VAX 8000

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VAX 8000

The VAX 8000 is a family of minicomputers developed and manufactured by Digital Equipment Corporation

Digital Equipment Corporation

Digital Equipment Corporation was a pioneering United States company in the computer industry. It is often referred to within the computing industry as DEC ....
(DEC) using processors implementing the VAX

VAX

VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs....
instruction set architecture (ISA).

VAX 8600, code-named "Venus", was introduced in October 1984.

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Encyclopedia

The VAX 8000 is a family of minicomputers developed and manufactured by Digital Equipment Corporation

Digital Equipment Corporation

VAX

VAX 8600

The VAX 8600, code-named "Venus", was introduced in October 1984. It was originally intended to be named "VAX-11/790", but was renamed before launch. It has an ECL

Emitter coupled logic

In electronics, emitter-coupled logic, or ECL, is a logic family in which current is steered through Bipolar junction transistors to implement logic functions....
gate array

Gate array

A gate array or uncommitted logic array is an approach to the design and manufacture of application-specific integrated circuits . A gate array circuit is a prefabricated silicon chip circuit with no particular function in which transistors, standard NAND or NOR logic gates, and other active devices are placed at regular predefined pos...
-based CPU.

VAX 8650

The VAX 8650, code-named "Morningstar", introduced on 4 December 1985. It was a faster version of the VAX 8600 and was originally intended to be named "VAX-11/795", but was renamed before launch. It was the last VAX to be 100% compatible with the VAX-11/780

VAX-11

The VAX-11 is a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture ....
and VAX-11/785

VAX-11

The VAX-11 is a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture ....
and the last VAX to have a PDP-11

PDP-11

The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s. Though not explicitly conceived as successor to DEC's PDP-8 computer in the Programmed Data Processor series of computers , the PDP-11 replaced the PDP-8 in many Real-time computing....
compatibility mode. It was also the last model to use SBI

Synchronous Backplane Interconnect

The Synchronous Backplane Interconnect was the internal processor-memory bus used by early VAX computers manufactured by the Digital Equipment Corporation of Maynard, Massachusetts....
backplane also used by VAX-11/78x models.

VAX 8200

The VAX 8200, code named "Scorpio", was introduced on 29 January 1986. It uses the KA820 CPU module containing a V-11

V-11

The V-11, code-named "Scorpio", is a microprocessor chip set implementation of the VAX instruction set architecture developed and Semiconductor device fabrication by Digital Equipment Corporation ....
processor operating at 5 MHz (200 ns cycle) and supports a maximum of 128 MB of ECC memory. It has one VAXBI bus and support for an optional Unibus

Unibus

The Unibus was the earliest of several Computer bus technologies used with PDP-11 and early VAX systems manufactured by the Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts....
.

VAX 8250

The VAX 8250 was a faster VAX 8200 introduced in early March 1987. It uses the KA825 CPU module containing a V-11 processor operating at 6.25 MHz (160 ns cycle).

VAX 8300

The VAX 8300 was a dual-processor variant of the VAX 8200 introduced on 29 January 1986.

VAX 8350

The VAX 8350 was a faster VAX 8300 introduced in early March 1987. It uses the KA825 CPU module containing a V-11 processor operating at 6.25 MHz (160 ns cycle).

VAX 8800 Family

Models

VAX 8800

Code-named "Nautilus", is the high-end model in the VAX 8800 family. It featured two CPUs and two VAXBI buses as standard. Development of the VAX 8800 began in August-November 1982 and it was introduced on 29 January 1986. When "Polarstar" systems were introduced, the VAX 8800 was renamed to VAX 8820N.

VAX 8700

The VAX 8700, code-named "Nautilus", was introduced in early August 1986. It is similar to the VAX 8800 but with only one CPU and VAXBI bus. It was upgradable to a VAX 8800.

VAX 8550

The VAX 8550, code-named "Skipjack", was introduced in early August 1986. It is similar to the VAX 8700, but was not upgradable to the VAX 8800.

VAX 8500

The VAX 8500, code-named "Flounder", is a lower-performance variant of the VAX 8550, with microcode used to insert nop

NOP

In computer science NOP or NOOP is an assembly language instruction, sequence of programming language statements, or protocol command that effectively does nothing at all....
s during operation to limit performance.

VAX 8530

The VAX 8530, code-named "Skipjack", is an upgraded VAX 8500 with the nops removed for improved performance introduced in early March 1987.

Polarstar

Polarstar is a variant of Nautilus with one to four processors and an updated console processor. Models included the:

VAX 8810 - A single processor system
VAX 8820 - A two processor system

VAX 8842 - A cluster of two VAX 8820 systems

VAX 8830 - A three processor system
VAX 8840 - A four processor system

VAX 8974 - Introduced on 20 January 1987, it was a cluster of four VAX 8700 systems
VAX 8978 - introduced on 20 January 1987, it was a cluster of eight VAX 8700 systems

Description

The VAX 8800 family is based on the NMI bus, which connected the CPU, memory controller and I/O adapters. The NMI bus is a 32-bit synchronous bus with a usable bandwidth of 64 MB/s.

The VAX 8800 family central processing unit

Central processing unit

A central processing unit is an electronic circuit that can execute computer programs. This broad definition can easily be applied to many early computers that existed long before the term "CPU" ever came into widespread usage....
(CPU) operates at 22.22 MHz (45 ns cycle time) and is implemented with discrete emitter-coupled logic (ECL) devices spread over eight modules. The majority of the ECL devices are macrocell array

Macrocell array

A macrocell array is an approach to the design and manufacture of Application-specific integrated circuits. Essentially, it is a small step up from the otherwise similar gate array, but rather than being a prefabricated array of simple logic gates, the macrocell array is a prefabricated array of higher-level logic functions such as Flip-flop...
s with 1,200 logic gate

Logic gate

A logic gate performs a logical operation on one or more logic inputs and produces a single logic output. The logic normally performed is Boolean logic and is most commonly found in digital circuits....
s, while the general-purpose registers and floating-point units are custom logic devices developed by Digital. The CPU has 64 KB of cache implemented with 10 ns and 15 ns ECL random access memory devices.

The VAX 8800 and 8700 supported one to eight memory array modules, the VAX 8550 and 8500 one to five. The memory array modules are installed in a dedicated backplane separate from the NMI backplane. The VAX 8800 and VAX 8700 supported 4 to 32 MB of memory, the VAX 8500 and VAX 8550 4 to 20 MB, using the 4 MB memory module. When the 16 MB memory module was introduced, the memory capacity of the VAX 8800 and 8700 was increased to 128 MB, and that of the VAX 8550 and 8500 to 80 MB.

The VAX 8000 uses the VAXBI for input/output. The VAX 8800 can support four VAXBI buses, with each bus supporting up to 16 I/O devices. The VAXBI bus is interfaced to the NMI bus by a NBI adapter containing a chip implementing the VAXBI bus protocol. The NBI adapter handles all CPU references and direct memory access

Direct memory access

Direct memory access is a feature of modern computers and microprocessors that allows certain hardware subsystems within the computer to access system Computer storage for reading and/or writing independently of the central processing unit....
(DMA) transactions to and from the I/O devices. The adapter operates at 5 MHz and asynchronously to the CPU as it generates it own clock signal

Clock signal

In electronics and especially Synchronous logic digital circuits, a clock signal is a Signalling used to coordinate the actions of two or more Electronic circuit....
. The NBI adapter consisted of two modules, the NBIA and NBIB. The NBIA is the NMI side of the adapter, and the NBIB, the VAXBI side.