View source for Engineering:MicroVAX

{{short description|Family of low-cost minicomputers}}
[[Image:Microvax 3600 (2).jpg|thumb|MicroVAX 3600 (left) with disk drive above and printer on right]]
The '''MicroVAX''' is a discontinued family of low-cost [[Minicomputer|minicomputer]]s developed and manufactured by [[Company:Digital Equipment Corporation|Digital Equipment Corporation]] (DEC). The first model, the MicroVAX I, was introduced in 1983.<ref name=CHW.8>(announced October 1983) {{cite web |website=Computer History Wiki (CHWiki) |url=http://gunkies.org/wiki/MicroVAX_I
|quote=MicroVAX I. Summary. Announcement date: October 1983. FRS date: late 1984. Codename: Seahorse. OS support (VMS):, MicroVMS V1.0
|title=MicroVAX}}</ref><ref>{{cite web 
|url=http://www.yourdictionary.com/microvax
|quote=line of entry-level VAX computers from Digital Equipment. Introduced in 1983, MicroVAX typically shipped with either the [[Software:OpenVMS|OpenVMS]] or ULTRIX [[Operating system|operating system]]s
|title=MicroVAX dictionary definition}}</ref><ref>First Shipped MicroVAX: October 1984</ref> They used processors that implemented the [[VAX]] [[Instruction set architecture|instruction set architecture]] (ISA) and were succeeded by the [[Engineering:VAX 4000|VAX 4000]]. Many members of the MicroVAX family had corresponding VAXstation variants, which primarily differ by the addition of graphics hardware.<ref name=VAXstation>{{cite web|title=Hardware Documentation - Machines DEC - VAX hardware reference|url=http://www.netbsd.org/docs/Hardware/Machines/DEC/vax/vaxstations.html#section:vaxstations|website=www.netbsd.org|access-date=2021-01-21}}</ref> The MicroVAX family supports Digital's [[Software:OpenVMS|VMS]] and ULTRIX operating systems. Prior to VMS V5.0, MicroVAX hardware required a dedicated version of VMS named MicroVMS.<ref name=DEC.prof>{{cite magazine  |magazine=DEC Professional Magazine |title=The VMS/MicroVMS merge
|pages=74–84
|author=Kathleen D. Morse}}</ref><ref>{{cite news |newspaper=Computerworld |date=June 18, 1984 |page=7
|quote=The Micro VMS operating system announced last week by Digital Equipment Corp. for its Microvax I family of microcomputers is a prepackaged version of ...
|title=Micro VMS operating system
|url=https://books.google.com/books?id=aqjZTUJlyygC}}</ref>

==MicroVAX I==
The '''MicroVAX I''', code named "''Seahorse''",<ref>{{cite web
|quote=VAXstation I, code-named "Seahorse," was the first in a new, transitional family of ... 
|title=Loading... Celebrating 30 years of OpenVMS Month Year Caption ...
|url=http://h41379.www4.hpe.com/openvms/30th/timeline.swf}}</ref> introduced in October 1984, was one of DEC's first VAX computers to use [[Engineering:Very-large-scale integration|very-large-scale integration]] (VLSI) technology. The '''KA610''' CPU module (also known as the '''KD32''') contained two custom chips which implemented the ALU and [[Floating-point unit|FPU]] 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).<ref name="micronote22" /> The MicroVAX I used Q-bus memory cards, which limited the maximum memory to 4MiB.<ref name="micronote22">{{cite web|url=https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardware/micronotes/numerical/micronote22.txt|title=Differences between the MicroVAX I and the MicroVAX II CPUs|date=1985-04-28|access-date=2020-12-27|author=Mike Collins|website=ibiblio.org}}</ref> The performance of the MicroVAX I was rated at 0.3 [[VAX Unit of Performance|VUPs]], equivalent to the earlier [[Engineering:VAX-11#VAX-11/730|VAX-11/730]].<ref>{{cite web|url=http://www.vaxmacro.de/vcms.html|access-date=2020-12-27|title=VAX CPU Model Summary|website=vaxmacro.de}}</ref>

==MicroVAX II==
The '''MicroVAX II''', code named "''Mayflower''", was a mid-range MicroVAX introduced in May 1985 and shipped shortly thereafter.<ref name=II.41M>{{cite web
|quote=MicroVAX II. Summary. Announcement date: 14 May 1985. FRS date: May 1985. Codename: Mayflower
|title=MicroVAX II |url=http://gunkies.org/wiki/MicroVAX_II}}</ref><ref>{{cite web |website=Microvax2.org (MicroVAX II Museum)
|title=The MicroVAX II – Workhorse of the 80's
|url=http://microvax2.org/wp/2017/05/25/the-microvax-ii-workhorse-of-the-80s
|quote=Codenamed “Mayflower”, released in 1985, you could have one for $20,000. The MicroVAX II's CPU was the KA630.}}</ref> It ran [[Software:OpenVMS|VAX/VMS]] or, alternatively, [[Software:Ultrix|ULTRIX]], the DEC native Unix operating system. At least one non-DEC operating system was available, BSD Unix from [[Company:MtXinu|MtXinu]].

It used the '''KA630-AA''' CPU module, a quad-height [[Engineering:Q-Bus|Q22-Bus]] module, which featured a [[Engineering:MicroVAX 78032|MicroVAX 78032]] microprocessor and a [[Engineering:MicroVAX 78032#MicroVAX 78132|MicroVAX 78132]] floating-point coprocessor operating at 5&nbsp;MHz (200 ns cycle time). Two [[Gate array|gate array]]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 [[Engineering:Single-board computer|single-board]] MicroVAX II designed for automatic test equipment and manufacturing applications which only ran DEC's real-time [[Software:VAXELN|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.<ref>Computergram (20 January 1987). [http://www.cbronline.com/news/dec_unveils_real_time_microvax_board_run_time_vaxeln "DEC Unveils Real-Time MicroVAX Board, Run-Time VAXELN"]. ''Computer Business Review''.</ref>

=== 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 [[Engineering:MicroVAX 78032|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.<ref name="CBR-1987-05-21">Computergram (21 May 1987). [http://www.cbronline.com/news/dec_france_does_fault_tolerant_microvax_ii_configuration "DEC France Does Fault-Tolerant MicroVAX II Configuration"]{{Dead link|date=April 2020 |bot=InternetArchiveBot |fix-attempted=yes }}. ''Computer Business Review''.</ref>

=== Industrial VAX 630 ===

A MicroVAX II in BA213 enclosure.

=== MicroVAX III ===

BA23- or BA123-enclosure MicroVAX upgraded with KA650 CPU module containing a [[Engineering:CVAX|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.<ref name="CBR-1987-02-11">Computergram (11 February 1987). [http://www.cbronline.com/news/dec_puts_old_wine_into_new_bottles_with_microvax_2000 "DEC Puts Old Wine Into New Bottles With MicroVAX 2000"]. ''Computer Business Review''.</ref> 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 [[Engineering:Q-Bus|Q-Bus]] or any expansion bus. The system could have a [[Company:Shugart Associates|Shugart]]-based harddrive with ST412 interface and [[Modified frequency modulation|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.<ref name="CBR-1987-02-11"/> 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, [[Engineering:CVAX|CVAX]], 11.11 MHz (90 ns)

;MicroVAX 3100 Model 10e
: ''Teammate II''
: KA41-D, [[Engineering:CVAX|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<ref name="CBR-1992-01-29">Computergram (29 January 1992). [http://www.cbronline.com/news/dec_launches_three_microvaxes_designed_and_made_in_ayr "DEC Launches Three MicroVAXes Designed And Made In Ayr"]. ''Computer Business Review''.</ref>
: Introduced: 12 October 1993
: KA45, [[Engineering:CVAX|SOC]], 25 MHz (40 ns)
: 32 MB of memory maximum.

;MicroVAX 3100 Model 40
: ''Waverley/S''
: Entry-level model, developed in Ayr, Scotland<ref name="CBR-1992-01-29"/>
: 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<ref name="CBR-1992-01-29"/>
: Introduced: 12 October 1993
: KA47, [[Engineering:Rigel (microprocessor)|Mariah]], 50 MHz (20 ns), 256 KB external cache
: 72 MB of memory maximum.

;MicroVAX 3100 Model 85
: ''Waverley/M+''
: Introduced: August 1994<ref>[http://www.cbronline.com/news/dec_rushes_to_rescue_of_vax_users_with_four_new_models "DEC Rushes To Rescue Of VAX Users With Four New Models"]. (23 August 1994). ''Computer Business Review''.</ref>
: KA55, [[Engineering:NVAX|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<ref name="CBR-1996-10-09">"DEC Upgrades Low-End VAXes To See It Through The Decade". (9 October 1996). ''Computer Business Review''.</ref>
: Last order date: 30 September 2000<ref name="Letter">Jesse Lipcon. [https://web.archive.org/web/20000815201016/http://www.compaq.com/alphaserver/vax/vax_letter_final.html "A letter from Jesse Lipcon".]</ref>
: Last ship date: 31 December 2000<ref name="Letter"/>
: KA58, NVAX, 62.5 MHz (16 ns), 128 KB external cache
: 64 to 512 MB of memory.

;MicroVAX 3100 Model 90
: ''Cheetah''
: Introduced: 12 October 1993
: Identical to the [[Engineering:VAX 4000|VAX 4000 Model 100]], but uses SCSI instead of [[Digital Storage Systems Interconnect|DSSI]]
: KA50, NVAX, 72 MHz (14 ns), 128 KB external cache
: 128 MB of memory maximum.

;MicroVAX 3100 Model 95
: ''Cheetah+''
: Introduced: 12 April 1994<ref name="CBR-1994-04-12">Computergram (12 April 1994). "DEC Announcements". ''Computer Business Review''.</ref>
: 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<ref name="CBR-1996-10-09"/>
: Last order date: 30 September 2000<ref name="Letter"/>
: Last ship date: 31 December 2000<ref name="Letter"/>
: KA59, NVAX, 100 MHz (10 ns), 512 KB external cache.

;InfoServer 100/150/1000: General purpose storage server (disk, CD-ROM, tape and [[Maintenance Operations Protocol|MOP]] boot server) related to MicroVAX 3100 Model 10, running custom firmware, KA41-C CPU.<ref>{{cite web |url=http://www.vmshobbyist.org/forum/viewthread.php?forum_id=70&thread_id=1310 	|title=VS3100 (sic) to Infoserver? |archive-url=https://web.archive.org/web/20160306100227/http://www.openvmshobbyist.com/forum/viewthread.php?forum_id=70&thread_id=1310 |archive-date=6 March 2016 |website=Hobbyist Computing OpenVMS}}</ref>

== 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 [[Engineering:CVAX|CVAX]] chip set, which operated at 11.11&nbsp;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.<ref name="CBR-1988-10-20">Computergram (20 October 1988). [http://www.cbronline.com/news/dec_aims_new_microvax_3300_3400_at_as400_new_disk_bus "DEC Aims New MicroVAX 3300, 3400 At AS/400; New Disk Bus"]. ''Computer Business Review''.</ref> 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.<ref>[http://www.cbronline.com/news/us_prices_for_decs_new_microvaxes "DEC Hits At AS/400 With MVAX 3800, 3900, Pricing"]. (13 April 1989). ''Computer Business Review''.</ref> 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.<ref>[http://www.cbronline.com/news/dec_hits_at_as400_with_mvax_3800_3900_pricing "US Prices For DEC's New MicroVAXes"]. (11 April 1989). ''Computer Business Review''.</ref> A variant of the MicroVAX 3800, the rtVAX 3800, was intended for [[Real-time computing|real-time computing]] (RTC) applications such as [[Computer-aided manufacturing|computer-aided manufacturing]] (CAM). These systems used the KA655 CPU module, which contained a 16.67&nbsp;MHz (60 ns cycle time) [[Engineering:CVAX|CVAX]] chip set. They supported up to 64 MB of memory.

== References ==

{{Reflist}}

{{DEC hardware}}

{{DEFAULTSORT:Microvax}}

de:Virtual Address eXtension#Prozessor

{{Sourceattribution|MicroVAX|1}}