The Atari Mega ST Fleet: Three Machines, Three Jobs
Somewhere along the way, "one Atari ST" turned into three Mega ST 4 machines plus a Mega ST 2. Rather than let them gather dust, each one got a clearly defined purpose, from untouched nostalgia piece to fully upgraded workstation.
What Is an Atari Mega ST?
The Atari Mega ST is a variant of Atari's 16/32-bit ST computer line, released in 1987 and aimed at business and desktop-publishing users. Compared to the standard 520 ST or 1040 ST, it comes in a low, flat desktop case with the floppy drive and motherboard separated from the keyboard, similar to a classic PC tower-and-keyboard setup. It shipped with a built-in Blitter chip for fast graphics operations, which the earliest 520/1040 ST models lacked, making it noticeably better suited for GEM-based desktop publishing software of the era.
Mega STs were sold as Mega 1 (1 MB RAM), Mega 2 (2 MB RAM) and Mega 4 (4 MB RAM), all expandable, and were commonly bundled with monochrome high-resolution monitors for DTP work with software like Calamus or PageStream. The separated case design makes internal expansion and modification considerably easier than on an all-in-one 1040 ST, which is one reason the Mega ST remains a popular base for retro computing projects like the ones documented on this site.
The Lineup
- The heirloom machine, kept as close to factory-original as possible, running the stock TOS 1.04 with a classic floppy drive and its own original Atari keyboard and mouse. Its job is to be a baseline reference: if something breaks on a modded machine, this one proves the fault isn't in the software.
- The "Low" machine, a bargain-bin Mega ST 4 rebuilt with a Cloudy/Storm ST combo for TOS switching and extra FastRAM, a Gotek floppy emulator, an UltraSatan hard disk emulator, a SidecarTridge multi-device for ROM, floppy, and Wi-Fi tricks, and a Wi-Fi modem for dialing into BBSs. It uses an original Atari keyboard and a mouSTer adapter with a USB mouse. This is the demo- and game-machine, optimized for fast disk-image swapping rather than serious productivity.
- The "High" machine, the workstation build. A MonSTerBoard adds 8MB of AltRAM, IDE storage, and flashable TOS (currently TOS 2.06), running Geneva for real multitasking. An ET4000 graphics card drives a dedicated monitor for higher resolutions. A NetUSBee adapter, an Eiffel interface for a PS/2 keyboard and mouse, and a new STPSU for clean, stable power round it out.
- The spare Mega ST 2, a reserve and test machine, kept in largely original condition, used to safely test upgrades before they go into the "real" machines.
Machine Inventory
All four machines were manufactured at Atari Taiwan Manufacturing Co. (indicated by the "A1" prefix in the serial numbers).
| Machine | Serial | Manufactured | Board |
|---|---|---|---|
| Mega ST 2 | A1 7B 4010182 | 11/1987 | CA200019 / C100167-001 Rev.5.0 |
| Mega ST 4 "High" | A1 05 4009044 | 05/1990 | — |
| Mega ST 4 "Low" | A1 08 4011143 | 08/1990 | — |
| Mega ST 4 Heirloom | A1 08 4011015 | 08/1990 | CA200019 / C100167-001 Rev.B |
| Keyboard (Heirloom) | A1 07 4085985 | 07/1990 | CA200043-004 |
Extensions Not Yet Installed
A few upgrades have been bought or built but aren't in a machine yet, either waiting to go in or kept as spares:
- A second Gotek floppy emulator, bought alongside the one fitted to the "Low" machine, still unbuilt and ready for another machine or as a spare.
- An Eiffel Pico USB adapter, bought and configured but not yet installed, so I haven't decided which machine it will go into.
- A new SidecarTridge Multi-device Revision 3, bought as an upgrade over the Revision 0 in use on the "Low" machine, still uninstalled until I decide where to put it.
- An ACSI2STM adapter, bought but not yet in use anywhere, an alternative ACSI hard-disk emulator to the UltraSatan.
- An ST2VGA Enhanced adapter, an active RGB-to-VGA adapter bought as a spare, not currently in use.
- An original Atari STM-1 mouse converted with the laser board, upgraded but not currently in use.
Fun fact: two of the "problem" machines turned out to have nothing wrong with the boards at all, a badly soldered CPU socket and a leftover blitter patch bridge were the actual culprits. Moral of the story: check your solder joints twice before blaming the silicon.
For the full story of how it all started, see the computer timeline.