NorthStar Horizon

Horizon

A NorthStar Horizon computer
Manufacturer	NorthStar Computers
Type	Personal Computer
Release date	November 1977 (1977-11)
Introductory price	$1899 Assembled $1599 as a Kit
Discontinued	Early 1980's
Units sold	10,000-100,000+
Operating system	CP/M, NorthStar DOS
CPU	Z-80 @ 4MHz
Memory	16K or more
Storage	5.25 floppy drive(s) holds 90KB each
Display	Monochrome
Graphics	Text Mode only
Sound	None
Power	Integrated 250W P.S.U.
Dimensions	50.8 x 44.4 x 18.4 cm
Weight	20 kg
Successor	NorthStar Advantage

The NorthStar Horizon was a popular 8-bit S-100 bus computer introduced in October 1977. Like most S-100 machines of the era, it was built around the ZiLOG Z80A microprocessor, and typically ran the CP/M operating system. It was produced by North Star Computers, and it could be purchased either in kit form or pre-assembled.^[1] The NorthStar Horizon was one of the first computers to have built in floppy drives ^[2] as well as being one of the first computers to have a hard disk drive.^[3]

A Z80 processor board for the NorthStar Horizon

An inside view of the NorthStar Horizon

Specifications

The computer consists of a thick aluminium chassis separated into left and right compartments with a plywood cover which sat on the top and draped over the left and right sides. The rear section of the compartment on the right held a linear power supply, including a large transformer and power capacitors, comprising much of the bulk and weight of the system. The empty section in front of the power supply normally housed one or two floppy disk drives, placed on their side so the slots were vertical. The compartment on the left held the S-100 motherboard, rotated so the slots ran left-right. Although a few logic circuits were on the motherboard, primarily for I/O functions, both the processor and the memory resided in separate daughterboards.

Capable of running CP/M and NSDOS (NorthStar's proprietary Disk Operating System), a standard NorthStar system sported one or two hard-sectored 5.25 inch floppy disk drives and a serial interface to which one could connect a terminal to interact with it. NSDOS included NorthStar BASIC, a slightly non-standard dialect of BASIC, where some standard BASIC commands of the day had been changed, probably to avoid potential legal issues. Two examples of this were the FILL and EXAM commands, which took the place of the more common PEEK and POKE.

The Horizon was superseded by the all-in-one NorthStar Advantage in 1982.^[4] The Horizon found a niche in University environments where its inbuilt S-100 bus could be used to interface it to a variety of control systems.^[5]

Northstar released a Hard disk version, with an internal full height 5MB MFM drive. They also released a S100 card with integrated memory and two serial ports which allowed up to eight users on one Horizon, each with their own CPU sharing the disk and other resources. This operated under TurboDOS, a multi user CP/M variant with some unix like features.

Interesting facts

• NorthStar started out in 1976 as a computer store called "The Original Kentucky Fried Computers" which they promptly changed due to litigation from Kentucky Fried Chicken.^[2][3]
• The NorthStar Horizon is one of only a handful of computers to be sold in a wooden cabinet. Later versions featured an all-metal case which met safety standards.^[2]

References

External links

• NorthStar Horizon at Obsolete Technology
• NorthStar Horizon at Old Computer Museum
• North Star Computers Manuals from Harte Technologies
• NorthStar documentation from Rich's classic computing lab