Zenith Z-100

The Z-100 computer is a personal computer made by Zenith Data Systems. It was a competitor to the IBM PC.

Design

The Zenith Data Systems Z-100 is a pre-assembled version of the Heathkit H100 electronic kit, but unlike the Zenith Z-89 that Heathkit created, the Z-100 was designed first as a preassembled product. Design began in March 1981 for a Z-89 successor with faster processor, improved graphics, support for memory beyond 64K, and more sophisticated operating systems.
In the same family, the Z-120 is an all-in-one model with self-contained monitor, and the Z-110 is similar in size to the cabinet of an IBM PC.Both models have a built-in keyboard that was modeled after the IBM Selectric typewriter.

Dual processors: 8085 and 8088.
Available with CP/M and Z-DOS.
Five S-100 expansion slots.
Two 320 KB 40-track double-sided 5.25-inch floppy disk drives. Socket enabled direct plug-in of external 8-inch floppies.
Two serial ports, one Centronics printer port, light pen port.
640×225 bitmap display, with eight colors, or monochrome upgradable to eight greyscales.
Base 128 KB RAM, expandable to 192 KB on board, to 768 KB with S-100 cards..

Zenith stated that the Z-100 would be compatible with most Intel 8080 and Z-89 software. The computer is partially compatible with the IBM PC, using standard floppy drives. It runs a non-IBM version of MS-DOS, so generic MS-DOS programs run, but most commercial PC software uses IBM BIOS extensions and do not run, including Lotus 1-2-3. Several companies offered software or hardware solutions to permit unmodified PC programs to work on the Z-100.
The Z-100 has unusually good graphics for its era, superior to the contemporary CGA, IBM Monochrome Display Adapter, and with eight colors or grayscales available at a lower resolution than the Hercules Graphics Card. Early versions of AutoCAD were released for the Z-100 because of these advanced graphics.
Aftermarket vendors also released modifications to upgrade mainboard memory and permit installation of an Intel 8087 math coprocessor.

Uses

In 1983, Clarkson College of Technology became the first college in the nation to give each incoming freshman a personal computer. The model issued to them was the Z-100.

Reception

Jerry Pournelle in 1983 praised the Z-100's keyboard, and wrote that it "had the best color graphics I've seen on a small machine". Although forced to buy a real IBM PC because of the Z-100 and other computers' incomplete PC compatibility, he reported in December 1983 that a friend who was inexperienced with electronic kits was able to assemble a Z-100 in a day, with only the disk controller needing soldering. Ken Skier praised the computer's reliability in the magazine in January 1984 after using the computer for more than 40 hours a week for eight months. While criticizing its inability to read other disk formats, he approved of Zenith's technical support, documentation, and keyboard and graphics. Skier concluded that those who "want a well-designed, well-built, well-documented system that runs the best of 8-bit and 16-bit worlds" should "consider the Zenith Z-100". "Simply put", InfoWorld wrote, "this is an excellent machine". Graphics, keyboard, adherence to industry standards, 90-day on-site service, and bundled software were among the features the magazine approved of. While wishing for tutorial documentation, detachable keyboard, and quieter fan, InfoWorld concluded "This is a superb machine".