The MicroVAX is a discontinued family of low-cost
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s developed and manufactured by
Digital Equipment Corporation
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president unti ...
(DEC). The first model, the MicroVAX I, was introduced in 1983.
[(announced October 1983) ] They used processors that implemented the
VAX instruction set architecture
In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ...
(ISA) and were succeeded by the
VAX 4000 The VAX 4000 is a discontinued family of low-end minicomputers developed and manufactured by Digital Equipment Corporation (later Compaq) using microprocessors implementing the VAX instruction set architecture (ISA). The VAX 4000 succeeded the Mi ...
. Many members of the MicroVAX family had corresponding
VAXstation
The VAXstation is a discontinued family of workstation computers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture. VAXstation systems were typically shipped with eit ...
variants, which primarily differ by the addition of graphics hardware.
The MicroVAX family supports Digital's
VMS #REDIRECT VMS
{{redirect category shell, {{R from other capitalisation{{R from ambiguous page ...
and
ULTRIX operating systems. Prior to VMS V5.0, MicroVAX hardware required a dedicated version of VMS named
MicroVMS.
MicroVAX I
The MicroVAX I, code named "''Seahorse''", introduced in October 1984, was one of DEC's first VAX computers to use
very-large-scale integration (VLSI) technology. The KA610 CPU module (also known as the KD32) contained two custom chips which implemented the
ALU
ALU, Alu or alu may refer to:
Computing and science
;Computing
*Arithmetic logic unit, a digital electronic circuit
;Biology
* Alu sequence, a type of short stretch of DNA
*'' Arthrobacter luteus'', a bacterium
Organizations
* Abraham Lincoln ...
and
FPU FPU may stand for:
Universities
* Florida Polytechnic University, in Lakeland, Florida, United States
* Franklin Pierce University, in New Hampshire, United States
* Fresno Pacific University, in California, United States
* Fukui Prefectural Univ ...
while
TTL chips were used for everything else. Two variants of the floating point chips were supported, with the chips differing by the type of floating point instructions supported, F and G, or F and D. The system was implemented on two quad-height
Q-bus cards - a Data Path Module (DAP) and Memory Controller (MCT).
The MicroVAX I used Q-bus memory cards, which limited the maximum memory to 4MiB.
The performance of the MicroVAX I was rated at 0.3
VUPs, equivalent to the earlier
VAX-11/730.
MicroVAX II
The MicroVAX II, code named "''Mayflower''", was a mid-range MicroVAX introduced in May 1985 and shipped shortly thereafter.
It ran
VAX/VMS or, alternatively,
ULTRIX, the DEC native Unix operating system. At least one non-DEC operating system was available,
BSD Unix from
MtXinu.
It used the KA630-AA CPU module, a quad-height
Q22-Bus module, which featured a
MicroVAX 78032 microprocessor and a
MicroVAX 78132 floating-point coprocessor operating at 5 MHz (200 ns cycle time). Two
gate array
A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) accord ...
s on the module implemented the external interface for the microprocessor, Q22-bus interface and the scatter-gather map for DMA transfers over the Q22-Bus. The module also contained 1 MB of memory, an interval timer, two ROMs for the boot and diagnostic facility, a DZ console serial line unit and a time-of-year clock. A 50-pin connector for a ribbon cable near the top left corner of the module provided the means by which more memory was added to the system.
The MicroVAX II supported 1 to 16 MB of memory through zero, one or two memory expansion modules. The MS630 memory expansion module was used for expanding memory capacity. Four variants of the MS630 existed: the 1 MB MS630-AA, 2 MB MS630-BA, 4 MB MS630-BB and the 8MB MS630-CA. The MS630-AA was a dual-height module, whereas the MS630-BA, MS630-BB and MS630-CA were quad-height modules. These modules used 256 Kb DRAMs and were protected by byte-parity, with the parity logic located on the module. The modules connected to the CPU module via the backplane through the C and D rows and a 50-conductor ribbon cable. The backplane served as the address bus and the ribbon cable as the data bus.
The MicroVAX II came in three models of enclosure:
* BA23
* BA123
* 630QE - A deskside enclosure.
KA620
KA620 referred to a
single-board MicroVAX II designed for automatic test equipment and manufacturing applications which only ran DEC's real-time
VAXELN operating system. A KA620 with 1 MB of memory bundled with the VAXELN Run-Time Package 2.3 was priced at US$5,000.
Mira
Mira referred to a fault-tolerant configuration of the MicroVAX II developed by DEC's European Centre for Special Systems located in
Annecy in France. The system consisted of two
MicroVAX 78032 microprocessors, an active and standby microprocessor in a single box, connected by Ethernet and controlled by a software switch. When a fault was detected in the active microprocessor, the workload was switched over to the standby microprocessor.
[Computergram (21 May 1987)]
"DEC France Does Fault-Tolerant MicroVAX II Configuration"
''Computer Business Review''.
Industrial VAX 630
A MicroVAX II in BA213 enclosure.
MicroVAX III
BA23- or BA123-enclosure MicroVAX upgraded with KA650 CPU module containing a
CVAX chip set.
MicroVAX III+
BA23- or BA123-enclosure MicroVAX upgraded with KA655 CPU module.
VAX 4
BA23- or BA123-enclosure MicroVAX upgraded with KA660 CPU module.
MicroVAX 2000
The MicroVAX 2000, code named "''TeamMate''", was a low-cost MicroVAX introduced on 10 February 1987.
[Computergram (11 February 1987)]
"DEC Puts Old Wine Into New Bottles With MicroVAX 2000"
''Computer Business Review''. In January 1987, the MicroVAX 2000 was the first VAX system targeted at both universities and VAX programmers who wanted to work from remote locations.
The MicroVAX 2000 used the same microprocessor and floating-point coprocessor as the MicroVAX II, but was feature reduced in order to lower the cost. Limitations were a reduced maximum memory capacity, 14 MB versus 16 MB in MicroVAX II systems and the lack of
Q-Bus or any expansion bus. The system could have a
Shugart-based harddrive with
ST412 interface and
MFM encoding and had a built in 5.25-inch floppy drive (named RX33 in DEC jargon) for software distribution and backup. Supported operating systems were VMS and ULTRIX.
It was packaged in a desktop form factor.
MicroVAX 3100 Series
The MicroVAX 3100 Series was introduced in 1987. These systems were all packaged in desktop enclosures.
;MicroVAX 3100 Model 10
: ''Teammate II''
: KA41-A,
CVAX, 11.11 MHz (90 ns)
;MicroVAX 3100 Model 10e
: ''Teammate II''
: KA41-D,
CVAX+, 16.67 MHz (60 ns)
: 32 MB of memory maximum.
;MicroVAX 3100 Model 20
: ''Teammate II''
: KA41-A, CVAX, 11.11 MHz (90 ns)
: A Model 10 in larger enclosure.
;MicroVAX 3100 Model 20e
: ''Teammate II''
: KA41-D, CVAX+, 16.67 MHz (60 ns)
: A Model 10e in larger enclosure.
;MicroVAX 3100 Model 30
: ''Waverley/S''
: Entry-level model, developed in Ayr, Scotland
[Computergram (29 January 1992)]
"DEC Launches Three MicroVAXes Designed And Made In Ayr"
''Computer Business Review''.
: Introduced: 12 October 1993
: KA45,
SOC, 25 MHz (40 ns)
: 32 MB of memory maximum.
;MicroVAX 3100 Model 40
: ''Waverley/S''
: Entry-level model, developed in Ayr, Scotland
: Introduced: 12 October 1993
: KA45, SOC, 25 MHz (40 ns)
: 8 to 32 MB of memory
: A Model 30 in larger enclosure.
;MicroVAX 3100 Model 80
: ''Waverley/M''
: Entry-level model, developed in Ayr, Scotland
: Introduced: 12 October 1993
: KA47,
Mariah, 50 MHz (20 ns), 256 KB external cache
: 72 MB of memory maximum.
;MicroVAX 3100 Model 85
: ''Waverley/M+''
: Introduced: August 1994
: KA55,
NVAX, 62.5 MHz (16 ns), 128 KB external cache
: 16 to 128 MB of memory.
;MicroVAX 3100 Model 88
: ''Waverley/M+''
: Introduced: 8 October 1996
["DEC Upgrades Low-End VAXes To See It Through The Decade". (9 October 1996). ''Computer Business Review''.]
: Last order date: 30 September 2000
[Jesse Lipcon]
"A letter from Jesse Lipcon".
/ref>
: Last ship date: 31 December 2000[Computergram (12 April 1994). "DEC Announcements". ''Computer Business Review''.]
: Processor: KA51, NVAX, 83.34 MHz (12 ns), 512 KB external cache.
;MicroVAX 3100 Model 96
: ''Cheetah++''
: KA56, NVAX, 100 MHz (10 ns)
: 16 to 128 MB of memory.
;MicroVAX 3100 Model 98
: ''Cheetah++''
: Introduced: 8 October 1996
Mayfair
MicroVAX 3500 and MicroVAX 3600
The MicroVAX 3500 and MicroVAX 3600, code named "''Mayfair''", were introduced in September 1987 and were meant to be the higher end complement of the MicroVAX family. These new machines featured more than three times the performance of the MicroVAX II and supported 32 MB of ECC main memory (twice that of the MicroVAX II). The performance improvements over the MicroVAX II resulted from the increased clock rate of the CVAX chip set, which operated at 11.11 MHz (90 ns cycle time) along with a two-level, write-through caching architecture. It used the KA650 CPU module.
MicroVAX 3300 and MicroVAX 3400
The MicroVAX 3300 and MicroVAX 3400, code named ''Mayfair II'', were entry-level to mid-range server computers introduced on 19 October 1988 intended to compete with the IBM AS/400.[Computergram (20 October 1988)]
"DEC Aims New MicroVAX 3300, 3400 At AS/400; New Disk Bus"
''Computer Business Review''. They used the KA640 CPU module.
MicroVAX 3800 and MicroVAX 3900
The MicroVAX 3800 and MicroVAX 3900, code-named "''Mayfair III''", were introduced in April 1989. They were high-end models in the MicroVAX family, replacing the MicroVAX 3500 and MicroVAX 3600, and were intended to compete with the IBM AS/400. At introduction, the starting price of the MicroVAX 3800 was US$81,000 and that of the MicroVAX 3900 was US$120,200."US Prices For DEC's New MicroVAXes"
(11 April 1989). ''Computer Business Review''. A variant of the MicroVAX 3800, the rtVAX 3800, was intended for
real-time computing (RTC) applications such as
computer-aided manufacturing
Computer-aided manufacturing (CAM) also known as computer-aided modeling or computer-aided machining is the use of software to control machine tools in the manufacturing of work pieces. This is not the only definition for CAM, but it is the most ...
(CAM). These systems used the KA655 CPU module, which contained a 16.67 MHz (60 ns cycle time)
CVAX chip set. They supported up to 64 MB of memory.
References
{{DEFAULTSORT:Microvax
DEC minicomputers
Computer-related introductions in 1984
32-bit computers
de:Virtual Address eXtension#Prozessor