#### Back to index | # Info for ti990_10

#### Texas Instruments Model 990/10 Minicomputer System

Known Issues:
The controller panel is not emulated yet.
The computer seems to lock when running various installation scripts, and
rebuilding the system.

Usage:
This driver emulates a TI990/10 CPU with mapping option, 1Mbyte of RAM,
a generic disk controller at TILINE base >1ff800, a generic tape controller
at TILINE base >1ff880, and a 911 VDT at CRU base >0100.
This is enough to build DX10 or DNOS. I have been able to build a working DX10
3.7 or 3.6 system from the relevant build and backup tapes. (Tape loaded as
tape unit #1 and a blank disk image as disk unit #1 (with the SCOSTA flag
at offset >A4 set to >0002, so that the build tape does not try to format the
disk)). I have even managed to install the fun and games tape, and play pacman.

History and Trivia:
Texas Instruments has been building minicomputers since the late 1960s through
the 1980s.
Around the summer of 1973, they started to design the TI990 as a successor to
the 960 and 980 computers they were building at the time. In 1974, TI started
to build the prototype of the TI990 series, the TI990/9.
In 1975, they released the first commercial system, the TI990/10. It was
a minicomputer built with TTL logic. Although it was a 16-bit CPU,
it supported an optional mapper to expand address space from 64kbytes
to 2Mbytes.
The TI990 series development continued. In 1975 or 1976, TI started shipping
the TMS9900 microprocessor, which implemented a subset of the TI990/10 feature
set. Two CPU boards were built around the TMS9900: the TI990/4 (1976) and
the improved TI990/5 (date unknown). These boards were much cheaper than the
TI990/10, but they could only address 64kbytes, did not implement the memory
bus fully (no DMA support), and could not run the DX10 OS.
Around 1978, TI released the TI990/12, a higher-end TTL implementation, which
was faster, and supported many additional instructions and features when
compared to TI990/10. It was replaced with a revised but similar TI990/12LR
computer in 1982 or 1983.
In 1981, TI released the new TMS99000 microprocessor. In 1982, they replaced
the TI990/10 CPU with a cheaper, smaller, faster, and more energy-efficient
TI990/10A board built around the TMS99000 CPU. Additionally, they released
an all-in-one Business System 300 (1982), later replaced with the Business
System 300A (1984). Both computers included the CPU, RAM, video terminal, and
hard disk/tape interface in a terminal case.
The TI990 series must have been abandoned around 1985, when TI introduced
the S1500 series built around a 68020.
The TI990 computers were primarily used for business applications.
Two disk-based OS were available. DX10 was a multi-tasking, multi-user OS.

DNOS (released around 1981) was similar to DX10 and mostly compatible with it:
it supported extra features but it was bigger and slower. Neither OS could run
on the lower-end 990/4 and /5 systems, but a kernel and various OS utilities
were available as static-link libraries for embedded applications.

created on Mon May 19 14:44:27 2003