Acorn Computers Ltd. (Cambridge, UK)

Acorn would become one of England’s and Europe’s leading PC makers. Its earliest computers in the late 1970s were single-board trainers and Eurocard-based rack-mount systems designed for industrial and scientific applications. The System 3, for example, was an enhanced version of Acorn’s 6502-driven System 1 computer trainer with a floppy disk drive and greater memory capacity in a desktop enclosure. A larger System 4 offered 14 slots and dual floppy drives, and the System 5 improved on the performance of the earlier versions.

Those early systems led to Acorn’s first consumer-oriented computer, the Atom. It had better graphics capability than many of its competitors, and the Atom enjoyed a good production run until 1983. The company eventually developed a library of business, productivity, and game software for the Atom. Few were sold in the U.S., and although they are collected domestically, Atoms are more popular today in Europe.
In the early 1980s, Acorn had a U.S. subsidiary based in Massachusetts that sold to the North American market. The first system it sold was Acorn’s BBC Microcomputer. The BBC got its name from the British Broadcasting Corporation, from which Acorn won the right to produce the system in a bidding process. The BBC wanted a computer that participants in it TV-based Open University could use. For a low-cost computer, the BBC was unusual in that it was a multi-processor system; you could have in essence two computers that share common resources running in the same box.
Acorn sold the BBC in two versions: The Model A came standard with 16K RAM, while the Model B had 32K RAM,  better text and graphics capabilities, and RS-423, parallel, RGB, and I/O ports.
Clearly, the Model B is the more desireable machine, and some were sold configured for the North American market starting in 1983. Acorn briefly offered a Model B+ in 1984 shortly before launching the BBC Master. The Model B+ had 64K RAM and a double-density floppy disk drive. Brits referred to the BBC as the “Beeb.”
The BBC Master replaced the BBC Model B in Acorn’s line in 1986. The series also included the BBC Master Turbo, which had a second 65C02 running at 4MHz, and the floppy-disk-based BBC Master 512, which had an 80186 coprocessor and 512K RAM. A Master Compact had similar specification in a smaller design.
In 1983, Acorn decided it needed an entry-level system and introduced the Electron. It wasn’t much computer in its base configuration, but owners could buy expansion upgrades to achieve a system comparable to the BBC Model B, on which the Electron’s design was based. Fully expanded and well-preserved Electrons bring a premium price especially in the U.K.
While Acorn was getting a foothold in the consumer computer market, it hadn’t forgotten the business user. Its Business Computer series, introduced in 1984, included seven models plus a terminal configuration. The Model PA (Personal Assistant) was the base configuration. Models 100 and 110 had a Z80 coprocessor running CP/M. Models 200 and 210 used a 32016 coprocessor running Xenix, and Models 300 and 310 used an 80286 coprocessor running CP/M, MS-DOS, or PC-DOS. The Business Computer internals were based on the BBC Model B+, and examples are scarce today.
Perhaps what Acorn is best known for today is not its computers, but its ARM series of RISC-based microprocessors. Acorn skipped straight from the 8-bit 6502 processors to the 32-bit ARM 2 CPU, which it developed, with the Archimedes line. In the process, the company leapfrogged many of its competitors in terms of pure processing power. The two models in the series were the Archimedes 305 with 512K RAM standard and the Archimedes 310 with 1MB RAM standard. A professional-class Archimedes 400 series was much like the 300, but with two more expansion slots and Acorn’s Econet networking capability built in. It also had hard drive options and greater memory capacity.
Model: Acorn System 3 (1979, early micro)
Base Configuration: 6502 CPU, DOS in ROM, four Eurocard slots, 8K RAM (32K max), 5.25-inch floppy disk drive, video and keyboard interfaces, BASIC in ROMModel: Acorn System 5 (1979, early micro)
Base Configuration: 2MHz 6502 CPU, seven Eurocard slots, 32K RAM, 5.25-inch floppy disk drive, video and keyboard interfaces
Important Options: Versatile Interface card, Econet Interface card, ASCII keyboard, monochrome or color monitor, second floppy drive

Model: Acorn Atom (1979, home computer)
Original Retail Price: £120 to £200 kit, £150 to £250 assembled
Base Configuration: 1MHz 6502A CPU; CUTS cassette routines; Eurocard slot; 2K RAM (40K max), 8K ROM (16K max); integral keyboard; serial, parallel, and PAL TV ports; Atom BASIC and assembler; manual; AC adapter; three-voice sound Video: 256 x 192 graphics Size/Weight: 15 x 9.5 x 2.5 inches
Important Options: DOS, 5.25-inch floppy disk drive, cassette recorder, color graphics card, word processor, GP-80 printer, Econet network interface

Model: Acorn BBC Microcomputer System Model A/Model B (Nov. 1981, desktop micro)
Original Retail Price: £299 to £399
Base Configuration: 2MHz 6502 CPU, MOS (Machine Operating System), extension bus, 16K or 32K RAM per CPU (64K max), 16K ROM, IEEE-488 and PAL TV interfaces, integral keyboard, BBC BASIC in ROM, user guide
Video: 32-line x 40-column text, 320 x 256 graphics (Model A)/32-line x 80-column text, 640 x 256 graphics (Model B)
Size/Weight: 16 x 13.5 x 2.5 inches
Important Options: 6502 or Z80 coprocessor, CP/M 2.2, cassette recorder, 5.25-inch floppy disk drive, monochrome or color CRT display, game paddles, Videotext terminal, Econet network interface, voice synthesizer

Model: Acorn BBC Master 128/BBC Master Turbo/BBC Master 512 (Jan. 1986, home computer)
Base Configuration: 2MHz 65C02 CPU, 4MHz 65C02 coprocessor (BBC Master Turbo)/8MHz 80186 coprocessor (BBC Master 512), ADFS, 128K RAM (512K max), 64K ROM, floppy disk drive (BBC Master 512)

Model: Acorn Electron (Aug. 1983, home computer)
Base Configuration: 2MHz 6502 CPU; 32K RAM; 32K ROM; RGB, composite, and TV video ports; integral keyboard; game and cassette ports
Video: 32-line x 80 column text, 640 x 256 graphics, eight colors
Important Options: external 3.5-inch floppy disk drive, RS-232 and parallel interfaces, EPROM programmer

Model: Acorn Business Computer Series (1984, desktop)
Base Configuration: 2MHz 6502 CPU, operating system in ROM, 64K RAM (4MB max)
Important Options: Z80, 32016, 80186, or 80286 coprocessor; CP/M, Xenix, MS-DOS, or PC-DOS; 10MB hard disk drive

Model: Acorn Archimedes A300 Series (1987, desktop)
Base Configuration: ARM 2 CPU, Arthur operating system and ADFS, two expansion slots, 512K RAM (1MB max), 512K ROM
Video: 640 x 512 graphics, 256 colors


1979- Acorn computer catalog
1979- acorn atom brochure

1982 acorn bbc microcomputer system brochure

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