The second model in the ST range, the STM was virtually identical to the original ST, but with a built-in TV modulator (but still with an external floppy drive). The machine cost £400 when released.

The 520 ST featured same hardware basis and the same amount of memory as the 260 ST.

The main difference between them was the built-in ROM TOS operating system and GEM Graphics Interface. In fact, the Atari 520ST originally came with the OS on floppy as the OS was not completely finished. Very shortly afterward they came with the OS on 6 ROM chips (TOS 1.0).

It was first sold in Germany where it was met with great success. It was then released in the United States about six months later. Colour and monochrome version were available. Sadly, users of the colour version couldn't expect programs written for the monochrome version to work until someone wrote an emulator allowing the software written for the monochrome version to run on a colour monitor.

Atari was the first company to offer built-in MIDI ports. This made the computer very popular with musicians. One game even used the MIDI connectors (Midi Maze) to connect up to 16 computers together in a MIDI network.

The 520 ST+ offered 1 MB of RAM instead of 512 KB. As the main board was designed to provide space for only 512 KB of RAM (16 x 41256 type chips), the second 512 KB bank chips were soldered on top of the original chips.

Apparently, 1 Mb versions were sold as Atari 1040s in Australia.

The model 520 STM came with a built-in TV modulator allowing a direct connection with the TV-set.

Manufacturer: Atari
Date: 12th September 1986

This exhibit has a reference ID of CH5769. Please quote this reference ID in any communication with the Centre for Computing History.