The entry into the home market - The Acorn Atom (1980).

The Atom was Acorn's first attempt to break into the home market. Released in 1980, it continued Acorn's association with the 6502 processor, with the 1 MHz 6502A used in the Atom. The operating system and an integer-only version of BBC BASIC were provided in 8 Kb of ROM and 2 Kb of RAM (expandable to 12 Kb) was available.

The Atom was a highly expandable machine, with UHF TV and tape connectors provided as standard, as well as two expansion ports. A wide range of peripherals could be added using these ports, including a floppy drive, using an early version of Acorn's DFS (Disc Filing System), and Econet (a networking system devised by Acorn and the University of Cambridge). A high resolution video graphics card and floating point extension ROM for BASIC could also be added.

The graphics system was capable of 32 by 24 and 16 by 12 character text modes and 128 by 96 and 256 by 192 pixel graphics modes, with four colours available simultaneously from a total palette of 8. The video controller selected was the 6847, which was the most advanced available at the time, but was slightly flawed in that it was basically designed for an NTSC display, and could only produce a signal at 60 Hz, rather than the 50 Hz required by PAL. As a result it was incompatible with about 20% of TVs. A multiple channel sound system was also supplied.

The Atom was sold in a ready made form, for £170, or in self-assembly form for £120.

Next: The BBC Computer Literacy Project - The BBC Micro (1981).

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Robert McMordie

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