VAX
Encyclopedia
| colspan="2" | DEC VAX
|-
| colspan=2 align=center |
|-
|Manufacturer:
|Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
|-
|Byte size:
|8 bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s (octet
Octet (computing)
An octet is a unit of digital information in computing and telecommunications that consists of eight bits. The term is often used when the term byte might be ambiguous, as there is no standard for the size of the byte.-Overview:...
)
|-
|Address bus size:
|32 bits
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
|-
|Peripheral bus:
|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.-History:...
, Massbus
Massbus
The Massbus was a high-performance computer input/output bus designed in the 1970s by the Digital Equipment Corporation of Maynard, Massachusetts....
, Q-Bus
Q-Bus
The Q-bus was one of several bus technologies used with PDP and MicroVAX computer systems manufactured by the Digital Equipment Corporation of Maynard, Massachusetts....
, XMI, VAXBI
|-
|Architecture:
|CISC
Complex instruction set computer
A complex instruction set computer , is a computer where single instructions can execute several low-level operations and/or are capable of multi-step operations or addressing modes within single instructions...
, virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
|-
|Operating systems:
|VAX/VMS, Ultrix
Ultrix
Ultrix was the brand name of Digital Equipment Corporation's native Unix systems. While ultrix is the Latin word for avenger, the name was chosen solely for its sound.-History:...
, BSD UNIX
Berkeley Software Distribution
Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...
, VAXELN
VAXELN
VAXELN is a real-time operating system for the VAX family of computers produced by the Digital Equipment Corporation of Maynard, Massachusetts.As with RSX-11 and VMS, Dave Cutler was the principal force behind the development of this operating system...
>
VAX was an instruction set architecture (ISA) developed by Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
(DEC) in the mid-1970s. A 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....
complex instruction set computer
Complex instruction set computer
A complex instruction set computer , is a computer where single instructions can execute several low-level operations and/or are capable of multi-step operations or addressing modes within single instructions...
(CISC) ISA, it was designed to extend or replace DEC's various Programmed Data Processor
Programmed Data Processor
Programmed Data Processor was the name of a series of minicomputers made by Digital Equipment Corporation. The name 'PDP' intentionally avoided the use of the term 'computer' because, at the time of the first PDPs, computers had a reputation of being large, complicated, and expensive machines, and...
(PDP) ISAs. The VAX name was also used by DEC for a family of computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
systems based on this processor architecture.
The VAX architecture's primary features were virtual addressing (for example demand paged
Paging
In computer operating systems, paging is one of the memory-management schemes by which a computer can store and retrieve data from secondary storage for use in main memory. In the paging memory-management scheme, the operating system retrieves data from secondary storage in same-size blocks called...
virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
) and its orthogonal instruction set
Orthogonal instruction set
Orthogonal instruction set is a term used in computer engineering. A computer's instruction set is said to be orthogonal if any instruction can use data of any type via any addressing mode...
. VAX has been perceived as the quintessential CISC ISA, with its very large number of programmer-friendly addressing mode
Addressing mode
Addressing modes are an aspect of the instruction set architecture in most central processing unit designs. The various addressing modes that are defined in a given instruction set architecture define how machine language instructions in that architecture identify the operand of each instruction...
s and machine instructions, highly orthogonal architecture, and instructions for complex operations such as queue insertion or deletion and polynomial
Polynomial
In mathematics, a polynomial is an expression of finite length constructed from variables and constants, using only the operations of addition, subtraction, multiplication, and non-negative integer exponents...
evaluation.
Name
"VAX" is originally an acronym for Virtual Address eXtension, both because the VAX was seen as a 32-bit extension of the older 16-bit16-bit
-16-bit architecture:The HP BPC, introduced in 1975, was the world's first 16-bit microprocessor. Prominent 16-bit processors include the PDP-11, Intel 8086, Intel 80286 and the WDC 65C816. The Intel 8088 was program-compatible with the Intel 8086, and was 16-bit in that its registers were 16...
PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
and because it was (after Prime Computer
Prime Computer
Prime Computer, Inc. was a Natick, Massachusetts-based producer of minicomputers from 1972 until 1992. The alternative spellings "PR1ME" and "PR1ME Computer" were used as brand names or logos by the company.-Founders:...
) an early adopter of virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
to manage this larger address space. 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.
Instruction set
The VAX instruction set was designed to be powerful and orthogonal. When introduced, many programs were written in assembler language, so having a "user-friendly" instruction set was important. In time, as more programs were written in higher-level language, the instruction set became less visible, and the only ones much concerned about it were compiler writers.Arguably, the VAX instruction set was too complicated. One problem is that it is difficult to predict the start of the next instruction, which becomes important for performance. In most designs, one simply has to look at the opcode to know the instruction length, if even there are different-size instructions at all. Also, people found that complicated instructions were often slower than a sequence of simple instructions. Annoyingly, it was different from model to model as to whether the complicated instructions would be a gain. This spurred research into RISC computing. Later RISC processors would beat the VAX by a significant margin.
Operating systems
The "native" VAX operating systemOperating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
is DEC's VAX/VMS
OpenVMS
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
(renamed to OpenVMS in 1991 or 1992 when it was ported to Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
,
"branded" by the X/Open consortium,
and modified to comply with POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
standards). 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
VMScluster
A VMScluster is a computer cluster involving a group of computers running the OpenVMS operating system. Whereas tightly coupled multiprocessor systems run a single copy of the operating system, a VMScluster is loosely coupled: each machine runs its own copy of OpenVMS, but the disk storage, lock...
facility. Other VAX operating systems have included various releases of BSD UNIX
Berkeley Software Distribution
Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...
up to 4.3BSD, Ultrix
Ultrix
Ultrix was the brand name of Digital Equipment Corporation's native Unix systems. While ultrix is the Latin word for avenger, the name was chosen solely for its sound.-History:...
-32, VAXELN
VAXELN
VAXELN is a real-time operating system for the VAX family of computers produced by the Digital Equipment Corporation of Maynard, Massachusetts.As with RSX-11 and VMS, Dave Cutler was the principal force behind the development of this operating system...
and Xinu
Xinu
Xinu is a Unix-like operating system originally developed by Douglas Comer for instructional purposes at Purdue University in the 1980s. The name is both recursive, and is "Unix" spelled backwards...
. More recently, NetBSD
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...
and OpenBSD
OpenBSD
OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution , a Unix derivative developed at the University of California, Berkeley. It was forked from NetBSD by project leader Theo de Raadt in late 1995...
support various VAX models and some work has been done on porting Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
to the VAX architecture.
History
For a while the VAX-11/780 was used as a baseline in CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
benchmark
Benchmark (computing)
In computing, a benchmark is the act of running a computer program, a set of programs, or other operations, in order to assess the relative performance of an object, normally by running a number of standard tests and trials against it...
s because its speed was about one MIPS. 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 faster than 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
VMScluster
A VMScluster is a computer cluster involving a group of computers running the OpenVMS operating system. Whereas tightly coupled multiprocessor systems run a single copy of the operating system, a VMScluster is loosely coupled: each machine runs its own copy of OpenVMS, but the disk storage, lock...
. The performance of the VAX-11/780 still serves as the baseline metric in the BRL-CAD Benchmark
BRL-CAD
BRL-CAD is a constructive solid geometry solid modeling computer-aided design system. It includes an interactive geometry editor, ray tracing support for graphics rendering and geometric analysis, computer network distributed framebuffer support, scripting, image-processing and signal-processing...
, a performance analysis suite included in the BRL-CAD solid modeling software distribution. The VAX-11/780 included a subordinate stand-alone LSI-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
computer that performed microcode load, booting, and diagnostic functions for the parent computer. This was dropped from subsequent VAX models. Enterprising VAX-11/780 users could therefore run three different Digital Equipment Corporation operating systems: VMS on the VAX processor, or either RSX-11M or RT-11 on the LSI-11.
Transistor-transistor logic
Transistor–transistor logic is a class of digital circuits built from bipolar junction transistors and resistors. It is called transistor–transistor logic because both the logic gating function and the amplifying function are performed by transistors .TTL is notable for being a widespread...
and filled more than one rack for a single CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
. CPU implementations that consisted of multiple ECL
Emitter coupled logic
In electronics, emitter-coupled logic , is a logic family that achieves high speed by using an overdriven BJT differential amplifier with single-ended input, whose emitter current is limited to avoid the slow saturation region of transistor operation....
gate array
Gate array
A gate array or uncommitted logic array is an approach to the design and manufacture of application-specific integrated circuits...
or macrocell array
Macrocell array
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 a prefabricated array of simple logic gates, the macrocell array is a prefabricated array of higher-level logic functions such as...
chips included the VAX 8600 and 8800
VAX 8000
The VAX 8000 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture .- VAX 8600 :...
superminis and finally the VAX 9000
VAX 9000
The VAX 9000, code named Aridus, was a family of high-end minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . The VAX 9000 was positioned by Digital as its first mainframe...
mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
class machines. CPU implementations that consisted of multiple MOSFET
MOSFET
The metal–oxide–semiconductor field-effect transistor is a transistor used for amplifying or switching electronic signals. The basic principle of this kind of transistor was first patented by Julius Edgar Lilienfeld in 1925...
custom chips included the 8100 and 8200 class machines.
The MicroVAX
MicroVAX
The MicroVAX was a family of low-end minicomputers developed and manufactured by Digital Equipment Corporation . The first model, the MicroVAX I, was introduced in 1984...
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
V-11
The V-11, code-named "Scorpio", is a microprocessor chip set implementation of the VAX instruction set architecture developed and fabricated by Digital Equipment Corporation .- History :...
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
Microcode
Microcode is a layer of hardware-level instructions and/or data structures involved in the implementation of higher level machine code instructions in many computers and other processors; it resides in special high-speed memory and translates machine instructions into sequences of detailed...
required and was referred to as the "MicroVAX" architecture. 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
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
) implementation of the MicroVAX architecture then arrived with the MicroVAX II's 78032
MicroVAX 78032
The MicroVAX 78032 is a microprocessor developed and fabricated by Digital Equipment Corporation that implemented a subset of the VAX instruction set architecture . The 78032 was used exclusively in DEC's VAX-based systems, starting with the MicroVAX II in 1985...
(or DC333) CPU and 78132 (DC335) FPU. The 78032 was the first microprocessor with an on-board memory management unit
Memory management unit
A memory management unit , sometimes called paged memory management unit , is a computer hardware component responsible for handling accesses to memory requested by the CPU...
The MicroVAX II was based on a single, quad-sized processor board which carried the processor chips and ran the MicroVMS or Ultrix
Ultrix
Ultrix was the brand name of Digital Equipment Corporation's native Unix systems. While ultrix is the Latin word for avenger, the name was chosen solely for its sound.-History:...
-32 operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s. The machine featured 1 MB of on-board memory and a Q22-bus
Q-Bus
The Q-bus was one of several bus technologies used with PDP and MicroVAX computer systems manufactured by the Digital Equipment Corporation of Maynard, Massachusetts....
interface with DMA
Direct memory access
Direct memory access is a feature of modern computers that allows certain hardware subsystems within the computer to access system memory independently of the central processing unit ....
transfers. 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
CVAX
The CVAX is a microprocessor chip set developed and fabricated by Digital Equipment Corporation that implemented the VAX instruction set architecture...
, SOC ("System On Chip", a single-chip CVAX), Rigel
Rigel (microprocessor)
Rigel was a microprocessor chip set developed and fabricated by Digital Equipment Corporation that implemented the VAX instruction set architecture . It was introduced on 11 July 1989 with the introduction of the VAX 6000 Model 400, the first system to feature the chip set. Rigel was also used in...
, Mariah and NVAX
NVAX
The NVAX is a microprocessor developed and fabricated by Digital Equipment Corporation that implemented the VAX instruction set architecture . The NVAX was a high-end single-chip VAX microprocessor. A variant of the NVAX, the NVAX+, differed in the bus interface and external cache supported, but...
implementations. The VAX microprocessors extended the architecture to inexpensive workstation
Workstation
A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...
s and later also supplanted the high-end VAX models. 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
Russian language
Russian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...
as a play on a Hallmark Cards
Hallmark Cards
Hallmark Cards is a privately owned American company based in Kansas City, Missouri. Founded in 1910 by Joyce C. Hall, Hallmark is the largest manufacturer of greeting cards in the United States. In 1985, the company was awarded the National Medal of Arts....
slogan, intended as a message to Soviet engineers who were known to be both purloining DEC computers for military applications, along with reverse engineering
Reverse engineering
Reverse engineering is the process of discovering the technological principles of a device, object, or system through analysis of its structure, function, and operation...
their chip design.
The VAX architecture was eventually superseded by RISC technology. In 1989 DEC introduced a range of workstations and servers that ran Ultrix
Ultrix
Ultrix was the brand name of Digital Equipment Corporation's native Unix systems. While ultrix is the Latin word for avenger, the name was chosen solely for its sound.-History:...
, the DECstation
DECstation
The DECstation was a brand of computers used by DEC, and refers to three distinct lines of computer systems—the first released in 1978 as a word processing system, and the latter two both released in 1989. These comprised a range of computer workstations based on the MIPS architecture and a...
and DECsystem
DECsystem
DECsystem was a line of server computers from Digital Equipment Corporation. They were based on MIPS architecture processors and ran DEC's version of the UNIX operating system, called Ultrix...
respectively, based on processors that implemented the MIPS architecture
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...
. In 1992 DEC introduced their own RISC instruction set architecture, the Alpha AXP
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
(later renamed Alpha), and their own Alpha-based microprocessor, the DECchip 21064
Alpha 21064
The Alpha 21064 is a microprocessor developed and fabricated by Digital Equipment Corporation that implemented the Alpha instruction set architecture . It was introduced as the DECchip 21064 before it was renamed in 1994. The 21064 is also known by its code name, EV4...
, a high performance 64-bit
64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...
design capable of running OpenVMS.
In August 2000, Compaq announced that the remaining VAX models would be discontinued by the end of the year. By 2005 all manufacturing of VAX computers had ceased, but old systems remain in widespread use.
The Stromasys CHARON-VAX and SIMH
SIMH
SIMH is a highly portable, multi-system emulator which runs on Windows, Linux, Mac OS X, FreeBSD, OpenBSD, NetBSD, OpenVMS, and other operating systems...
software-based VAX emulators remain available.
Virtual memory map
The VAX virtual memory is divided into four sections, each of which is one gigabyte 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.
Privilege modes
The VAX has four hardware implemented privilege modes (see Processor Status Register):| 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 |
Addressing modes
The VAX supports many addressing modes: literal, register, postincrement, predecrement, register deferred, postincrement deferred, predecrement deferred, displacement (byte, word, long), displacement (byte, word, long) deferred; also indexed, which may be combined with many of these. An "immediate" mode is synonymous with program counter (PC) postincrement, and many addressing modes could use the program counter (which is also R15) instead of other registers. This provided for easy generation of position-independent code through "PC-relative" addressing. The VAX also has some "load effective address" instructions, which do not access memory but compute the address that should be used.VAX-based systems
The first VAX-based system was the VAX-11/780, a member of the VAX-11VAX-11
The VAX-11 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . The VAX-11/780 was the first VAX computer.- VAX-11/780 :...
family. The high-end VAX 8600 replaced the VAX-11/780 in October 1984 and was joined by the entry-level MicroVAX
MicroVAX
The MicroVAX was a family of low-end minicomputers developed and manufactured by Digital Equipment Corporation . The first model, the MicroVAX I, was introduced in 1984...
minicomputers and the VAXstation
VAXstation
The VAXstation was a family of workstation computers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture .- VAXstation I :...
workstations in the mid-1980s. The MicroVAX was superseded by the VAX 4000
VAX 4000
The VAX 4000 was a family of low-end minicomputers developed and manufactured by Digital Equipment Corporation using microprocessors implementing the VAX instruction set architecture . The VAX 4000 succeeded the MicroVAX family...
, the VAX 8000 was superseded by the VAX 6000
VAX 6000
The VAX 6000 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture...
in the late 1980s and the mainframe-class VAX 9000
VAX 9000
The VAX 9000, code named Aridus, was a family of high-end minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . The VAX 9000 was positioned by Digital as its first mainframe...
was introduced. In the early 1990s, the fault-tolerant VAXft
VAXft
The VAXft was a family of fault-tolerant minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . "VAXft" stood for "Virtual Address Extension, fault tolerant". These systems ran the OpenVMS operating system, and...
was introduced, as were the Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
compatible VAX 7000/10000
VAX 7000/10000
The VAX 7000 and VAX 10000 were a series of high-end multiprocessor minicomputers developed and manufactured by Digital Equipment Corporation , introduced in July 1992. These systems used microprocessors implementing the VAX instruction set architecture...
. A variant of various VAX-based systems were sold as the VAXserver
VAXserver
The VAXserver was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . The VAXserver models were variants of various VAX-based computers which were configured to only run operating systems which...
.
Cancelled systems
Cancelled systems include the "BVAX", a high-end ECLEmitter-coupled logic
In electronics, emitter-coupled logic , is a logic family that achieves high speed by using an overdriven BJT differential amplifier with single-ended input, whose emitter current is limited to avoid the slow saturation region of transistor operation....
-based VAX, and two other ECL-based VAXen: "Argonaut" and "Raven". A VAX known as "Gemini" was also cancelled, which was a fall-back in case the LSI-based Scorpio failed. It never shipped.
Clones
- Systime Ltd. of the United KingdomUnited KingdomThe United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
produced clones of early VAX models such as the Systime 8750 (equivalent to the VAX 11/750). - Norden Systems produced the ruggedized, Military-specification MIL VAX series.
- The HungarianHungaryHungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
Central Research Institute for Physics (KFKI) produced a series of clones of early VAX models, the TPA-11/540, 560 and 580. - The SM 52/12 from CzechoslovakiaCzechoslovakiaCzechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...
, developed at VUVT ŽilinaŽilinaŽilina is a city in north-western Slovakia, around from the capital Bratislava, close to both the Czech and Polish borders. It is the fourth largest city of Slovakia with a population of approximately 85,000, an important industrial center, the largest city on the Váh river, and the seat of a...
(today SlovakiaSlovakiaThe Slovak Republic is a landlocked state in Central Europe. It has a population of over five million and an area of about . Slovakia is bordered by the Czech Republic and Austria to the west, Poland to the north, Ukraine to the east and Hungary to the south...
) and produced from 1986 at ZVT Banská BystricaBanská BystricaBanská Bystrica is a key city in central Slovakia located on the Hron River in a long and wide valley encircled by the mountain chains of the Low Tatras, the Veľká Fatra, and the Kremnica Mountains. With 81,281 inhabitants, Banská Bystrica is the sixth most populous municipality in Slovakia...
(today SlovakiaSlovakiaThe Slovak Republic is a landlocked state in Central Europe. It has a population of over five million and an area of about . Slovakia is bordered by the Czech Republic and Austria to the west, Poland to the north, Ukraine to the east and Hungary to the south...
). - The East German RobotronRobotronVEB Kombinat Robotron was the biggest East German electronics manufacturer. It was based in Dresden and employed 68,000 people . It produced personal computers, SM EVM minicomputers, the ESER mainframe computers, several computer peripherals as well as home computers, radios and television...
K 1840 (SM 1710) was a clone of the VAX-11/780 and Robotron K 1820Robotron K 1820The K 1820 was a workstation developed in East Germany. Its more exact name was "RVS K 1820" and it's cipher in the SM EVM of the former COMECON countries was "SM 1720"...
(SM 1720) was a copy of the MicroVAX II. - The SM 1700 was a Soviet clone of the VAX-11/750.