Click Here to visit our Sponsor
The History of Computing The Magazine Have Fun there ! Buy goodies to support us
  Mistake ? You have mr info ? Click here !Add Info     Search     Click here use the advanced search engine
Browse console museumBrowse pong museum


ZX81 T-shirts!

see details
ZX Spectrum T-shirts!

see details
Ready prompt T-shirts!

see details
Spiral program T-shirts!

see details
Atari joystick T-shirts!

see details
Arcade cherry T-shirts!

see details
Battle Zone T-shirts!

see details
Vectrex ship T-shirts!

see details
Elite spaceship t-shirt T-shirts!

see details
C64 maze generator T-shirts!

see details
Moon Lander T-shirts!

see details
Atari ST bombs T-shirts!

see details
Competition Pro Joystick T-shirts!

see details
Pak Pak Monster T-shirts!

see details
BASIC code T-shirts!

see details
Vector ship T-shirts!

see details
Pixel adventure T-shirts!

see details
Breakout T-shirts!

see details

N > NORTHSTAR  > Horizon   


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.

Please consider donating your old computer / videogame system to or one of our partners from anywhere in the world (Europe, America, Asia, etc.).


I owned a Northstar Horizon back in the late 1970s. I don''t remember TurboDOS being available for it. I had 3 different OSes NSDOS, CP/M, and MP/M. I also had two 10MB hard drives that I have seen no reference to anywhere as I only see 5MB listed.. It was one of the first computers to offer any type of Hard Drive. Used it to run a BBS for 10 years.

Friday 27th November 2020
George Worley (USA )

North Star S-100 boards. I have several. Email me please

Tuesday 10th December 2019
Brad (US)

I got about a dozen or so North Star boards. I want to sell them and I can’t find them anywhere online accept a person out of country. Can anyone direct me where to sell them and what I should ask? I’m not trying to get rich, I just want to be treated fare. I’m

Tuesday 10th December 2019
Brad (US)


NAME  Horizon
TYPE  Professional Computer
YEAR  1977
KEYBOARD  Serial terminal
CPU  Zilog Z80
RAM  16 KB (up to 64 KB)
VRAM  Unknown
TEXT MODES  80 chars. x 24 lines
GRAPHIC MODES  Text mode only
COLORS  Monochrome
SOUND  No sound
SIZE / WEIGHT  50.8 (W) x 44.4 (D) x 18.4 (H) cm / About 20 kg
I/O PORTS  12-slot S100 BUS, Serial and Parallel ports
BUILT IN MEDIA  One or Two 5.25'' FDD. Later 5 and 18 MB Hard disk drives, 13.4 MB tape backup
OS  Northstar DOS
POWER SUPPLY  Integrated 250W P.S.U.
PERIPHERALS  S-100 Bus cards
PRICE  Horizon-1: $1599 (kit) $1899 (assembled)
Horizon-2: $1999 (kit) $2349 (assembled)

Please buy a t-shirt to support us !
Ready prompt
ZX Spectrum
Arcade cherry
Spiral program
Atari joystick
Battle Zone
Vectrex ship
C64 maze generator
Moon Lander
Competition Pro Joystick
Atari ST bombs
Elite spaceship t-shirt
Commodore 64 prompt
Pak Pak Monster
Pixel Deer
BASIC code
Shooting gallery
3D Cubes
Pixel adventure
Vector ship

Related Ebay auctions in real time - click to buy yours

see more Northstar  Horizon Ebay auctions !

Click here to go to the top of the page   
Contact us | members | about | donate old-systems | FAQ
OLD-COMPUTERS.COM is hosted by - NYI (New York Internet) -