DEC VAX
Manufacturer:	Digital Equipment Corporation
Byte size:	8 bits (octet)
Address bus size:	32 bits
Peripheral bus:	Unibus, Massbus, Q-Bus, XMI, VAXBI
Architecture:	CISC, virtual memory
Operating systems:	VAX/VMS, Ultrix, BSD UNIX, VAXELN

VAX is a 32-bit computing architecture that supports an orthogonal instruction set (machine language) and virtual addressing (i. The range of Integer values that can be stored in 32 bits is 0 through 4294967295 or −2147483648 through 2147483647 using Two's complement encoding In Computer engineering, computer architecture is the conceptual design and fundamental operational structure of a Computer system Orthogonal instruction set is a term used in Computer engineering. Machine code or machine language is a system of instructions and data executed directly by a Computer 's Central processing unit. e. demand paged virtual memory). In Computer Operating systems that have their Main memory divided into pages, paging (sometimes called swapping) is a transfer Virtual memory is a Computer system technique which gives an application program the impression that it has contiguous working memory while in fact it may be physically It was developed in the mid-1970s by Digital Equipment Corporation (DEC). Digital Equipment Corporation was a pioneering American company in the Computer industry DEC was later purchased by Compaq, which in turn was purchased by Hewlett-Packard. Compaq Computer Corporation was an American Personal computer company founded in 1982 and is now a brand name of Hewlett-Packard.

The VAX has been perceived as the quintessential CISC processing architecture, with its very large number of addressing modes and machine instructions, including instructions for such complex operations as queue insertion/deletion and polynomial evaluation. A complex instruction set computer ( CISC, pronounced like " sisk " is a Microprocessor Instruction set architecture (ISA in which Addressing modes are an aspect of the Instruction set architecture in most Central processing unit (CPU designs A queue (pronounced /kjuː/ is a particular kind of collection in which the entities in the collection are kept in order and the principal (or only operations on the collection In Mathematics, a polynomial is an expression constructed from Variables (also known as indeterminates and Constants using the operations

Contents 1 Name 2 Operating systems 3 History 4 Processor architecture 4.1 Virtual Memory Map 4.2 Privilege Modes 4.3 Processor Status Register 5 VAX models 5.1 Non-VLSI VAXen 5.2 A transitional VAX 5.3 VLSI VAXen 5.4 Miscellaneous 5.5 Clones 6 References 7 External links

Name

"VAX" was originally an acronym for Virtual Address eXtension, both because the VAX was seen as a 32-bit extension of the older 16-bit PDP-11 and because it was (after Prime Computer) an early adopter of virtual memory to manage this larger address space. Acronyms, initialisms, and alphabetisms are Abbreviations that are formed using the initial components in a phrase or name The PDP-11 was a series of 16-bit Minicomputers sold by Digital Equipment Corp Prime Computer was a Natick Massachusetts -based producer of Minicomputers from 1972 until 1992 Virtual memory is a Computer system technique which gives an application program the impression that it has contiguous working memory while in fact it may be physically Early versions of the VAX processor implemented a "compatibility mode" that emulated many of the PDP-11's instructions, and were in fact called VAX-11 to highlight this compatibility and the fact that VAX-11 was an outgrowth of the PDP-11 family. Later versions offloaded the compatibility mode and some of the less used CISC instructions to emulation in the operating system software. The plural form of VAX is usually VAXes, but VAXen is also heard.

Operating systems

The "native" VAX operating system is DEC's VAX/VMS (renamed to OpenVMS in 1991 or 1992 when it was ported to DEC Alpha, "branded" by the X/Open consortium, and modified to comply with POSIX standards^[1]). An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination Open Virtual Memory System ( OpenVMS) initially known just as Virtual Memory System ( VMS) is the name of a High-end Computer server Alpha, originally known as Alpha AXP, was a 64-bit Reduced instruction set computer (RISC Instruction set architecture (ISA developed POSIX (ˈpɒzɪks or "Portable Operating System Interface" is the collective name of a family of related standards specified by the IEEE to define The VAX architecture and VMS operating system were "engineered concurrently" to take maximum advantage of each other, as was the initial implementation of the VAXcluster facility. Product lifecycle management ( PLM) is the process of managing the entire lifecycle of a product from its conception through design and manufacture to service A VMScluster is a Computer cluster involving a group of computers running the OpenVMS operating system Other VAX operating systems have included various releases of BSD UNIX up to 4.3BSD, Ultrix-32 and VAXELN. Ultrix (officially all-caps ULTRIX) was the brand name of Digital Equipment Corporation 's (DEC native Unix systems VAXELN is a Real-time operating system for the VAX family of Computers produced by the Digital Equipment Corporation (DEC of Maynard More recently, NetBSD and OpenBSD support various VAX models and some work has been done on porting Linux to the VAX architecture. NetBSD is a freely redistributable Open source version of the Unix -derivative Berkeley Software Distribution (BSD Computer Operating OpenBSD is a Unix-like computer Operating system descended from Berkeley Software Distribution (BSD a Unix derivative developed at the Linux (commonly pronounced ˈlɪnəks

History

The first VAX model sold was the VAX-11/780, which was introduced on October 25, 1977 at the Digital Equipment Corporation's Annual Meeting of Shareholders[1]. Events 1147 - The Portuguese, under Afonso I, and Crusaders from England and Flanders conquer Lisbon after a Also 1977 (album by Ash. Year 1977 ( MCMLXXVII) was a Common year starting on Saturday (link displays The architect of this model was Bill Strecker. Many different models with different prices, performance levels, and capacities were subsequently created. VAX superminis were very popular in the early 1980s.

For a while the VAX-11/780 was used as a baseline in CPU benchmarks because its speed was about one MIPS. This article is about the use of benchmarks in computing for other uses see Benchmark. Instructions per second (IPS is a measure of a Computer 's processor speed Ironically enough, though, the actual number of instructions executed in 1 second was about 500,000. One VAX MIPS was the speed of a VAX-11/780; a computer performing at 27 VAX MIPS would run the same program roughly 27 times as fast as the VAX-11/780. Within the Digital community the term VUP (VAX Unit of Performance) was the more common term, because MIPS do not compare well across different architectures. The related term cluster VUPs was informally used to describe the aggregate performance of a VAXcluster. A VMScluster is a Computer cluster involving a group of computers running the OpenVMS operating system The performance of the VAX-11/780 still serves as the baseline metric in the BRL-CAD Benchmark, a performance analysis suite included in the BRL-CAD solid modeling software distribution. BRL-CAD is a Constructive solid geometry (CSG Solid modeling Computer-aided design (CAD system

The VAX went through many different implementations. The original VAX was implemented in TTL and filled more than one rack for a single CPU. Transistor–transistor logic ( TTL) is a class of Digital circuits built from Bipolar junction transistors (BJT and Resistors It is called CPU implementations that consisted of multiple ECL gate array or macrocell array chips included the 8600, 8800 superminis and finally the 9000 mainframe class machines. In electronics emitter-coupled logic, or ECL, is a Logic family in which current is steered through bipolar transistors to implement Logic A gate array or uncommitted logic array ( ULA) is an approach to the design and manufacture of Application-specific integrated circuits (ASICs A macrocell array is an approach to the design and manufacture of ASICs Essentially it is a small step up from the otherwise similar Gate array, but rather than being Mainframes (often colloquially referred to as Big Iron) are Computers used mainly by large organizations for critical applications typically bulk data CPU implementations that consisted of multiple MOSFET custom chips included the 8100 and 8200 class machines. The metal–oxide–semiconductor field-effect transistor ( MOSFET, MOS-FET, or MOS FET) is a device used to amplify or switch electronic signals

The MicroVAX I represented a major transition within the VAX family. At the time of its design, it was not yet possible to implement the full VAX architecture as a single VLSI chip (or even a few VLSI chips as was later done with the V-11 CPU of the VAX 8200/8300). Instead, the MicroVAX I was the first VAX implementation to move most of the complexity of the VAX instruction set into emulation software, preserving just the core instructions in hardware. This new partitioning substantially reduced the amount of microcode required and was referred to as the "MicroVAX" architecture. Microprogramming (ie writing microcode) is a method that can be employed to implement Machine instructions in a CPU relatively easily often using less In the MicroVAX I, the ALU and registers were implemented as a single gate-array chip while the rest of the machine control was conventional logic.

A full VLSI (microprocessor) implementation of the MicroVAX architecture then arrived with the MicroVAX II's 78032 (or DC333) CPU and 78132 (DC335) FPU. A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated The 78032 was the first microprocessor with an on-board memory management unit^[2] The MicroVAX II was based on a single, quad-sized processor board which carried the processor chips and ran the MicroVMS or Ultrix-32 operating systems. A memory management unit ( MMU) sometimes called paged memory management unit ( PMMU) is a Computer hardware component responsible for handling Ultrix (officially all-caps ULTRIX) was the brand name of Digital Equipment Corporation 's (DEC native Unix systems An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination The machine featured 1 MB of on-board memory and a Q22-bus interface with DMA transfers. The Q-bus (also known as the LSI-11 Bus) was one of several bus technologies used with PDP and MicroVAX computer systems manufactured by the Digital Direct memory access ( DMA) is a feature of modern Computers and Microprocessors that allows certain hardware subsystems within the computer to access system The MicroVAX II was succeeded by many further MicroVAX models with much improved performance and memory.

Further VLSI VAX processors followed in the form of the V-11, CVAX, SOC ("System On Chip", a single-chip CVAX), Rigel, Mariah and NVAX implementations. The VAX microprocessors extended the architecture to inexpensive workstations and later also supplanted the high-end VAX models. A workstation, such as a Unix workstation, RISC workstation or Engineering workstation, is a high-end Microcomputer This wide range of platforms (mainframe to workstation) using one architecture was unique in the computer industry at that time. Sundry graphics were etched onto the CVAX microprocessor die. The phrase CVAX. . . when you care enough to steal the very best was etched in broken Russian as a play on a Hallmark Cards slogan, intended as a message to Soviet engineers who were known to be both purloining DEC computers for military applications, along with reverse engineering their chip design. Russian ( transliteration:,) is the most geographically widespread language of Eurasia, the most widely spoken of the Slavic languages Hallmark Cards is a privately owned American company based in Kansas City Missouri. A soviet (сове́т, "council" originally was a workers' local council in late Imperial Russia. Reverse engineering (RE is the process of discovering the technological principles of a device object or system through analysis of its structure function and operation ^{[3] [4]}

The VAX architecture was eventually superseded by RISC technology. In 1989 DEC introduced a range of workstations based on processors from MIPS Technologies and running Ultrix. Year 1989 ( MCMLXXXIX) was a Common year starting on Sunday (link displays 1989 Gregorian calendar) The DECstation was a brand of computers used by DEC, and refers to three distinct lines of computer systems&mdashthe first released in 1978 as a Word processing MIPS Technologies Inc ( formerly MIPS Computer Systems, is most widely known for developing the MIPS architecture and a series of pioneering RISC Ultrix (officially all-caps ULTRIX) was the brand name of Digital Equipment Corporation 's (DEC native Unix systems In 1992 DEC introduced their own RISC processor, the Alpha (originally named Alpha AXP), a high performance 64-bit architecture capable of running OpenVMS. Year 1992 ( MCMXCII) was a Leap year starting on Wednesday (link will display full 1992 Gregorian calendar) Alpha, originally known as Alpha AXP, was a 64-bit Reduced instruction set computer (RISC Instruction set architecture (ISA developed '64-bit' CPUs have existed in Supercomputers since the 1960s and in RISC -based workstations and servers since the early 1990s.

In August 2000, Compaq announced that the remaining VAX models would be discontinued by the end of the year[2]. By 2005 all manufacturing of VAX computers had ceased, but old systems remain in widespread use.

The SRI CHARON-VAX and SIMH software-based VAX emulators remain available. SIMH is a highly portable multi-system Emulator which runs on Windows, Linux, Mac OS X, FreeBSD, OpenBSD, NetBSD

Processor architecture

Virtual Memory Map

The VAX virtual memory is divided into four sections, each of which is one gigabyte (1 GiB) in size:

Section	Address Range
P0	0x00000000 - 0x3fffffff
P1	0x40000000 - 0x7fffffff
S0	0x80000000 - 0xbfffffff
S1	0xc0000000 - 0xffffffff

For VMS, P0 was used for user process space, P1 for process stack, S0 for the operating system, and S1 was reserved. A gibibyte (a contraction of gi ga bi nary byte) is a unit of Information or Computer storage, abbreviated GiB.

Privilege Modes

The VAX has four privilege modes:

No.	Mode	VMS Usage	Notes
0	Kernel	OS Kernel	Highest Privilege Level
1	Executive	File System
2	Supervisor	Shell (DCL)
3	User	Normal Programs	Lowest Privilege Level

Processor Status Register

CM	TP	MBZ	FD	IS	cmod	pmod	MBZ	IPL	MBZ	DV	FU	IV	T	N	Z	V	C
31	30	29	27	26	25	23	21	20	15	7	6	5	4	3	2	1	0

Bits	Meaning
31	PDP-11 compatibility mode
30	trace pending
29:28	MBZ (must be zero)
27	first part done (interrupted instruction)
26	interrupt stack
25:24	current privilege mode
23:22	previous privilege mode
21	MBZ (must be zero)
20:16	IPL (interrupt priority level)
15:8	MBZ (must be zero)
7	decimal overflow trap enable
6	floating-point underflow trap enable
5	integer overflow trap enable
4	trace
3	negative
2	zero
1	overflow
0	carry

VAX models

Listed in roughly chronological order. The codenames used during development within Digital Equipment Corporation are shown in italic. VAX systems can be broadly classified into those with non-VLSI processors and those with VLSI processors with the MicroVAX-I being a transitional design:

Non-VLSI VAXen

VAX 11/780

Star, TTL CPU, October 1977^[5]

VAX 11/750

Comet, More-compact, lower-performance TTL gate array-based implementation, October 1980

VAX 11/751

ruggedized rack-mount 11/750

VAX 11/730

Nebula, Still-more-compact, still-lower-performance bit slice implementation, April 1982

VAX 11/782

Atlas, Dual-processor 11/780

VAX 11/784

VAXimus, Four 11/780 CPUs sharing a single MA780 memory unit. Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside Transistor–transistor logic ( TTL) is a class of Digital circuits built from Bipolar junction transistors (BJT and Resistors It is called A gate array or uncommitted logic array ( ULA) is an approach to the design and manufacture of Application-specific integrated circuits (ASICs Very rare

VAX 11/785

Superstar, Faster 11/780, April 1984

VAX 11/787

dual processor 11/785

VAX 11/788

VISQ

VAX 11/725

LCN, Low-Cost Nebula

VAX 8600

Venus, aka 11/790 during development, ECL gate array CPU, October 1984

VAX 8650

Morningstar, aka 11/795 during development, a faster 8600, last model to use SBI backplane also used by VAX 11/78x models, last model to have PDP-11 compatibility mode. In electronics emitter-coupled logic, or ECL, is a Logic family in which current is steered through bipolar transistors to implement Logic A gate array or uncommitted logic array ( ULA) is an approach to the design and manufacture of Application-specific integrated circuits (ASICs The Synchronous Backplane Interconnect ( SBI) was the internal processor-memory bus used by early VAX computers manufactured by the Digital Equipment Corporation All subsequent 8000 series models use VAXBI instead of SBI

VAX 8x00

Gemini, Fall-back in case the LSI-based Scorpio failed (never shipped)

VAX 8500

Flounder, Single-processor, deliberately-slowed VAX 8700

VAX 8530

Skipjack, Single-processor, less-slowed VAX 8700

VAX 8550

Skipjack, Single-processor 8800, unexpandable

VAX 8700

Nautilus, Single-processor Nautilus, expandable to full 8800

VAX 8800

Nautilus, Dual-processor ECL Macrocell array-based implementation, January 1986. The VAXBI Bus was a Computer bus designed and sold by the Digital Equipment Corporation ( DEC) of Maynard, Massachusetts. A macrocell array is an approach to the design and manufacture of ASICs Essentially it is a small step up from the otherwise similar Gate array, but rather than being Later also known as VAX 8820N

VAX 8810/8820/8830/8840

Polarstar, a Nautilus variant with one to four processors and an updated console processor

VAX 8974/8978

cluster comprising four or eight VAX 8810s respectively, January 1987

VAX 9000

Aridus, Air-cooled. Originally designed to be water-cooled, named Aquarius, ECL macrocell array CPU, VAXBI, October 1989^[6]

VAX 9000 Model 110

VAX 9000 Model 210

VAX 9000 Model 310

VAX 9000 Model 4x0

x = number of processors, 1–4

A transitional VAX

MicroVAX/VAXstation I

Seahorse, KD32 CPU, October 1984

VLSI VAXen

MicroVAX series

some models also sold as VAXservers

MicroVAX II

Mayflower, KA630 CPU, May 1985

Industrial VAX 630

MicroVAX II in BA213 enclosure

MicroVAX III

BA23- or BA123-enclosure MicroVAX upgraded with KA650 CVAX CPU

MicroVAX III+

BA23- or BA123-enclosure MicroVAX upgraded with KA655 CPU

VAX 4

BA23- or BA123-enclosure MicroVAX upgraded with KA660 CPU

MicroVAX 2000

TeamMate, desktop form factor, February 1987

MicroVAX 3100 series

desktop form-factor, 1987 onwards

MicroVAX 3100 Model 10

TeamMate II, KA41-A CVAX processor

MicroVAX 3100 Model 10e

TeamMate II, KA41-D CVAX+ processor

MicroVAX 3100 Model 20

Model 10 in larger enclosure

MicroVAX 3100 Model 20e

Model 20 in larger enclosure

MicroVAX 3100 Model 30

Waverley/S, KA45 SOC CPU

MicroVAX 3100 Model 40

Model 30 in larger enclosure

MicroVAX 3100 Model 80

Waverley/M, KA47 Mariah CPU

MicroVAX 3100 Model 85

Waverley/M+, KA55 NVAX CPU

MicroVAX 3100 Model 88

Waverley/M+, KA58 NVAX CPU

MicroVAX 3100 Model 90

Cheetah, KA50 NVAX CPU

MicroVAX 3100 Model 95

Cheetah+, KA51 NVAX CPU

MicroVAX 3100 Model 96

Cheetah++, KA56 NVAX CPU

MicroVAX 3100 Model 98

Cheetah++, KA59 NVAX CPU

InfoServer 100/150/1000

General purpose storage server (disk, CD-ROM, tape and MOP boot server) related to MicroVAX 3100 Model 10, running custom firmware, KA41-C CPU

MicroVAX 3300/3400

Mayfair, used KA640 CPU card

MicroVAX 3500/3600

Mayfair-II, used KA650 CPU card, September 1987

MicroVAX 3800/3900

Mayfair-III, used KA655 CPU card

VAXstation series

VAXstation II

MicroVAX II workstation configuration

VAXstation II/GPX

Caylith, hardware-enhanced, high-performance color graphics, December 1985

VAXstation 2000

VAXstar MicroVAX 2000 workstation configuration

VAXstation 3100 series

VAXstation 3100 Model 30

PVAX, KA42-A CVAX CPU

VAXstation 3100 Model 38

PVAX rev#7, KA42-B CVAX CPU

VAXstation 3100 Model 40

Model 30 in larger enclosure

VAXstation 3100 Model 48

Model 38 in larger enclosure

VAXstation 3100 Model 76

RigelMAX, KA43-A Rigel CPU

VT1300

X terminal (essentially a diskless VAXstation 3100 Model 30)

VAXstation 3200/3500

Mayfair/GPX, KA650 CVAX CPU

VAXstation 3520/3540

Firefox, two or four KA60 CVAX processors

VAXstation 4000

TURBOchannel bus

VAXstation 4000/VLC aka Model 30

PVAX2/VLC, KA48 SOC ("System On Chip") CPU, slim pizza box, accepting standard 72-pin parity SIMM modules

VAXstation 4000 Model 60

PMariah, KA46 Mariah CPU

VAXstation 4000 Model 90

Cougar, KA49-A NVAX CPU

VAXstation 4000 Model 90A

Cougar+, KA49-A NVAX CPU

VAXstation 4000 Model 96

Cougar++, KA49-C NVAX CPU

VXT 2000

X terminal based on SOC CPU

VAXstation 8000

Lynx, very rare high-end 3D workstation based on VAX 8200

VAX 4000 series

MicroVAX name dropped

VAX 4000 Model 50

VAXbrick, KA600 NVAX processor, CPU upgrade for MicroVAX 3x00 or VAX 4000-200

VAX 4000 Model 100/100A

Cheetah-Q, KA52 NVAX processor

VAX 4000 Model 105A

Cheetah-Q+, faster KA53 NVAX processor

VAX 4000 Model 106A/108

Cheetah-Q++, faster KA54/KA57 NVAX processor

VAX 4000 Model 200

Spitfire, KA660 SOC processor

VAX 4000 Model 300

Pele, KA670 Rigel 1. The Maintenance Operation Protocol (MOP is used for utility services such as uploading and downloading system software remote testing and problem diagnosis See also HP X-Terminals TURBOchannel is an open Computer bus developed by DEC by during the late 1980s and early 1990s 5 µm CMOS processor chipset,^[7] mid-1989

VAX 4000 Model 400

Omega, KA675 NVAX processor

VAX 4000 Model 500/500A

Omega/N, KA680/KA681 NVAX processor

VAX 4000 Model 505A/600/600A

Omega/N+, KA690/KA691 NVAX processor

VAX 4000 Model 700A

Legacy, KA692 NVAX processor

VAX 4000 Model 705A

Legacy+, KA694 NVAX processor

VAX 8200/8300

Scorpio, one or two V-11 CPUs respectively, VAXBI backplane, January 1986

VAX 8250/8350

Faster Scorpios

VAX 6000 series 

x = number of processors, max 6 for the 600 series

VAX 6000 Model 2x0 aka VAX 62x0 series

Calypso,: used CVAX chipset, April 1988

VAX 6000 Model 3x0 aka VAX 63x0 series

Hyperion, CVAX+ 1. The VAXBI Bus was a Computer bus designed and sold by the Digital Equipment Corporation ( DEC) of Maynard, Massachusetts. 5 µm CMOS processor chipset, January 1989

VAX 6000 Model 4x0 aka VAX 64x0 series

Calypso/XRP, Rigel 1. 5 µm CMOS chipset, mid-1989

VAX 6000 Model 5x0 aka VAX 65x0 series

Calypso/XMP, Mariah 1. 0 µm CMOS chipset, October 1990

VAX 6000 Model 6x0 aka VAX 66x0 series

Neptune, NVAX 0. 75 µm CMOS chipset, November 1991

VAX 6333

prepackaged cluster of VAX 6000 Model 300 series

VAX 7000 series

VAX 7000 Model 6x0

Laser/Neon, Up to six KA7AA NVAX+ processors, field-upgradable to Alpha AXP 64-bit processor(s) (ie. Alpha, originally known as Alpha AXP, was a 64-bit Reduced instruction set computer (RISC Instruction set architecture (ISA developed DEC 7000 AXP configuration), July 1992

VAX 7000 Model 7x0

Laser/Krypton, KA7AB NVAX5 processor(s)

VAX 7000 Model 8x0

Laser/Krypton+, faster KA7AC NVAX5 processor(s)

VAX 10000 Model 6x0

Blazer/Neon, VAX 7000 Model 6x0 with more I/O capacity and UPS as standard

VAXft fault-tolerant series

VAXft 3000 Model 310

Cirrus, CVAX+ CPUs, two-processor, lock-stepped fault tolerant system, February 1990

VAXft Model 110

slower, lower cost Cirrus

VAXft Model 410/610/612

Cirrus II, SOC CPUs

VAXft Model 810

Jetstream, NVAX+ CPUs

Miscellaneous

VAXstation 100 (VS100)

Graphics terminal based on a MC68000 microprocessor, intended to connect to a VAX system via Unibus, May 1983. The DEC 7000 AXP and DEC 10000 AXP are a series of high-end Multiprocessor server computers developed and manufactured by Digital Equipment Corporation An uninterruptible power supply ( UPS) also known as a continuous power supply ( CPS) or a battery backup is a device which maintains a continuous In Engineering, Fault-tolerant design, also known as fail-safe design, is a design that enables a system to continue operation possibly at a reduced level (also known A computer terminal is an electronic or electromechanical hardware device that is used for entering data into and displaying data from a Computer or a Computing The Motorola 68000 is a 16/32-bit CISC Microprocessor core designed and marketed by Freescale Semiconductor (formerly Motorola Semiconductor A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated The Unibus was the earliest of several bus technologies used with PDP-11 and early VAX systems manufactured by the Digital Equipment Corporation ^[8]

VAXstation 500

Color successor to VAXstation 100, October 1985. ^[9]

VAX XXXX

BVAX, High-end VAX (never shipped)

Clones

A number of clones of VAX models, both authorized and unauthorized, were produced. Examples include:

• Systime Ltd. of the United Kingdom produced clones of early VAX models such as the Systime 8750 (equivalent to the VAX 11/750). The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located ^[10]

• Norden Systems produced the ruggedized, Military-specification MIL VAX series. ^[1]

• The Hungarian Central Research Institute for Physics (KFKI) produced a series of clones of early VAX models, the TPA-11/540, 560 and 580. Hungary (Magyarország 'mɔɟɔrorsaːg) officially in English the Republic of Hungary ( Magyar Köztársaság, literally Magyar (Hungarian Republic ^[11]

References

External links

• OpenVMS.org For OpenVMS users; has some VAX coverage
• VAX Performance Upgrades from Nemonix Engineering
• VAX timeline – From HP's website
• DEC Microprocessors
• SRI CHARON-VAX Emulator
• NetBSD VAX Hardware Documentation
• Paul Hardy's VMS CPU Model Summary
• VAXarchive
• Chuck's House of VAX
• OpenBSD on VAX
• OpenVMS FAQ

Open Virtual Memory System ( OpenVMS) initially known just as Virtual Memory System ( VMS) is the name of a High-end Computer server

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