Acorn ABC100
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| Acorn's brochure photograph of the ABC; all models share this case and keyboard | |
| Specifications | |
|---|---|
| Manufacturer | Acorn Computers |
| Type | Business computer (not released) |
| Intro price | £1,599 + VAT (announced)[1] |
| CPU | Z80 second processor; 6502-family I/O processor |
| Memory | 64 KB (Z80) |
| Storage | Two 5.25-inch floppy drives (720 KB each) |
| Display | Built-in 12-inch green monochrome monitor |
| Sound | — |
| OS / Firmware | CP/M |
| Model no. | ABC 100 |
The Acorn ABC 100 is the CP/M model of the Acorn Business Computer (ABC) range: Acorn's Z80 second processor packaged with a BBC B+ based main board, two 5.25-inch floppy drives and a green screen in the ABC's combined monitor and system case.[2] The range was cancelled before it went on sale, and Chris Whytehead, whose collection holds the ABC 110, had not found an ABC 100.[2] The ABC 110 is the same machine with one floppy drive replaced by a 10 MB hard disc and a colour screen.[2]
History
[edit | edit source]Acorn's agreement with the BBC included a business upgrade for the BBC Micro, which became the Z80 second processor. Wikipedia records that the machine that became the ABC 100 was described in mid-1983 as the Acorn Business Machine: a BBC Micro with the Z80 second processor, twin disc drives and CP/M.[1] Accounts of the launch differ. Chris Whytehead says the range was launched at the end of 1983 with the first models available in early 1984;[2] Acorn User reported in October 1984 that the machines should be on view at dealers in November, with deliveries from the new year;[3] and Wikipedia gives a demonstration at the PCW Show in September 1984 and a launch scheduled for January 1985, followed by cancellation after Olivetti's rescue of Acorn.[1]
Specification
[edit | edit source]Acorn's brochure lists the ABC 100 with a Z80 main processor, twin 720 KB disc drives, Econet, the CP/M operating system and the MemoPlan, FilePlan, MicroPlan and GraphPlan programs.[4] The main ABC board continues to handle the keyboard, screen and communications, with the Z80 running the programs.[4] Acorn User gave the drives as 700 KB each.[3]
The Z80 card fitted to the ABC range is the same card as in Acorn's Z80 second processor; in Chris Whytehead's ABC 110 it is board 209,000 issue 2 with a Mostek Z80 at 6 MHz and 64 KB of RAM.[5]
Construction and service
[edit | edit source]The ABC 100 uses the common ABC case: the monitor, drives and electronics in one unit on a tilt-and-swivel stand with a separate keyboard, the processor card in a side wing and the main board under a monitor chassis that hinges up.[4][6] The construction, the Tube switch on the keyboard and the related Acorn service documents are described on Acorn ABC110#Construction.
Warning: the monitor electronics inside the case are uncased and hold a high voltage after switch-off.[6] See CRT Discharge Procedure.
No ABC 100 service manual is known. For the parts it shares with other Acorn products, see Acorn Business Computer Documentation.
Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 1.2 "Acorn Business Computer", Wikipedia (retrieved 2026-10-01). Range announced in late 1983, shown at the PCW Show in September 1984, launch scheduled for January 1985, cancelled before any models shipped; the ABC 100 described in mid-1983 as the Acorn Business Machine; announced prices including ABC 100 £1,599 + VAT.
- ↑ 2.0 2.1 2.2 2.3 Whytehead, Chris. "Acorn Business Computer", Chris's Acorns, The Centre for Computing History (retrieved 2026-10-01). Range history and cancellation; ABC 100: twin 5.25-inch floppy drives, BBC Micro Z80 second processor in the ABC case, MemoPlan, FilePlan, MicroPlan and GraphPlan, green screen; listed as wanted; most models said to have been rebuilt as ACWs; with the Tube switched off the machines work as BBC B+ computers.
- ↑ 3.0 3.1 "New Acorn micro", Acorn User, October 1984, pp. 7 and 9. Scan via Chris's Acorns. Eight variants under the ABC name; the ABC 100 with the Z80 second processor, CP/M, two 700 KB drives and the three Plan packages; a 12-inch monitor; the 32016 models with 256 KB as standard; a monitor that tips forward to give access to internal sockets.
- ↑ 4.0 4.1 4.2 Acorn Computers, brochure "The Acorn Business Computer", APP01. Hosted on this wiki: File:Acorn Business Computer brochure (APP01).pdf. Pages 1 and 2 (range, 12-inch tilt-and-swivel monitor, keyboard with numeric pad and ten function keys, ABC 100 description) and page 4 (model specifications).
- ↑ Whytehead, Chris. "Acorn Business Computer ABC110", Chris's Acorns (retrieved 2026-10-01).
- ↑ 6.0 6.1 "Acorn ABC 310", Personal Computer World, vol. 8 no. 4, April 1985. Scan via Chris's Acorns. Side wings released by four quick-release studs, monitor chassis by two more; uncased monitor electronics holding a high voltage after switch-off; keyboard reset button and Tube switch.