The Atari 130 ST (ST means sixteen/thirty-two :16 bit data bus & 32 bit address bus) was shown at the Winter Las Vegas Consumer Electronics Show in 1985. It was the great surprise of the show and was presented only six months after Jack Tramiel bought Atari, Inc. (He later named it Atari Corp).
The ST series was rushed onto the market as Atari had originally contracted Amiga Corp. to manufacture a 16-Bit home computer, but legal issues caused the dissolution of that contract resulting in Commodore Computer releasing the Amiga and Atari creating the ST using 'Off The Shelf' electronics to release a computer to coincide with Commodore's release of the Amiga.
It was also designed to be a "Macintosh Killer", and was jokingly called the "Jackintosh". It offered lots of features never found on home computers before: 16 bit microprocessor, lots of interfaces, standard MIDI interface, high graphic resolution, lot of colors, enhanced GUI (Graphic User Interface). It was much more powerful and expandable than the Macintosh (MIDI, graphics, colors, and the like) and competitors weren't very numerous (Commodore 128, PC AT, & compatibles, and the old CP/M machines). That explains why more than 6 million of Atari ST's were sold around the world.
The Atari 130 ST was a prototype for the press demonstration and was never released because of its small memory size : the complete operating system couldn't fit in it. It was replaced by the Atari 260 ST and the Atari 520 ST. Despite its name, the Atari 260 ST was shipped with 512 KB of RAM, because the 192 KB operating system left less than 64 KB of free RAM.
The Operating System was TOS (Tramiel Operating System, later renamed just "The Operating System") which was in fact no more than the old CP/M 68K. Notice that to make easy the transition from the PC to ST, all the high level calls of the TOS (called GEMDOS) were compatible with the DOS calls of the PC (int 21h).
All of the ST family systems used the GEM, which stands for Graphic Environment Manager, GUI (from Digital Research) which has a striking resemblance to the Macintosh GUI (windows, dialog boxes, desktop, desktop accessories, & bitmap fonts) even if it is a bit less friendly than the Apple one.
The 260ST Operating System (TOS & GEM) was supplied on disquette with earlier models, then into 6 x 32 KB ROM chips when the development of the O.S. was fully finished.
ST systems had several dedicated coprocessors for interrupt handling (MFP 68901), sound (the old Yamaha YM 2149, same as General Instruments AY-3-8910 found in MSX computers, Amstrad or Oric), video (a custom chip called "Shifter"), and memory (a custom chip called "GLUE" and the MMU).
The 520 ST featured same hardware basis and 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 originaly came with the OS on floppy as the OS was not completly finished. Very shortly afterward they came with the OS on 6 ROM chips (TOS 1.0).
It was first sold in Germany where it met a great success then released in the United States about six monts 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 conectors (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.
The original Atari 520 ST came with an external 360K single sided 3.5 floppy drive, the SF354. Most dealers either bundled it with separate power supply, or a much neater Cumana or Triangle branded drive at lower cost.
The Atari 520 and 1040 STf were the direct successors of the Atari 260 ST and Atari 520 ST. In fact, they had the same technical characteristics except from built-in floppy drive (hence the f of STf).
The 3.5" floppy disk drive has been integrated with the power supply into the computer. The early first versions of the Atari 520 STf had a RAM based Operating System (they have a 32 KB ROM), this ROM will be quiclky replaced by a 192 KB ROM which holds all the operating system (called TOS 1.0).
An enhanced version of the Atari 520 STf was launched a few months later : the Atari 1040 STf to replace the Atari 520+ : It also had the same characteristics as the 520 STf except its memory (1 MB instead of the 512 KB) and the floppy disk drive : it used 3.5" double side disks (720 KB).
Not long after the launch of the 1040 STf, the 520 STf would be "unofficially" equipped with 720 KB floppy disk drives.
There was also a STfM model with a built-in floppy (the f) and an RF Modulator (the M).
The Atari STe is the successor of the Atari STf (The 'e' stands for 'enhanced') and is almost fully compatible with the STf.
In september 1986, Atari decided to make a successor to the STf. They planned to equip it with enhanced video features : Atari said then that the STe will have a 640 x 400 with 16 colors among 4096 and a 320 x 200 with 256 colors among 4096 graphic modes. Unfortunately, eventually, the STe will have none of these graphic modes.
The new features are :
- a new version of the OS ("Rainbow" TOS 1.6 and later, 1.62),
- a Blitter chip to quick perform memory moves (it is the the Mega STf one),
- the video chip (Shifter) has been enhanced: the STe can perform, as the Amiga, hardware scrolling in all directions and it is possible to write into the video counters. It also handle 4096 colors instead of 512, unfortunately, it can only display a maximum of 16 of them (without trick).
- 'phase lock' of the video output to an external video source permitting direct linking to genlocking device.
- It has enhanced sound features too: two 8 bit PCM (Pulse Coded Modulation) channels which can replay stereo sound at 6.25, 12.5, 25, or 50 KHz and which can be mixed with the 3 FM channels.
Despite its new and interesting features, the Atari STe was a flop in the marketplace. The STf market was too important and the software editors (especially game editors) didn't sell STe versions of their products.
Not long after this, Atari launched the Mega STe to replace the Mega STf.
There was an interesting variation on the STe in the R&D labs of Atari, called the STe+, which had an AMD 286 chip and a small IDE hard drive built in. Quite why this was abandoned nobody really knows, but a number of working prototypes were found in Atari's Mexico office when Atari finally blinked out of existence and have appeared on ebay from time to time.