Home‎ > ‎Small Systems Collection‎ > ‎

North Star Horizon #2

Serial Number 10-00131, a gift of Michael Barndt.

The Horizon was the first computer produced by North Star Computers starting in 1979. In typical Berkeley California fashion the company was originally called Kentucky Fried Computers. Unfortunately the company insisted on using hard-sector floppy diskettes when the rest of the industry was using soft-sector diskettes. This made it very difficult to move files and software between a North Star computer any other. Sales suffered, and the company failed in the Mid-80s.

The backplane in the Horizon is a little unusual. It contains the circuitry for two serial and two parallel ports. The serial ports were for the console terminal and a printer. The parallel ports could be used for printers or disk drives. It contains one Shugart Associates Model 400 hard-sector diskette drive, with room for a second.

Click on the image for a larger view.
North Star ZPB-A1 Z-80 Processor Board
The PROM Monitor option is not installed
Auto-Jump Address Selection = E800

Click on the image for a larger view.
North Star MDC-A4 Single-Density Micro-Disk Controller
Boot ROM @E800

Click on the image for a larger view.
Godbout Econoram VII, 24k x 8 static RAM
4k@8000-8FFF, 4k@9000-9FFF, 8k@A000-BFFF, 8k@C000-DFFF

Click on the image for a larger view.
Cromemco TU_ART
Device A =A0, Device B=90

Click on the image for a larger view.
North Star RAM16-A2 16k RAM
16k@4000-7FFF

Click on the image for a larger view.
Micromation Doubler, Double-Density 8" Diskette Controller

Click on the image for a larger view.
Godbout Econoram IV, 16k x 8 static RAM
16k@0000-3FFF


Click on the image for a larger view.
The North Star Horizon with the wooden cover removed.


Click on the image for a larger view.
Notice the circuitry on the rear of the backplane.
A Shugart Associated SA-400 Diskette Drive is installed at the right.

The boards from front to back:
North Star ZPB-A1 Z-80 Processor Board
North Star MDC-A4 Single-Density Micro-Disk Controller
Godbout Econoram VII, 24k RAM@8000
Cromemco TU_ART, two serial, two parallel
North Star RAM 16-A2, 16k RAM@4000
Micromation Doubler, Double-Density 8" Diskette Controller
Godbout Econoram IV, 16k RAM@0000

Click on the image for a larger view.
A close-up of the circuitry on the rear of the backplane.
Ports start at address 00.
The serial ports are configured for 9600 baud.
The left serial is configured for:
9600 baud
Connect to a terminal, but the header at 3D should have pin 1 connected to pin 12, not 13.
The right serial is not implemented.
The parallel port is configured for:
Output enable control grounded
Output Acknowledge signal tied to clock of the parallel output interface flag flip-flop
HIGH while valid data on bus tied to 7 of the parallel output interface connector
The Real Time Clock is not enabled.
The Interrupt configuration is at the factory defaults, not enabled.
Comments