Microvax computer family

Digital Equipment Corporation (DEC) introduced the VAX (Virtual Address eXtension) method in the MicroVax family of microprocessors, implementing the " Instruction Set Architecture" for the first time. The low-end MicroVAX I model, released in 1984, was followed in 1985 by the higher-end MicroVAX II (pictured) , described below.

Category:

Small (mini) machine

Technology:

Mixed circuit

Origin:

import

Manufacturer:

Digital Equipment Corporation (DEC)

Use

Operating time:

Release: 1985

Typical applications:

Large-scale batch data processing

Year:

In the simplest configuration 5000 USD

Structure

Central unit

The computer was built from TTL circuits, except for the microprocessors.

controller: KA630-AA main module, including MicroVax 78032 microprocessor, real-time clock; clock frequency 5 MHz
main memory: 1 -2 -4 – 16 MB DRAM (depending on MA630 memory expansion module — AA, BA, BB, CA — respectively)
calculator: fixed-point and floating-point ALU (MicroVax 78132)
channel: Q22 bus system (3.3 MBps) and interfaces for connecting external devices and expansions

Periphery

backups:
- 68 MB fixed hard drive
- 128 MB magnetic tape
external devices:
- console monitor
- keyboard
- line printer

Operation

The OpenVMS operating system virtually mapped external devices in the main storage and handled data traffic with each through its own storage domain.

Program set

General programs

operating system: OpenVMS: multi-user, multi-processor, virtual storage management system, basically for time-sharing, batch processing, but also worked as a real-time system with appropriate priority settings

Detailed description: OpenVMS (English)

compilers:
- Fortran
- DCL command language, for easier handling of certain data types (strings, integers, bit arrays and logical variables), even by statement (interpreter), and for querying the system status
utilities: graphical user interface (GUI), integrated with the operating system

Custom programs

n.a.

Historical curiosities

The MicroVAX II was released in three configurations:

The KA620, a single-board version, was designed for automated testing of assembly and manufacturing jobs, with a VAXELN operating system and 1 MB of main memory.
It functioned as a fault-tolerant system called Mira, with two microprocessors (one active and one spare); in the event of a failure, the system automatically switched to the spare; an industrial version of this was marketed in a more robust housing as the VAX 630
A desktop version was also made called 630QE

Resources

Brief description: MicroVax II (English)

Detailed description of MicroVax models: Microvaxes (English)

Created: 2016.06.30. 18:57
Last modified: 2025.02.19. 16:56

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