PA-RISC information - since 1999

Apollo PRISM Processor

Overview

Apollo PRISM was a RISC processor with VLIW (Very Long Instruction Word) design, developed by Apollo Computer Inc. and released in 1988. It was implemented in CMOS with eleven VLSI chips at 20 MHz clock and able to combine three instructions into one. For the time, PRISM was billed as one of the fastest RISC processors, able to support up two four CPUs in a single system (SMP).

PRISMs processors were used in Apollo's own Domain 10000 (DN10000) computers, with a PRISM II processor already being planned and designed. After the acquisition by HP in 1989, Apollo products were integrated into the HP line up, but the PRISM II processor dropped. In 1989 HP was still communicating an upgraded PRISM processor (DN10000TX upgrade) with streamlined architecture, higher clock, double computing power (from 22 to 44 MIPS), increased caches to be fabbed by HP’s Colorado ASIC factory in 1991 in 1.0µ.

PRISM was sometimes codenamed A88K (or a88k), not to be confused with the Motorola M88K 88000 RISC processors. Parts of the PRISM architecture were later reused in PA-RISC, specifically technologies for HP’s own floating-point units (FPUs).

PRISM Details

Used in

PRISM2 (DN10000TX)

Benchmarks

Based on Dhrystone and MIPS archives; * - unsure
System Processor SPEC89 MIPS
Apollo DN10000 Apollo PRISM 18 MHz 19 22
Apollo DN10000 4 Apollo PRISM 18 MHz 60-100*
Apollo DN10000-TX Apollo PRISM2 36 MHz 44*

Comparison to SPEC benchmark data from other contemporary Unix computers:

Based on Dhrystone archives
System Processor SPEC89 MIPS
HP 9000 705 PA-7000 35 MHz 34 49
Intel i486DX2 66 MHz 25 31
Sun SPARCstation 2 SPARC 40MHz 25 28
DECstation 5000/200 MIPS R3000 25MHz 23 22
DECstation 3100 MIPS R2000 16MHz 11.8 15.1
HP 9000 425e Motorola M68040 25MHz 10.3 18*
HP 9000 834 NS-1 PA-RISC 30 MHz 9.5 14
Intel i386 33MHz 4.3 8
DEC VAX 11/780 KA780 3.4MHz 1.0 0.9

Documentation

  1. The DN 10000TX: a new high-performance PRISM processor, COMPCON Spring ’91 Digest of Papers, 1991
  2. APOLLO COMPUTER LAUNCHES ITS 64-BIT PRISM RISC MACHINE, Tech Monitor archive, February 29, 1988
  3. WHY APOLLO COMPUTER RECKONS IT HAS OUTDONE SUN IN THE RISC STAKES, Tech Monitor archive, March 14, 1988
  4. Apollo CPUs, Apollo/DOMAIN Computers at zepa.net, 2003 (archive.org from 20030201)
  5. HP unveils plan for new PRISM CPU, Hewlett Packard, Press Release October 1989 1000bit.it

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