Cromenco System Three
[Vin4]
The Cromemco System Three, introduced in 1979, was a high-end, rack-mounted microcomputer featuring a robust S-100 bus architecture with a 21-slot motherboard, allowing substantial expansion. It ran a Z-80A CPU at 4 MHz, with some models optionally including a Motorola 68000, supporting multi-user operation via the UNIX-like CROMIX OS. Its memory expandable up to 4 MB, dual 8-inch floppy drives, and professional usage made it popular in military and broadcast environments. Notably, the System Three supported the Cromemco Dazzler, introduced in 1976, the world’s first colour graphics card for microcomputers. The Dazzler produced composite NTSC video output, enabling color displays on TVs and monitors, which was groundbreaking at the time and helped drive Cromemco systems into television broadcast and other graphical applications.
- Manufacturer: Cromenco Inc.
- Type: Rack-mount microcomputer
- Release Date: 1979
- Cost at release: USD $5,990 (CAD ~$28,000 adjusted for inflation)
- Cost with peripherals: USD $12,495 (CAD ~$59,000 adjusted for inflation)
- MIPS: 0.58-0.8 (580 – 800 KIPS)
- Hardware Specifications
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- CPU: Z-80A @ 4MHz, dual-processor option (Z-80A and Motorola 68000)
- RAM: 64K – 512K
- Storage: Dual 8-inch floppy disk drives
- Display: Text on RS-232 terminal
- Ports: 1 parallel for printer
- Operating System & Programming Languages
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- OS: Cromemco CDOS or CROMIX, Cromemco CDOS (CP/M-compatible) and CROMIX (UNIX-like)
- Programming Languages: FORTRAN 77, C, Pascal, COBOL, BASIC, RATFOR, LISP, RPG-I, Macro Assembler
- Notables
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- Cromemco was named after “Crothers Memorial Hall,” the Stanford dorm where the founders began their collaboration
- The System Three was one of the earliest microcomputers to offer true multi-user capabilities, supporting up to six simultaneous users with its UNIX-like CROMIX operating system
- It featured a dual-processor option (Z-80A and Motorola 68000), making it unusually powerful and flexible for its era
- The System Three was not a desktop machine but a heavy, rack-mountable system intended for professional and institutional environments
- Cromemco computers, including the System Three, were widely used by the U.S. military, notably the Air Force and Navy, and were deployed in critical applications such as the Mission Support System for fighter aircraft and on Ohio-class submarines
- The System Three and its siblings were used in the Chicago Mercantile Exchange for trade processing and in over 80% of major U.S. TV stations for weather and news graphics in the 1980s
- Cromemco systems were among the first microcomputers distributed in China, with over 10,000 units sold to universities by 1985
- Its place in computing history is as a pioneering, reliable, and expandable microcomputer that bridged the gap between hobbyist systems and robust business/industrial computing, influencing the evolution of multi-user microcomputers and early UNIX-like systems
Donated by: Dr. Arlen Michaels
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The Cromemco System Three, introduced in 1979, was a high-end, rack-mounted microcomputer featuring a robust S-100 bus architecture with a 21-slot motherboard, allowing substantial expansion. It ran a Z-80A CPU at 4 MHz, with some models optionally including a Motorola 68000, supporting multi-user operation via the UNIX-like CROMIX OS. Its memory expandable up to 4 MB, dual 8-inch floppy drives, and professional usage made it popular in military and broadcast environments. Notably, the System Three supported the Cromemco Dazzler, introduced in 1976, the world’s first colour graphics card for microcomputers. The Dazzler produced composite NTSC video output, enabling color displays on TVs and monitors, which was groundbreaking at the time and helped drive Cromemco systems into television broadcast and other graphical applications.