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Atari ST

The Atari ST was a home/personal computer system released by Atari in 1985. The "ST" allegedly stood for "Sixteen/Thirty-two" which referred to the Motorola 68000's 32-bit internals with 16-bit external busses. Other theories say that ST really stood for "Sam Tramiel", the son of Atari owner Jack Tramiel.

The Atari ST was a competitor to the Commodore Amiga systems. This platform rivalry was often reflected by the owners and was most prominent in the Demo Scene.

Where the Amiga had custom hardware which gave it the edge in the games market, the ST was generally cheaper, and thanks to its built-in MIDI ports enjoyed success as a sequencer and controller of musical instruments. In some markets, particularly Germany, the machine gained a strong foothold as a small business machine for CAD and Desktop publishing work.

Since Atari pulled out of the computer market there has been a market for powerful TOS based machines (clones). Like most retro computers the Atari enjoys support in the emulator scene.

Table of contents
1 History
2 Technical specifications
3 Models
4 Other models
5 External links


Atari had created two released machines in the form of the Atari 2600 console (also known as VCS) and the various Atari 8-bit based home computers. Both of these lines were created around the 6502 CPU and included a number of additional chips assisting this rather basic, but cost-effective CPU in providing graphics and sound. In fact the 8-bit machines had originally intended to be the replacement for the 2600, but they were later "re-purposed" as home computers to cash in on that market segment's much higher selling prices.

As Atari grew and the management was shuffled by Warner (their parent company), the creators of the 2600 and 8-bit machines eventually got fed up and left. A group of them led by Jay Minder formed a small think-tank called Amiga and set about creating the third generation machine, this time based on the much more powerful 68000 CPU.

During this time, the home computer market started to slow down, and the video game market underwent a crash. Warner management decided to "get out" and started looking to sell Atari outright. Meanwhile the same effects were in the process of decimating Commodore International, and eventually their board got fed up and fired Jack Tramiel in January. By May he had secured his funding, bought the remains of Atari from Warner for a very low price, and set about re-creating his empire.

Before Atari was sold, Atari were working towards the launch of a new computer based on the Amiga chipset. Amiga were desperate for a buyer or investor, and the "Warner owned" Atari had paid Amiga for development work (see: "TOP SECRET: Confidential Atari-Amiga Agreement"). When Tramiel took over the company he tried to leverage this and take ownership of the Amiga properties.

Right under the noses of Atari, and at the 11th hour for Amiga, Commodore purchased Amiga lock, stock, and barrel. Tramiel was furious, and the resulting court case lasted for years to come. In the meantime this left Atari in the poor position of having no internal 16-bit design ready for production, while Commodore would soon have the best. In order to address this Tramiel continued development of system that had started at Commodore, Shiraz Shivji was the key engineer on this project and had moved to Atari with Tramiel.

The result was the 520 ST. The machine went from conception to store shelves in a little under a year. As one might expect it was built largely from "off the shelf" parts, and thus had little of the finesse that was the hallmark of their earlier projects (or the Amiga). This was true of the operating system as well, which was a re-labelled version of Digital Research's CP/M-68K, largely compatible with the 8-bit version that had started the microcomputer market almost a decade earlier. Atari had originally intended to release versions with 128 KB and 256 KB of RAM as the 130 ST and 260 ST respectively, but the rapidly falling prices of RAM at the time led them to cancel these versions and it was released with 512K.

Atari machines under the Tramiel rule are marked by infamously "cheap" cases. The original 520 design was quite flimsy, and while the 1040 ST-style case was much stronger, it was also becoming too large and rather unwieldy. In addition the majority of the machines had very poor quality keyboards, so poor that there was a burgoning third-party market for spring kits to improve the feel. They got the design completely right with the Mega series, but this apparently cost too much to produce and the design was not used widely.

An annoying problem concerned the disk drives. Early models were shipped with an external single-sided drive that could store up to 360KB, with an optional double-sided version that stored 720KB for considerably more money. Due to the early sales of so many of the single-sided drives, almost all software would ship on two single-sided disks instead of a single double-sided one, in fear of cutting off all the other owners. This was true even years later, long after the single-sided drives had been off the market.

Additionally they had originally intended to include GEM's GDOS hardware abstraction layer, which allowed programs to draw (display, print, etc.) graphics to any supported device with no changes. This allowed developers to write a program for display to the screen, and get high quality printing "for free". However GDOS was not ready at the time the ST started shipping, and while Atari promised to include it as soon as possible, they never did. This left printing support up to the developers, who had to create their own engines for every possible printer. Similarly the custom "BLiTTER" was to be included to speed the performance of graphics operations on the screen, but this was isolated to their "upscale" machines when it was eventually released years later. As a result, the power of GEM was largely lost on the ST platform, even when GDOS and BLiTTER eventually shipped, it was ignored by developers because it was on so few machines.

On the plus side the ST was less expensive than most machines, including Macintosh Plus, and tended to be faster than most (external link: price comparison). Largely as a result of the price/performance factor, the ST would go on to be a fairly big seller, notably in markets where the foreign exchange rates amplified prices. For this reason the ST was most popular in Europe, especially in Germany. Also, the very crisp picture of its black & white monitor made it quite popular for small-office applications.

Technical specifications

As originally released in the 520 ST:

Very early machines included the OS on a floppy disk, but this was quickly replaced with ROM versions instead. Another early addition (after about 6 months) was an RF Modulator that allowed the machine to be hooked to a colour TV when run in it low resolution mode. These models were known as the 520 STm, although the m did not appear on the label.


A number of machines were released in the ST family. Here they are, in rough chronological order after the original 520 ST:

Other models

There was also some unrelased prototypes: Falcon 040 (external link) (based on a Motorola 68040, new case and slots), and STylus (palmtop)

External links