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G > GEMINI  > Challenger   


Before the Challenger came out, Gemini products were based around the Z80 processor and the company's 80-bus architecture. They did well in applications where costumers wanted a highly-specialized product.

At first sight, the Challenger looked like an ordinary PC-compatible computer. The monitor was a Wyse WY-50 remote terminal finished as the same colours as the main box. However, the Challenger's main processor was a 12 MHz Motorola 68000 linked with 512 KB of RAM. This configuration made the Challenger a very high speed 16-bit system for the time.

While designing the Challenger, Gemini designers also created a new 68000 proprietary bus called 68K, which was originally a 16-bit bus but was later extended to 32-bit when the 68020 became available. Four 68K slots were available on the Challenger mainboard. They also designed an impressive graphic card based on the Hitachi HD63484 graphic processor and consisting in two piggy-back full length cards plugged into a 68K slot. Maximum resolution was 1024 x 1024 pixels with 16 million available colours.

The Challenger was delivered with a wide range of operating systems:
- MBOS a business-based multi-user O.S.,
- Mirage Another multi-user O.S. but more esoteric,
- TDI p-System, the British version of UCSD p-System well known for its UCSD Pascal language,
- CP/M 68k, the 68000 version of the 8-bit O.S. which was never very popular.
Each of these O.S. could cohabit into several partitions of a same hard disk.

Despite it's advanced features, the Challenger never met success, neither as a businness machine as very few software were developped for it, nor as a development system as the 68K bus never was carried by other manufacturers.

The last machine made by Gemini was a beautifully built IBM clone using a motherboard designed by British Aerospace. But it was too expensive and couldn't compete against far east production. Gemini finally disappeared about one year after the Challenger was launched.

We need more info about this computer ! If you designed, used, or have more info about this system, please send us pictures or anything you might find useful.
Please consider donating your old computer / videogame system to or one of our partners from anywhere in the world (Europe, America, Asia, etc.).


I wrote a system for VETS on this system under Mirage. A also wrote a virtual terminal system which allowed multiple sessions on each terminal (Much like ALT+Fn keys in linux). It worked well, but operating system support was a bit of a problem sometimes. I also wrote SCSI drivers for Mirage to allow for an external SCSI drive.

Monday 7th May 2012
John B Hanson (UK/West Sussex)
Coastline Computer Consultancy

I worked at T.D.I in Bristol in the early 80''s and ported the UCSD p-system to this machine. It was my favorite machine at the time, beautiful spec, construction, but sadly we never made a multi-user version. The graphics chip was great fun to program for (did the Turtle Graphics for UCSD as well). Always sad that this one wasn''t a success ...
(but it couldn''t compete with the Stride/Pinnacle machines)

Tuesday 27th December 2011
Andy Allen (Greece)

I remember the Mirage OS slightly. It had a very VAX/VMS-like user interface, not sure about the internals - and was used quite a bit for soft-realtime in process control industries in the UK.

It also appeared on a number of other 68k-based machines.

Thursday 24th April 2003
Pete Fenelon (UK)


NAME  Challenger
TYPE  Professional Computer
ORIGIN  United Kingdom
YEAR  1985
KEYBOARD  Full stroke 101-key with numeric keypad and 16 function keys
CPU  Motorola 68000
RAM  512 KB
ROM  16 KB
TEXT MODES  80 or 132 chars. x 25 lines
GRAPHIC MODES  768 x 576 - 16 to 16 million col. / 1024 x 1024 - 64 col. with optional video card
COLORS  16 up to 16 million
SOUND  Unknown
SIZE / WEIGHT  19.25 (W) x 16 (D) x 5.75 (H) ins
I/O PORTS  SCSI, Parallel, 2 x Serial RS232, 4 x 68K expansion slots
BUILT IN MEDIA  1 x 5.25'' 1.2 MB floppy disc drive, Hard disks from 20 to 70 MB
OS  MBOS, Mirage, TDI P-system, CP/M 68k
POWER SUPPLY  Built-in 100Watt switching power supply unit
PERIPHERALS  SCSI peripherals, 68K bus cards
PRICE  From £4750 to £9500

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