Cyber205 was RE: Ebay horror ...

From: Douglas Quebbeman <>
Date: Tue Jun 12 18:45:47 2001

> S.C. a CDC founder? fantastic!
> 205/LSI after the Cray-1? check.
> Ok, continuing after a "real work"* break.
> What made the 205 get singled out for so
> long as an a**kicker? True multiprocessing?
> Did it beat the Cray-1?

Overview of Platform
Vector Architecture.

Compute Hardware
Architecture: ECL/LSI logic (168 gates/chip) Sequential and parallel
processing on single bits, 8-bit bytes and 32- or 64-bit floating-point
operands 20-nsec cycle time Scalar Unit Segmented functional units 64-word
instruction stack 256 word high-speed register file Vector Unit 1, 2, or 4
segmented vector pipelines memory-to-memory data streaming maximum vector
length of 65,536 words gather/scatter instructions up to 800 million 32-bit
floating-point operations/second

Interconnect / Communications System

Memory System
  MOS semiconductor memory
  Memory size: 1, 2, 4, 8 or 16 million 64-bit words
  Virtual memory accessing mechanism with multiple, concurrently
 usable page sizes
  SECDED on each 32-bit half word
  48-bit address (address space of 4 trillion words per user)
  80 nsec memory bank cycle time
  Memory bandwidth: 25.6 or 51.2 Gigabits/second

Benchmarks / Compute and data transfer performance
 Linked triad performance on long vectors approaches asymptotic
  speed of machine.
 Performance can be severely degraded at short vector lengths
  (that is, the typical $n _ {1/2}$ is around 100), and if
  vector is not held contiguously. For this reason most
  tuned software employs long, contiguously held vectors.

Operating System Software and Environment
 Virtual operating system
 Batch and interactive access
 FORTRAN compiler
  ANSI 77 with vector extensions
  32-bit half-precision data type
  Special calls to machine instructions
  Automatic vectorization
  Scalar optimization utilizing large register file

  Interactive symbolic debugger
  Source code maintenance
  Object code maintenance

Networkability/ I/O System / Integrability / Reliability / Scalability
  Eight I/O ports, 32-bits in width, expandable to 16
  200 Mbits/second for each port
  Maximum I/O port bandwidth of 3200 Mbits/sec

  Cooling: freon
  Dimensions: floor area (four pipe model) 23 ft x 19 ft
   footprint (with I/O system) 105 sq ft

Notable Applications / Customers / Market Sectors

Overall Comments

Received on Tue Jun 12 2001 - 18:45:47 BST

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