 Cromemco Z-2 CPU unit and terminal | |
| Developer | Cromemco |
|---|---|
| Type | Microcomputer |
| Release date | 1977 |
| Operating system | CP/M, Cromemco DOS |
| CPU | Zilog Z80 |
Z-2 is a series of microcomputers made by Cromemco, Inc. which were introduced to the market in the middle to late 1970s. They were S-100 bus machines powered by the Zilog Z80 processor and typically ran on the CP/M operating system.
They were originally available in assembled or kit form to serve both a commercial market and the computer enthusiast market. Later the machines were only available factory-assembled. The machines were widely respected for their speed, configurability, durability, and reliability.[1][2][3][4]
The Z-2 was a Z80–based microcomputer system that was introduced in 1977. The original Z-2 in kit form included a ZPU-K Z80 CPU card, S-100 bus motherboard, all-metal rack-mount chassis and dust case, card socket and card guide; the assembled form included a complete set of sockets and card guides, and a cooling fan. The Z-2 series was capable of supporting up to 21 S-100 boards and could be configured with any of the boards supplied by Cromemco.[5]
The Z-2 gave an impression of solidity due to its hefty 450-watt power supply and heavy metal chassis. A TU-ART (dual serial and parallel board), 4FDC Floppy Disk Controller, one or more 16KZRAM cards, and a Wangco 5¼" floppy disk drive would be added to form a basic system.
An unusual feature of the Z-2 was switch–selectable CPU speed; 250 or 500 nanosecond cycle time were available. The ZPU speed was 4 MHz at a time when less than 2 MHz was normal, and boards from other manufacturers might still require the slower speed. The ZPU card in the Z-2 could address up to 64 kilobytes (65,536 bytes) of RAM. However, the 16KZ memory card supported bank-switching with 8 banks of 64 kilobytes each. When using the 16KZ, the maximum RAM of the Z-2 was limited by the available S-100 slots. If 16 of the slots were occupied by 16KZ cards, then the system had 4 banks of 64 kilobytes each, for a total of 256 kilobytes (262,144 bytes).
Additional S-100 slots were required for cards controlling peripherals, disk drives, and I/O interfaces. Communication with the processor was normally performed through a TU-ART or other S-100 bus compatible interface card, which could run a CRT terminal or teletype.
- ^ Veit, Stan (1993). "Cromemco: Innovation and Reliability". Stan Veit's History of the Personal Computer. Asheville, North Carolina: WorldComm. pp. 103–112. ISBN 1-56664-023-7.
It was said that circus elephants could stand on the Z-2 without damaging it.
- ^ The Association of Computer Users (April 1980). "Cromemco's System Two and Z-2H". Benchmark Report. 3.1 (4).
- ^ Warren, Jim (7 February 1979). "Report on Outstanding Cromemco Reliability". Intelligent Machines Journal (2): 4.
- ^ Stevens, Richard (February 1979). "Cromemco Z-2D under the microscope: Construction never less than excellent". Practical Computing. 2 (2). Retrieved 3 March 2013.
- ^ Cromemco Z-2 Instruction Manual, Cromemco, Inc. Part No. N/A, 1977