Atari TT030 - History

History

Atari Corporation realized that to remain competitive, they needed to begin taking steps to exploit the power offered by other processors in the Motorola 68000 series. At that time, the best option was the 68020. It was the first true "thirty-two bit bus/thirty-two bit instruction" chip from Motorola. Unlike the original 68000 used in the STs, the 68020 was capable of fetching a 32-bit value in one cycle, while the older STs took two cycles to fetch a 32-bit value.

The TT was initially designed around the 68020 CPU, however as the project progressed, Atari Corp. realized that the 68020 was not the best option for the TT. The 68020 still lacked certain important features offered by the next successor in the 68000 line, the new 68030. The new 68030 featured a full 32-bit address/data bus and internal registers; separate Supervisor, User, Program, and Data virtual memory spaces; built-in memory-management hardware; and 256-byte on-chip instruction and data caches.

When the decision was made to switch from a 68020 to a 68030 CPU, it presented a whole new set of problems. The original specifications for the TT's clock speed was 16 MHz, which was selected to maintain backward compatibility. The existing ST chips used in the TT (DMA and video chips for example) could not handle anything over 16 MHz. Some software also had problems running at faster speeds. To make the system work with a 32 MHz 68030, Atari Corp. had to scale back their plans somewhat, and add a large amount of cache to the system. As a result, the processor runs at 32 MHz, while the system bus runs at 16 MHz. This is similar to the tactic employed by Apple with the ill-fated Macintosh IIvx and later employed by makers of PCs with an Intel 80486DX2 CPU.

TOS 3.01 was the operating system that came with the Atari TT. It was a 512 kB ROM specifically designed for the TT. However, it did not feature pre-emptive multitasking. Another variant, known as TT/X, used Unix System V R4 and WISH (motif extension).

The TT030 was first introduced at CeBIT in Hannover, Germany and launched in 1990. It retailed for $2995 with 2 MB RAM and a 50 MB hard drive. The US release came the following year. In 1993, Atari Corp.'s exit from the computer business marked the end of the TT. A number of TT machines were built as developer systems for Jaguar.