NamingGenerally can be said: First comes a usually rounded number that indicates the memory amount. Thus, an Atari with 256 KB of memory is called the 260, with 512 KB of memory is called a 520 and then one with 1024 MB memory is called 1040. A 2080 was available short time only and even a 4160 existed but only as a prototype. After the number there follows "ST". ST means Sixteen / Thirtytwo, which means 16/32 Bit (as it is a mixture of 16 and 32 bit system). The Atari TT is only 32 bits, so Thirtytwo/Thirtytwo. Thereafter, there can be the following letters:
M = modulator, a TV modulator is integrated with an RF antenna connection
F = floppy disk, a floppy drive is inside the case.
E = Extended, suggesting improved hardware
1040 STFM has 1024 KB memory, is a 16/32 bit system and has both a TV modulator and an integrated floppy drive. Actually not that hard but there are models which do not follow the discription above...
Was plnned with 256 KB. But 256 KB was not enough and because the commercials had already been printed, this model was available short, but had also 512 KB of RAM. Like the Amiga 1000 the Atari ST operating system TOS had to be loaded from disk. It has been permanently installed in later models. The computer was similar to 8-bit computers and had the drive and external power supply.
Same as Atari 260 ST but was sold in a longer time period. TOS was loaded from disk.
The 520STM has integrated both a TV modulator and an integrated floppy drive. TOS was built-in. Later renamed to 520ST
Also the name suggests the computer has 512 KB memory, the plus model has 1 MB RAM (it correctly would have to be called 1040). Everything else was technically identical to 520 ST.
The 520STF has a built-in 3½-inch-Disk drive. The case was bigger and also the PSU was built-in.
The 520STFM is the same as 520STF but has a built-in modulator.
Has 1 MB RAM and a disk drive built-in. The case is the same as the Atari 520 STF/STFM uses.
The 520STFM is the same as 1040STF but has a built-in modulator.
This model was only sold short and therefor is very rare. It has 2 MB RAM and also there is no "F" it has a built-in 3½-inch-Disk drive.
Mega ST (1987-1991)
A 1040 ST in a Desktop-case and separate keyboard. Available with 1, 2 or 4 MB RAM. It also features a Blitter chip.
Enhenched 1040 ST with more colors and better sound. Also a Blitter was built-in. New TOS und easy RAM expansion up to 4 MB possible. Disk drive and PSU built-in.
Like 1040STE, but with 512 KB RAM only.
Successor to the ST-Series. Atari TT030 has a Motorola 68030 CPU and is a 32 Bit Computer. It was a professional computer and it worked with 32 MHz (CPU, all other parts 16 MHz).
Mega STE (1991-1994)
Atari MegaSTE ist an enhenched Desktop-variant of Atari 1040 STE. It was successor to the Mega ST and the market position was between the cheap 1040 STE and the High-End-Model TT030.
Falcon 030 (1992-1994)
The Falcon had a Motorola 68030 CPU clocked at 16 MHz. He was supposed to replace the 1040 STE, however, but had outdated hardware and could not be enforced against more powerful and cheaper x86 computers. It was Atari's last home computer. He looked like an Atari 1040 STE, the color of the keyboard changed from white to dark grey. Tasten wechselte von weiß auf dunkelgrau.
TOS-ChipsThere are TOS on six, four and two chips. In the case of two chips the socket LU4 and U7 is used. Below is a list.