NCR/32
General information
Marketed byNCR Corporation
Physical specifications
Cores
  • 1

The NCR/32 VLSI Processor family was a 32-bit microprocessor architecture and chipset developed by NCR Corporation in the early 1980s. Generally used in minicomputer systems, it was noteworthy for being externally microprogrammable.[1][2]

History

NCR announced the release of its NCR/32 architecture, comprising an initial four-chip set, in the third quarter of 1982.[3] The Central Processor Chip included an external microcode bus that let a designer create custom instructions for specific applications.

This feature was used to develop microcode that allowed the NCR/32 to emulate NCR's earlier mainframe computers, or an IBM System/370.[4]:1–5

The design also enabled high-level languages, such as Prolog and polyFORTH, to be executed directly from custom instructions in the external microcontrol store.[5][6]

Both the NCR/32 processor and some products that used it have been called reduced instruction set computer (RISC) systems, although the description has been debated.[7][8][9] The NCR/32 has also been described as a bit-slice architecture.[10][11][12]

NCR used the processor architecture in certain models of their own computer systems, communications peripherals, and at least one board-level product.

Some of the designers of the NCR/32 left NCR for a new company, Celerity Computing, which used the NCR/32 in its own minicomputer designs, running a version of the University of California at Berkeley's Unix Release 4.2.[11][13]

Chipset

The chipset for the NCR/32 family includes the following devices:

  • NCR/32-000 Central Processor Chip (CPC)
  • NCR/32-010 Address Translation Chip (ATC)
  • NCR/32-020 Extended Arithmetic Chip (EAC)
  • NCR/32-500 System Interface Controller (SIC)
  • NCR/32-580 System Interface Transmitter (SIT)
  • NCR/32-590 System Interface Receiver (SIR)

Features

The NCR/32-000 CPC was the cornerstone of the architecture; all of the other devices were optional. The CPC consists of 40,000 transistors, and was originally fabricated in a 3 micron NMOS process. The device supports two levels of microcode: vertical microcode, stored in an external 128K-byte Instruction Storage Unit (ISU), and horizontal microcode, stored in an internal Read-only memory (ROM) encoding 179 operations in a set of 95-bit wide words. The CPC accesses the ISU over a 16-bit wide Instruction Storage Unit Bus (ISUBUS), feeding a 3-stage microinstruction pipeline. Internally, the CPC has a 32-bit wide Arithmetic Logic Unit (ALU), and 16 32-bit general purpose registers. The processor can address up to 4 GB of direct virtual memory, and 16 MB of direct real memory over a 32-bit wide Processor Memory Bus (PMBUS). The base clock frequency of the CPC is 13.3 MHz. With its two-phase, non-overlapping clock, each machine cycle takes two "ticks", yielding a cycle time of 150 nanoseconds (nS). 90% of the CPC's microinstructions complete in a single cycle.[1][4][14]

A revised version of the CPC was released later, with device geometry reduced from 3 to 2 microns[15] Cycle time on higher-performance NCR 10000 systems was down to 110 nS.[16]

The NCR/32-010 ATC provides advanced memory management services such as address translation, access protection, memory-refresh control, and error-checking and correction (ECC). It contains sixteen translation registers which handle mapping of 32-bit or 24-bit virtual addresses into 24-bit physical addresses, with page sizes of 1K, 2K, or 4K bytes.[4][14]

The NCR/32-020 EAC accelerates the execution of arithmetic operations, performing IBM-compatible single- and double-precision binary and floating-point arithmetic, packed and unpacked decimal storage, and format conversions.[14]

The NCR/32-500 SIC interfaces the PMBUS to slower peripherals and other systems. The NCR/32-580 SIT and NCR/32-590 SIR perform perform data format conversions. The SIC/SIT/SIR combination can operate in one of two modes: Data Link Control or Local Area Network.[14][1]

Applications

References

  1. 1 2 3 NCR Microelectronics Short-Form Catalog—1985 (PDF). Dayton, Ohio, U.S.A.: NCR Corporation. 1985.
  2. Bond, John (1 June 1984). "Architectural Advances Spur 32-Bit Micros". Computer Design. pp. 125–136.
  3. Hannum, David L. (December 1983). "microREVIEW". IEEE Micro. Institute of Electrical and Electronics Engineers. pp. 66–68.
  4. 1 2 3 NCR/32 General Information (PDF). Dayton, Ohio, U.S.A.: NCR Corporation. 1984.
  5. Fagin, Barry; Patt, Yale; Srini, Vason; Despain, Alvin (December 1985). "Compiling Prolog Into Microcode: A Case Study Using the NCR/32-000". Proceedings of the 18th annual workshop on Microprogramming. MICRO-18. Association for Computing Machinery. pp. 79–88. doi:10.1145/18927.18914.
  6. McBride, Michael L. (January 1984). "Technical Notes — polyFORTH on the NCR/32" (PDF). The Journal of Forth Application and Research. 2 (1): 77–84.
  7. Masters, Clark (18 November 2021). "Oral History of Clark Masters" (PDF). Computer History Museum (Interview). Interviewed by Uday Kapoor. Escondido, California.
  8. 1 2 MacNicol, Gregory (March 1985). "A Risky New Architecture For The Future?" (PDF). Digital Design. pp. 92–98.
  9. Kern, Dr. Ralf (January–February 1989). "Die Mikroprozessor-Story" [The Microprocessor Story] (PDF). Prisma (in German). No. 1. Computerclub Deutschland e.V. pp. 7–12.
  10. 1 2 3 "NCR Moves Mid-Range System 10000 Up-Market with Model 85". techmonitor.ai. 2 May 1990.
  11. 1 2 3 "Celerity Shuts Up Shop, Shedding 70% of its Workforce". techmonitor.ai. 7 February 1988.
  12. "FPS Japan to Capitalise on its Parent's Acquisition". 27 Sep 1988. Archived from the original on 2021-04-19. Retrieved 2023-08-06.
  13. "Systems & Peripherals — Celerity: 32-bit engineering unit faster than VAX-11". Computerworld. 1984-09-17. p. 69.
  14. 1 2 3 4 Mateosian, Richard (January 1984). "1984, the Year of the 32-bit Microprocessor" (PDF). Byte. Vol. 9, no. 1. pp. 134–150.
  15. 1 2 3 4 Boucher, Henri. Catalogue informatique de Henri Boucher (PDF). Vol. C.
  16. "System 10000 Model 65, Model 75 and Model 85". NCR Products and Systems Pocket Digest (PDF). NCR Corporation. January 1991. pp. 51–55.
  17. "Modell 9300 bietet eine maximale Hauptspeicherkapazität von 4 MB: NCR-Computer mit neuem 32-Bit-Chip" [Model 9300 offers a maximum memory capacity of 4 MB: NCR computer with new 32-bit chip]. www.computerwoche.de (in German). 1 April 1983.
  18. "NCR Marries Its Tower Unix Boxes With Fault-Tolerant 9800". techmonitor.ai. 16 September 1987.
  19. Allison, Andrew (May 1987). "Multiprocessors Boost System Power" (PDF). Mini-Micro Systems. Vol. XX, no. 5. Cahners. pp. 105–117.
  20. "New Products — NCR claims seamless PC integration and transparent networking for new System 10000" (PDF). Computer. The Institute of Electrical and Electronics Engineers. May 1988. p. 94.
  21. Bozman, Jean S. (7 March 1988). "NCR to show next mini line". Computerworld. Vol. XXII, no. 10. p. 1.
  22. "NCR Integrates Mid-Range NCR 10000 With MS-DOS Computing". techmonitor.ai. 14 March 1988.
  23. "Systems & Peripherals — NCR adds 32-bit board-level processor". Computerworld. Vol. XVII, no. 50. 10 December 1984. p. 105.
  24. Dix, John (4 March 1985). "NCR Comten rolls out processor, tools". Computerworld. Vol. XIX, no. 9. pp. 77, 78.
  25. "Microbytes — Nanobytes" (PDF). Byte. April 1984. p. 10.
  26. "Honeywell-NCR". The New York Times. 8 February 1984. p. D-4.
  27. "Company Profiles — 15 Honeywell Inc" (PDF). Datamation. 1 June 1985. p. 70.

Further reading

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