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"…sequential computers are approaching a fundamental physical

limit on their potential power. Such a limit is the speed of light…"

Alpha Data ADC-HPCI  PCI bus interface development board
for IEEE 1355 DS-DE links


BAR 0 Operation registers of S5933 PCI chip, reserved
BAR 1 64 words of 32 bits I/O space, C101 registers for Link 0
BAR 2 64 words of 32 bits I/O space, C101 registers for Link 1
BAR 3 I/O space, writing generates hard reset to both C101s
BAR 4 not used
BAR 5 not available

Software provided includes C routines for determining the base address registers set up by the BIOS, and for transmitting and receiving virtual channel packets.
EMC features on all boards include AT&T buffers with minimised output skew, common mode chokes on outputs, use of Harlink bracket and EMC gasket for 1355 connectors, and split 5V plane to minimise coupling to link signals. A particular EMC feature is the use of a spread-spectrum link clock to reduce emissions from the cables.




The ADC-HPCI provides a simple interface between the PCI bus and two 1355 links. The links are buffered in accordance with the DS-DE specification of IEEE 1355 (and also to be ISO/IEC 14575CD). 1355 links provide an exceptionally light-weight Virtual Channel protocol for serial communication between processors, between I/O systems, or between I/O systems and processors. The standard PCI "large card" form-factor allows PCs, PowerPCs, or Alphas to use 1355 links.

Processor DEC Alpha 21066 fully-pipelined 64-bit RISC architecture
  • 233MHz (466 mips, 233MFLOPS) using dual instruction issue
  • IEEE and VAX-compatible floating point
  • High bandwidth 64-bit memory controller
  • Memory management
  • 8k on-chip data and instruction caches
  • Secondary cache controller
  • Asynchronous PCI I/O controller
  • Intel compatible PCI bus


  • Running at 25MHz
  • Supporting Virtual Channel Routing (VCR)
  • Includes 4 DS links based on the IEEE P1355 standard
Memory DEC Alpha
  • 8MB to 32MB of 70ns DRAM
  • 256K to 1MB 15ns external cache SRAM


  • 128KB of local SRAM
Host interface Connected to an HTRAM carrier board
Software 3L Parallel C/AXP compiler with parallel network support
  • (including DEC GEM compiler).
  • IPLib and fast maths libraries

INMOS T9000 toolset for the T9000

Warranty 12 months from date of invoice


User Manual & Support Software

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