PDP-15 explained

PDP-15
Developer:Digital Equipment Corporation
Family:Programmed Data Processor
Type:Minicomputer
Lifespan:1979
Unitssold:790[1]
Os:DECsys, RSX-15, XVM/RSX, MUMPS, DOS-15[2]
Platform:DEC 18-bit
Predecessor:PDP-9

The PDP-15 was the fifth and last of the 18-bit minicomputers produced by Digital Equipment Corporation. The PDP-1 was first delivered in December 1959[3] and the first PDP-15 was delivered in February 1970.[4] More than 400 of these successors to the PDP-9 (and 9/L) were ordered within the first eight months.[3]

In addition to operating systems, the PDP-15 has compilers for Fortran[5] and ALGOL.[6]

History

The 18-bit PDP systems preceding the PDP-15 were named PDP-1, PDP-4, PDP-7 and PDP-9.The last PDP-15 was produced in 1979.

Hardware

The PDP-15 was DEC's only 18-bit machine constructed from TTL integrated circuits rather than discrete transistors, and, like every DEC 18-bit system could be equipped with:

Models

The PDP-15 models offered by DEC were:[8] [9] [10] [11]

PDP-15/76

Software

DECsys, RSX-15, and XVM/RSX were the operating systems supplied by DEC for the PDP-15. A batch processing monitor (BOSS-15: Batch Operating Software System) was also available.[6]

DECsys

The first DEC-supplied mass-storage operating system available for the PDP-15 was DECsys, an interactive single-user system. This software was provided on a DECtape reel, of which copies were made for each user. This copied DECtape was then added to by the user, and thus was storagefor personal programs and data. A second DECtape was used as a scratch tape by the assembler and the Fortran compiler.[14]

RSX-15

RSX-15 was released by DEC in 1971.[15] The main architect for RSX-15 (later renamed XVM/RSX) was Dennis "Dan" Brevik.[16] [17]

Once XVM/RSX was released, DEC facilitated that "a PDP-15 can be field-upgraded to XVM" but it required "the addition of the XM15 memory processor."

The RSX-11 operating system began as a port of RSX-15 to the PDP-11, although it later diverged significantly in terms of design and functionality.[18]

Origin of the RSX-15 name

Commenting on the RSX acronym, Brevik says:[19]

XVM/RSX

Later versions of the PDP-15 could run a real-time multi-user OS called XVM/RSX, an outgrowth of RSX-15.[20] [6] The XVM upgrade to RSX was multi-user, and enabled up to six concurrent teletype-based users.[21] XVM Support for the PDP-15/76 included using an RK05 disk drive.[22]

non-DEC

The MUMPS operating system, which was originally developed in 1966,[23] was developed on the PDP-7 outside DEC. It is also available for the PDP-15.

Application software

DEC provided mathematical, scientific and commercial software application tools.[7] [24]

See also

External links

Notes and References

  1. Web site: Computer Engineering . C. Gordon Bell . J. Craig Mudge . John E. McNamara . by 1977, 790 machines had been shipped - more than the total of all other DEC 18-bit machines..
  2. Book: DOS-15 System Manual .
  3. Book: DIGITAL EQUIPMENT CORPORATION - Nineteen Fifty-Seven To The Present. 1975 . Digital Equipment Corporation.
  4. Web site: The Early Architectures of DEC.
  5. Web site: PDP-15 FORTRAN IV Operating Environment.
  6. Web site: PDP-15 . BitSavers.
  7. Book: pdp15 pdp15/76 system reference manual . October 1973 . Digital Equipment Corporation.
  8. Book: A History of Modern Computing . 209. 978-0262532037. Paul E. Ceruzzi . 2012. MIT Press.
  9. Book: 2014. Computer Engineering: A DEC View of Hardware Systems Design. 978-1483221106. Bell . C. Gordon . Mudge . J. Craig . McNamara . John E.. Digital Press.
  10. Web site: PDP Lineage.
  11. Web site: CS3220 Project 1: DEC PDP-15.
  12. A PDP-15/50, described then as "expensive to maintain," was still running in 1982. Web site: Annual Report 1982 . to be taken out of operation at the end of 1982..
  13. Book: Computer Engineering: A DEC View of Hardware Systems Design . C. Gordon . Bell . J. Craig . Mudge . John E. . McNamara . Digital Press . May 12, 2014 . 162 .
  14. Web site: Technical Notes on DECsys . Bob Supnik . 19 June 2006.
  15. Web site: RSX-15 Real Time Executive reference manual . Digital Equipment Corporation . 1971 . 4 December 2017.
  16. Web site: General FAQ. www.miim.com. 2019-12-10.
  17. Web site: Reference letter for Dan Brevick . Lacroute . Bernard . 3 May 1982 . English . https://web.archive.org/web/20050118011030/http://www.demillar.com/RSX/lacroute.pdf . 18 January 2005 . dead . 4 December 2017.
  18. Cutler. Dave. Dave Cutler. Grant Saviers. Dave Cutler Oral History. https://ghostarchive.org/varchive/youtube/20211213/29RkHH-psrY . 2021-12-13 . live. Computer History Museum. 2016-02-25. youtube.com. 2021-02-26.
  19. Web site: RSX FAQ, General . 4 December 2017.
  20. Web site: BitSavers . DEC-15-XSRMA-A-D_UC15refMan.pdf.
  21. News: . August 30, 1976 . 37. Mutliuser PDP-15 XVM/RSX.
  22. Web site: XVM upgrades.
  23. Web site: Unearthing The PDP-15's Operating Systems . Bob Supnik.
  24. "Commercial Subroutine Package (CSP) ... compatible with the IBM 1130 commercial subroutine package."

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