The Horizon was a S-100 bus based system. It was the first floppy-disc based system hobbyists could buy. In a case with a choice of wood or blue metal cover, the basic version included a 4 Mhz. Z80 microprocessor, 16 KB of RAM, a 90 KB 5''1/4 floppy drive with a controller card, a serial terminal interface and 12 S-100 slots. It was sold with the North Star Disc Operating System and a Basic interpreter allowing random and sequential disk files. The Horizon-2 version offered a second floppy-disc drive.
Any S-100 cards (compatible with Altair, Cromemco and many other systems) could be added to the system, but North Star provided its own additional 16 KB RAM and hardware floating point boards.
In 1979, original 90 KB floppy drives were replaced by Shugart 360 KB models. Northstar also offered an add-on box with two additional floppies, making a total of 4. The box had a matching walnut stained plywood cover.
More information from Jim who worked for NorthStar from 1979:
The Horizon, Aaaahh.. What a beautiful machine. It had a big honkin' trasformer for a linear power supply. It was the first product incorporating its own disk controller (see below), a 4 Mhz 8080, 4 KB of RAM standard, and 1 or 2 Shugart 5.25" floppies. RAM could be expanded to 16 Kb.
The Horizon evolved with a faster (8 Mhz) Zilog Z80, and 64 KB of RAM. Then there was an accounting system called TSS/A that made the Horizon multi-user. It consisted of the main processor board, with multiple memory cards in the bus, and an 8 port I/O card for the other terminals.
The final crowning glory of the Horizon was a multi-user sytem called Turbo-Dos. This used the original processor as a controller, and auxiliary processor boards were added in for each user. They were called 8/16, because they could run at 8 or 16 bits. Each user had their own processor and memory (64K) and connected via boardlets from the main machine.
Another intersting fact - NorthStar was one of the early adopters of the hard disk drive. It was called the HD-18 - 18 Megabytes in an 18 inch platter. The drive was as big as a very large suitcase, and weighed about 70 pounds! You could daisy chain up to 4 of these, but the starting current was 13 amps, and when you lit them up all the lights in the place would dim.
NorthStar's first product was a disk controller for the S-100 bus, namely for Altairs. It controlled Shugart 5-1/4" drives, but using a proprietary format of 10 sectors hard-sectored floppies. This meant that the floppies needed 11 holes near the center, (1 index, and 10 sector markers) which was not the norm. Most floppies had one index hole
Richard Randalll sdpecifies:
I belive North Star's first product was an S-100 board that provided a floating-point processor, rather than the micro-disk subsystem, which followed shortly thereafter.