Acorn Atom

Acorn Computers Ltd. sold the Atom as a personal computer in both kit and assembled forms, with configurations ranging from 2K RAM to 12K RAM and 8K to 12K ROM, priced from £110 for a 2K RAM kit to £174 for a colour-equipped model.

The Atom arrived in multiple configurations, its base model equipped with 8K ROM and 2K RAM, available either as a kit for £110 or assembled for £140¹⁰. A fully built unit with 8K ROM and 2K RAM, paired with the March Communications APS-3 power supply, retailed for £150¹²³⁵. Upgraded models included the FULL MEMORY ATOM with 8K ROM and 12K RAM at £169⁶⁷, or assembled for £160¹⁰. The COLOUR ATOM, featuring a "New Colour Encoder" and 5K RAM, listed at £174⁶⁷, while the equivalent assembled version cost £158¹⁰. A 12K RAM kit sold for £130¹⁰. Advertisements in 1982 cited a starting price of £140 for assembled units⁸⁹.

Expansion was central to the design: the Atom featured a 64-way connector on the rear, enabling interface with Acorn’s Eurocard-based peripherals¹². One such add-on, the Econet Eurocard, plugged directly into the backplane and included ROM with low-level Econet software, allowing networked operation¹¹. The system supported additional ROMs, including a 4K Floating-point ROM, an ATOM Word Pack ROM, and UTILITY ROMs for Extended Basic, Toolchest, and Interface functions⁸⁹. Memory expansion cost £3.20 per 1K⁸⁹. For storage, Acorn offered a disc controller card based on the Intel 8271 chip, containing 4K of DOS ROM and 3K bytes of static RAM, priced at £350 mail order including VAT and insurance¹³. This controller required an Atom equipped with bus buffers and indirect edge connectors¹³.

Use of a joystick required both the Versatile Interface Adaptor (VIA) and the Integer Basic ROM¹²⁴. The New PAL Colour Encoder, sold separately for £38, enabled colour output¹⁰. Power supply options included the March Communications APS-3, a "New 1.8A Power Supply" at £8.40, and an "ACORN ATOM power supply 5volt/5amp" priced at £46¹⁰¹⁴. The system was fully compatible with other Acorn Atom software and hardware, and some ROMs were designed to fit inside the casing alongside expansions like the colour encoder¹. Eurocard rack-mounting variants were also available¹.

Acornsoft, a registered trademark of Acorn Computers Ltd., provided software for the platform, including ATOMTEL, which converted the Atom into a Prestel terminal⁸⁹¹²¹⁶. Four Acorn Software Packs were offered⁴¹⁵, and supporting literature included Getting Acquainted with your Acorn Atom, Atom Business, and Atom Magic Book³⁵⁶⁷. A later title, Practical Programs for the BBC Computer and the Acorn Atom, acknowledged the shared software space between the machines⁶⁷.

The Atom’s legacy is tied to the BBC Micro. Acorn was developing a successor to the Atom, a machine originally codenamed PROTON, which impressed the BBC during their selection process³⁵. The BBC reportedly dropped a requirement for a Z80 CPU to accept Acorn’s 6502-based design³⁵. The resulting BBC Micro, while shaped by institutional demands, owed a significant architectural debt to the Atom³⁵. Acorn themselves cited the Atom as one of their most successful products¹¹, and the company was one of only two approved by both the UK Department of Industry and the Department of Education and Science¹¹.

Warranty terms covered assembled and tested equipment for six months with correct use, and kit components carried the same guarantee¹¹. A fast service facility operated in Cambridge, and repairs were reportedly completed within two weeks by a qualified team¹¹.

References

1. ComputingToday198204 (1982)
2. ComputingToday198204 (1982)
3. ComputingToday198203 (1982)
4. ComputingToday198206 (1982)
5. ComputingToday198203 (1982)
6. ComputingToday198208 (1982)
7. ComputingToday198208 (1982)
8. ComputingToday198202 (1982)
9. ComputingToday198202 (1982)
10. ComputingToday198210 (1982)
11. Archive item #iv06
12. ComputingToday198209 (1982)
13. Archive item #198206
14. ComputingToday198207 (1982)
15. ComputingToday198206 (1982)
16. YourComputer 1982 12 (1982)