The Atari TT was a kind of a super Atari STe. As the other Atari computers, it was very long awaited. It was presented as a competitor of the Macintosh and was one of the first to offer a huge graphic resolution (1280 x 960).
The first TTs had a 16Mhz CPU. A small daugther card was supplied later to use a 32 MHz CPU, then all the TTs were shipped with a 32 MHz CPU.
It had a lot of extension connectors (like VME, VGA or SCSI) to allow it to be connected to a lot of standard peripherals.
It had also several features of the Atari STe, like the sound system, but contrary to this one, it didn't have its enhanced video features (fine scrolling) and its Blitter (custom chip designed to move bitmap blocks).
It had, like the Amiga computers, a special memory organisation : 4 MB, expandable to 12 MB (called ST RAM) was used for coprocessors (video, sound, ASCI) and the rest (called TT RAM which can be located on the motherboard or on a VME card) was used only for 68030 processor and wasn't slowed by peripherals accesses. Both SCSI and serial could do DMA transfers directly to TT-RAM.
A special version of the TT was designed to be a UNIX station, called TT/X it was supplied with UNIX System V R4 and WISH (an extension of OSF Motif).
However the TT and the TT/X had no success and there was no (or so few) software especially designed for this computer. Notice that a Macintosh emulator (called Spectre GCR - done by Dave Small-) turned the Atari TT into a very fast Macintosh clone : Macintosh software could be used on the TT, and often they ran faster than on the original Mac!)
Actually there never was a 16Mhz version. They considered using the 68020 at 16Mhz but late in development the switched over to the 68030 running at 32Mhz. They kept tha bus at 16Mhz for technical reasons and for compatibility with ST apps though.
Saturday 30th June 2018
The Atari TT was a success in some circles. Certainly it wasn''t a flop. But it wasn''t the big success that the Atari ST was. It was simply too pricey. Even if "Power without the price" was still true for this machine, it was more capable than the PCs or Amiga''s of its time. The latter all had bigger price tags. The reason why it wasn''t the success the ST was, was because the thing was aimed solely at business, while Atari had a loyal home computing following. Anyway, it was a splendid machine. Every bit as reliable as the ST, but super fast and with even greater connectivity.
A few bits of information: The TT/X with UNIX featured the standard TT hardware, the only difference that I am aware of was having the UNIX system pre-installed. It appears to have been very rare, even by TT standards, though it was not vaporware, and a few have turned up.
The Appletalk LAN port never had any software released to support it, though TOS 3.x (TT TOS) does "see" it. Appletalk LAN was also provided on the Falcon, so Atari seemed pretty confident that they would do something with it eventually.
Apparently the 256 colour TT-Low resolution (an odd addition to a system aimed mainly at high-res DTP and CAD/CAM applications) was apparently a hang over from the STe. The STe was originally intended to have this resolution but it was $ped from that design for some reason, but picked up again in the TT. Also, the "Spectrum" mode is not an "official" mode, but can be done using programming "tricks", and can actually use the full 4096 colours of the palette. The same tricks can be done on the STe and stock STs (with 512 instead of 4096 cols, due to their smaller palette). The name comes from the Spectrum 512 image editor, which famously used this trick in a very elegant way.
Finally, just to correct the RAM specification. The system can support up to 256mb TT-RAM (on a dedicated RAM card). ST-RAM was less, though I''m not sure of the upper limit.
Thursday 29th December 2011
Motorola MC 68030
68882 (numeric processor)
2 MB (up to 26 MB)
40 x 24 / 80 x 24 / 80 x 30 / 160 x 60 (bitmapped graphics)
320 x 200 (16 col) / 320 x 480 (256 col) / 640 x 200 (2 col) / 640 x 400 (2 col) / 640 x 480 (16 col) / 1280 x 960 (mono).
16 among 4096 (512 with a special CPU consuming 'Spectrum' mode)