I ran my own blog from November 2006 till October 2014. All posts are still online, but I don't have time to update it anymore. Please note that all images and media files have been removed when the backup was moved to a new host in early 2016. Enjoy!

A tribute to the Atari ST computer

20. december 2007

Okay, the Atari ST was a really cool home computer, but to you know anything about the facts and the technology behind it? So here's my very short (but hopefully interesting) story of the Atari ST.

Let's start with the background story. After Commodore founder Jack Tramiel left its company in January 1984 he was looking for a new computer company he could acquire. He finally took over Atari, which was in financial trouble back then. Shiraz Shivji, the father of the C64 who came on board along with Tramiel, had also left Commodore for Atari and Tramiel now asked him to develop a new low-cost, high-end computer system. All other Atari computer in development back then were cancelled and Tramiel fired most of Atari's staff.



Shivji started to develop a computer system using the Motorola 68000 CPU, a 32 bit processor featuring a 16 bit data bus (thus the name "ST", which officially stands for "Sixteen/Thirty-two"). The original ST featured 512 KB of RAM and a 3.5" floppy disk, nevertheless Shivji was able to build the system using an absolute minimum of hardware which allowed to keep the costs low.

After the hardware design had been completed they had to look for an operating system - developing an inhouse OS was not an option as the ST was planned to ship soon. Microsoft offered to port an early Windows version to the ST, but this would have taken two years as DOS didn't run on 68K hardware. 

Atari finally opted for Digital Research's CP/M-68K, which was essentially a direct port of CP/M's original, mature operating system, plus Digital Research's GEM graphical user interface. The problem with this decision was that CP/M was becoming increasingly outdated in comparison to MS-DOS 2.0 in 1985, it did not support sub-directories and did not have a hierarchical file system for example. 

Digital Research was already working on an improved OS called GEMDOS, and finally they integrated parts of the GEMDOS OS into CP/M to realize a hierarchical file system for example. So finally the Atari OS, officially called TOS (The Operating System), was a CP/M port with GEM and custom library ports.

The first ST was the Atari 520ST which shipped in 1995. Early machines booted TOS from a floppy, later ones had the TOS in an onboard ROM. The ST was less expensive than the Apple Macintosh plus, it was fast and became quite popular because of its good price/performance factor. An Atari ST including terminal emulation software was also much cheaper than a Digital VT220 terminal for example.

The main competitors of the Atari ST were the Apple Macintosh and the Commodore Amiga. The Macintosh was limited to a monochromatic display on a smaller built-in monitor, in fact the Atari ST was the first computer to come with a fully bit-mapped color GUI and it was considered to be a cheap but powerful CAD and office computer. It was also the first home computer with integrated MIDI support, which made it quite popular among musicians.

The 1040ST was the first personal computer shipped with a base RAM configuration of 1 MB, and at $999 in the U.S. it became the first computer to break the $1000/megabyte price barrier. It also had a built-in floppy drive. A version featuring a pizza box form factor, a detached high-quality keyboard and internal expansion slots was shipped as the "Mega" to fulfill the needs of the professional market.

In late 1989, Atari released the STE, the first major revamp of the platform since the original release of the ST four years earlier. It featured an updated TOS and improved hardware - an increased colour palette of 4096 colours, Genlock support, a blitter chip which could quickly move large blocks of data, better sound and more joystick ports. Nevertheless it still used the same Motorola 68000 processor running at 8 Mhz.

There were some serious problems with the STE models. First of all, there were software and hardware conflicts that made them incompatible with a certain number of programs and expansions for the classic ST models. Furthermore there were only very few programs making use of the enhanced STE features, most software still only supported the well known ST hardware features.

The high-end workstation-oriented TT ("Thirty-two/Thirty-two" using a 32 MHz Motorola 68030 CPU) was released in 1990, also featuring improved graphics, more powerful support chips and an integrated harddisk. There was also an STE shipping in a TT case, this one was called the Mega STE which ran at 16 Mhz and had many more improved featured compared to the original STE, but was still less expensive than the TT.

The last ST computer was the Falcon, a multimedia computer also based on the Motorola 68030, operating at 16 MHz, but with improved graphics and greatly enhanced custom chips, including high-quality audio DSPs. Released in 1992, it was cancelled by Atari the following year. 

In 1993 Atari cancelled development of all ST hardware. Some third party vendors continued to ship Falcon and TT-compatible machines using 68040 and even 68060 processors (the Motorola chip that was originally planned to challenge the Intel Pentium, but was never used by Apple because of their switch to the PowerPC architecture).

Even today, and despite the lack of a hardware supplier, there is still a small active community dedicated to keeping the ST platform alive.