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The Z8000 was a 16-bit
16-bit

16-bit architectureThe HP 2100#Descendants and variants , 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....
 microprocessor
Microprocessor

A microprocessor incorporates most or all of the functions of a central processing unit on a single integrated circuit . The first microprocessors emerged in the early 1970s and were used for electronic calculators, using Binary-coded decimal arithmetic on 4-bit Word ....
 introduced by ZiLOG
Zilog

Zilog, Inc., often seen as ZiLOG , is a manufacturer of 8-bit, 16-bit, 24-bit, and 32-bit microprocessors, and is most famous for its Intel 8080-compatible Zilog Z80 series....
 in 1979. The architecture was designed by Bernard Peuto while the logic and physical implementation was done by Masatoshi Shima
Masatoshi Shima

Masatoshi Shima was one of the designers of the world's first microprocessor, the Intel 4004, along with Marcian Hoff, Stanley Mazor, and Federico Faggin....
, assisted by a small group of people. Z8000 was not Z80
Zilog Z80

The Zilog Z80 is an 8-bit microprocessor designed and sold by Zilog from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes....
-compatible, and although it saw steady use well into the 1990s, it was not very widely used. However, the Z16C01 and Z16C02 Serial Communication Controllers still use the Z8000 core.

ough fundamentally a 16-bit architecture
Architecture

The term architecture can refer to a process, a profession or documentation.As a process, architecture is the activity of designing and construction buildings and other physical structures by a person or a computer, primarily to provide shelter....
, some versions had 7-bit, segment registers that extended the address space to 8 megabytes.

The register set
Processor register

In computer architecture, a processor register is a small amount of Computer storage available on the CPU whose contents can be accessed more quickly than storage available elsewhere....
 consisted of sixteen 16-bit registers, and there were instructions that could use them as 8-bit
8-bit

Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their address space is limited to 64 KBs. This is not a "natural law", however, so there are exceptions....
, 16-bit, 32-bit
32-bit

The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295 or -2,147,483,648 through 2,147,483,647 using two's complement encoding....
, and 64-bit
64-bit

64-bit CPUs have existed in supercomputers since the 1960s and in RISC-based computer workstation and Server s since the early 1990s. In 2003 they were introduced to the mainstream personal computer arena, in the form of the x86-64 and 64-bit PowerPC processor architectures....
 registers.






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The Z8000 was a 16-bit
16-bit

16-bit architectureThe HP 2100#Descendants and variants , 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....
 microprocessor
Microprocessor

A microprocessor incorporates most or all of the functions of a central processing unit on a single integrated circuit . The first microprocessors emerged in the early 1970s and were used for electronic calculators, using Binary-coded decimal arithmetic on 4-bit Word ....
 introduced by ZiLOG
Zilog

Zilog, Inc., often seen as ZiLOG , is a manufacturer of 8-bit, 16-bit, 24-bit, and 32-bit microprocessors, and is most famous for its Intel 8080-compatible Zilog Z80 series....
 in 1979. The architecture was designed by Bernard Peuto while the logic and physical implementation was done by Masatoshi Shima
Masatoshi Shima

Masatoshi Shima was one of the designers of the world's first microprocessor, the Intel 4004, along with Marcian Hoff, Stanley Mazor, and Federico Faggin....
, assisted by a small group of people. Z8000 was not Z80
Zilog Z80

The Zilog Z80 is an 8-bit microprocessor designed and sold by Zilog from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes....
-compatible, and although it saw steady use well into the 1990s, it was not very widely used. However, the Z16C01 and Z16C02 Serial Communication Controllers still use the Z8000 core.

Feature

Although fundamentally a 16-bit architecture
Architecture

The term architecture can refer to a process, a profession or documentation.As a process, architecture is the activity of designing and construction buildings and other physical structures by a person or a computer, primarily to provide shelter....
, some versions had 7-bit, segment registers that extended the address space to 8 megabytes.

The register set
Processor register

In computer architecture, a processor register is a small amount of Computer storage available on the CPU whose contents can be accessed more quickly than storage available elsewhere....
 consisted of sixteen 16-bit registers, and there were instructions that could use them as 8-bit
8-bit

Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their address space is limited to 64 KBs. This is not a "natural law", however, so there are exceptions....
, 16-bit, 32-bit
32-bit

The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295 or -2,147,483,648 through 2,147,483,647 using two's complement encoding....
, and 64-bit
64-bit

64-bit CPUs have existed in supercomputers since the 1960s and in RISC-based computer workstation and Server s since the early 1990s. In 2003 they were introduced to the mainstream personal computer arena, in the form of the x86-64 and 64-bit PowerPC processor architectures....
 registers. The register set was completely orthogonal, with register 15 conventionally designated as stack
Stack (data structure)

In computer science, a stack is an abstract data type and data structure based on the principle of LIFO . Stacks are used extensively at every level of a modern computer system....
 pointer, and register 14 for stack segment.

There was both a user mode and a supervisor mode.

Like the Z80, the Z8000 included built-in DRAM
Dram

Dram or DRAM may refer to:* Dram , an imperial unit of mass and volume* Armenian dram, a monetary unit* Dynamic random access memory* Database of Recorded American Music...
 refresh circuitry. Although an attractive feature for designers of the time, overall the Z8000 was not especially fast and had some bugs, and in the end it was overshadowed by the x86 family.

One notable use of the Z8000 series was by Namco
Namco

, from NAkamura Manufacturing COmpany, is an amusement company based in Japan, best known overseas for video games development. On September 29 2005, Namco officially merged with Japanese toymaker Bandai to form Namco Bandai, one of the largest entertainment companies in Japan.Namco became a wholly owned subsidiary of the holdin...
 in the design of its famous Pole Position
Pole Position

Pole Position is a racing game video game released in 1982 by Namco. In this game, the player has to complete a lap in a certain amount of time in order to qualify for an Formula One race at the Fuji Speedway....
 series of racing videogames. Two Z8002's (small-memory versions of the Z8000) were incorporated into the design.

The reported inclusion of the device within military
Military

A military is an organization authorized by its nation to use force, usually including use of weapons, in defending its country by combating actual or Threat of force ....
 designs (source:TechWeb ), perhaps provides an explanation for the continued survival of the Z8000 today, in the shape of the Z16C01/02 Serial Communication Controllers (Zilog SCC
Zilog SCC

The Zilog Serial Communications Controller or Zilog SCC was introduced in the early 1980s and provided the ability to do both standard UART style serial communications along with the HDLC protocol for a reasonable price....
). Indeed, an active order code and datasheet may still be located upon the ZiLOG website.

The Zilog Z80000
Zilog Z80000

The Z80000 was Zilog's 32-bit central processing unit from 1986, an expansion of its 16-bit predecessor, the Zilog Z8000. It included multiprocessing capability, a six-stage instruction pipeline, and a 256-byte cache....
 was a 32-bit follow-on design.

Z8000 CPU based systems


In the early 1980s, the Zilog Z8000 CPU was popular for desktop sized Unix machines. They allowed small businesses to run a true multi-user system and share resources (disk, printers) before networking was common. They usually had only RS232 serial ports (4-16) and parallel printer ports instead of built in graphics, as was typical for servers of the time.

Z8000-based computer systems included Zilog's own System 8000 series, as well as other manufacturers:
  • Jan 1980: Z8000 ONYX, 1st Unix workstation, demoed (8 serial ports [users], $25k) (source:)
  • other Z8000-based computer systems: Olivetti M20, M30, M40, M50, M60. (source:)
  • The Z8000 can be found in some rare but well-known computers though, such as the Olivetti M20 and M40, and the Unix-based Commodore 900. Some third parties also manufactured the Z8000 including AMD, Hitachi and Sharp (source:)


There was a Z8000 version of the Xenix Operating System (source:)

The Z8000 CPU series was introduced in early 1979, between the launch of the Intel 8086 (April 1978) and the Motorola 68000 (September 1979) (source: ). That explains timeframe and why the Z8000 CPU-based systems lost their dominance to Motorola 68000 based machines, then to the Intel 80286.

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