of which accounted for a substantial percentage of sales.[1][NB 3]

See also[edit]

Notes[edit]

  1. ^ sometimes identified by customers and media as PDP-7/A
  2. ^ yes, DEC had a "slash" for the 9/L but not for the 7A
  3. ^ directly mentioned for one, calculated in the other case

References[edit]

  1. ^ a b c DIGITAL EQUIPMENT CORPORATION - Nineteen Fifty-Seven To The Present (PDF). Digital Equipment Corporation. 1975.
  2. ^ a b c d "RI Computer Museum, DEC PDP-9, System Number 319".
  3. ^ ."The Early Architectures of DEC".
  4. ^ "David Millson - 50 years".
  5. ^ a b PDP-9 Maintenance Manual, Volume 1 (PDF). April 1972.
  6. ^ PDP-9/L User Handbook (PDF). June 1968.
  7. ^ C. Gordon Bell; Gerald Butler; Robert Gray; John E. McNamara; Donald Vonada; Ronald Wilson (1978). "Chapter 6: The PDP-1 and Other 18-bit Computers". In C. Gordon Bell; J. Craig Mudge; John E. McNamara (eds.). Computer Engineering: A DEC View of Hardware Systems Design. Digital Press. pp. 154–155. ISBN 0-932376-00-2.
  8. ^ Bob Supnik. "Architectural Evolution in DEC's 18b Computers" (PDF).
  9. ^ "PDP 9 Simulator Configuration". GitHub.com.
  10. ^ Ben Milton Huey (1969). Design of a floating point processor for the PDP-9 computer (MSc thesis). University of Arizona.
  11. ^ Wokhlu, Roop Krishen (1969). The logic design of a PDP-9 controlled parallel computer (MSc thesis). University of Arizona.
  12. ^ Digital Equipment Corporation. "Software Product Description, ADSS-B/F-15, Version SC, Advanced Software System, B/F" (PDF).
  13. ^ Bob Supnik (19 June 2006). "Technical Notes on DECsys" (PDF).
  14. ^ "User Manual - Linkage - PDP-9 Facilities" (PDF). Carnegie-Mellon University Hybrid Computation Laboratory. September 1968. Retrieved 19 September 2017.


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