VAX 9000 computer family

n.a.

A representative copy is kept by the Computer History Museum (Mountain View, California, USA)

Structure

Central unit

Word-organized machine: 32 bpW

• actuators: one in each
  • scalar processor: 13 Multi-Chip Units (MCUs), in which the logic circuits were distributed in multiple emitter-coupled ( ECL ) cell arrays (macrocell arrays) (total size 610 mm ² ); and
  • optionally vector processor (V-box), which is built up of 6 subunits:
    • register unit, including 16 64-element, 72-bit (64 data + 8 parity bits) vector registers, 3 write and 5 read interfaces (ports)
    • adding machine
    • multiplication table
    • mask unit
    • address management unit
    • local control unit

The sub-units were connected to each other and to the main warehouse by a crossbar rail system.

• main memory: up to 512 MB, electronic (ECL) memory
• calculator: built into vector processors
• channel: input/output devices were connected to the central machine via a configuration-independent, synchronous, 32-bit address and data bus system (such as VAXBI (VAX Bus Interconnect))

Periphery
Two SBI (Synchronous Backplane Interconnect) bus systems were used to connect the storage devices and external devices:

• 1 – 4 Unibus for slow devices (3 optional)
• optionally 1-4 Massbus for back-up storage

External devices were managed directly by the central control unit

Operation

The SID (Synthesis of Integral Design) program built the specific logic architecture operating on the assembly line principle for about 93% of scalar and vector processors.

SID was an Artificial Intelligence (AI)-based, learning-rules system that, in addition to designing logic circuits, also defined their connections, distributed loads on internal networks, and generated the parameters necessary for running application programs. During its operation, it expanded its own rule system as needed, with up to 384,000 low-level rules (in about 3 hours of runtime)

The maximum operation speed of vector processors was 125 Mflops

Program set

• operating system:
  • VAX/VMS
  • Ultrix (Digital Unix version)
• compilers: na

Historical curiosities

The VAX 9000 models were the last large computers not to be microprocessor-controlled. The machines were originally designed to be water-cooled due to the high heat generation of the numerous circuits, but the oversized cabinets caused shipping difficulties, so they were redesigned to be air-cooled.

The circuits generated by SID for the machines were completed 2 years ahead of schedule, as their operating rules were often better than those designed by hand during the design process. (For example, the SID-designed 64-bit adder had an average of 100 times fewer errors per logic gate, which could be corrected to build error-free circuits.)

Although the SID was protected by 15 patents, DEC no longer used it after the VAX 9000 series. There was no working copy in Hungary.

Resources

Description of the models and their operation: VAX 9000 (English)