Atom vs. Electron

The Acorn Atom was a home computer made by Acorn Computers Ltd from 1980 to 1982 when it was replaced by the BBC Micro (originally Proton) and later the Acorn Electron.

The Atom was a progression of the MOS Technology 6502 based machines that the company had been making from 1979. The Atom was a cut-down Acorn System 3 without a disk drive but with an integral keyboard and cassette tape interface, sold in either kit or complete form. In 1980 it was priced between £120 in kit form, £170 ready assembled, to over £200 for the fully expanded version with 12 KB of RAM and the floating point extension ROM.

The minimum Atom had 2 KB of RAM and 8 KB of ROM, with a fully loaded machine having 12 KB of each. An additional floating point ROM was also available. The 12 KB of RAM was divided between 5 KB available for programs, 1 KB for the page zero and 6 KB for the high resolution graphics. The bottom kilobyte of memory was used by the CPU for stack storage, by the OS, and by the Atom BASIC for variable storage of the 27 variables. If high resolution graphics were not required then 5½ KB of the upper memory could be used for program storage.

Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the UK. These included the Acorn Electron, the BBC Micro, and the Acorn Archimedes. Acorn's BBC Micro computer dominated the UK educational computer market during the 1980s and early 1990s.

Though the company was broken up into several independent operations in 1998, its legacy includes the development of RISC personal computers. Its RISC OS operating system continues to be developed (as two forks) by RISCOS Ltd and RISC OS Open. Some of Acorn's former subsidiaries live on today—notably ARM Holdings, which is globally dominant in the mobile phone and PDA microprocessor market.

Due to its innovative concepts and the future success of many of its former employees,^{[citation needed]} Acorn is sometimes referred to as the "British Apple". In 2010 the company was listed by David Meyer in ZDNet as number nine in a feature of top ten fallen "Dead IT giants". Many of Britain's IT professionals gained their early experiences on Acorns, which were often more technically advanced than commercially successful US hardware.