Texas Instruments’ Personal Computers

Texas Instruments (TI) had been a pioneer in transistor, integrated circuit, and semiconductor design, and it was a major player in the calculator market. However, it took its time entering the home and business computer markets and fared poorly in both areas.

Texas Instruments TI-99/4 header

The Home Computer

Texas Instruments TI-99/4 computerTI’s first home computer as the TI-99/4, which shipped with a 13″ color monitor and sold for $1,150 when it debuted in October 1979. The computer had a calculator-style 41-key chiclet keyboard, no lowercase text (not unusual in the 1970s), and was the first personal computer with a 16-bit CPU and ran at a seemingly respectable 3 MHz while most home computers ran at 1-2 MHz. It was also the first home computer to use program cartridges.

The TI-99/4 was announced at the June 1979 Consumer Electronics Show and first came to market in October 1979. Because Texas Instruments couldn’t get the FCC to approve its RF modulator, the company decided to bundle the 99/4 with a monitor, a modified 13″ Zenith TV refitted for use as a computer display. (In January 1980, the FCC got a waiver for its RF modulator, allowing sale of the computer without the monitor and reducing its retail price to $599.)

The TMS 9900 was indeed a 16-bit CPU, but TI made some poor design choices in both the chip design and the architecture of the 99/4. To keep production costs down, the 9900 CPU could only access 256 bytes (not kilobytes) of fast 16-bit memory. The rest of the machine’s memory was 8-bit RAM that was accessed via the TMS 9918 graphics chip.

The 99/4’s claim to fame was speech synthesis, an area where TI lead the field.

Because TI was a calculator company, they built an Equation Calculator into the ROMs of the 99/4. It worked like a simple scientific calculator.

The 99/4 was replaced by an improved model, the 99/4A, in August 1981.

Nobody seems to have exact sales figures for the 99/4, with estimates ranging from a low of 20,000 units to a high of 100,000.


TI-99/4A computer systemThe TI-99/4A improved on the original 99/4 in a number of ways. It has a full-stroke keyboard with 48 keys and supports lowercase text. The Equation Calculator was not part of the ROMs on the 99/4A. An improved graphics chip, the 9918A, gives the newer model bit mapped graphics, which the original does not support. The newer model originally retailed at $525 and became quite successful, and some have estimated that at one point it may have accounted for one-third of home computer sales.

When Texas Instruments introduced its own line of calculators, Commodore was one of many companies forced out of the calculator market. TI was selling assembled calculators for less than these companies paid for parts. Commodore founder Jack Tramiel saw his opportunity to get back at TI and started the great home computer price war of 1983. Time and again prices were slashed until TI had to sell the 99/4 below cost to compete – losing oney on every sale. By the end of the year, Commodore and Atari were hurting; TI had thrown in the towel.

TI-99s That Might Have Been

TI had been working on two models to expand the TI-99 line.

Bill Cosby with TI-99/2The TI-99/2 Basic Computer (yes, that was its name) was intended to compete with the Timex Sinclair 1000 at $100. The 99/2 had a 10.7 MHz TI 9995 CPU, over 3x the speed of the 9900 CPU in the 99/4A. 4 KB of RAM was built into the CPU, as well as 256 bytes of scratchpad RAM – the 99/4A only had scratchpad RAM available to its CPU. Cartridges plugged into the back of the computer.

That was the good part. The bad part was that the 99/2 didn’t support color at all, had a membrane keyboard, and didn’t do color. Seriously, a home computer has to do games, and games call for color. Oh well, at least they had Bill Cosby ready to shill the new low-end TI-99 model.

A few 99/2 computers made it out of Texas Instruments, but the model was never officially released.

Texas Instruments 99/8The TI-99/8 was going to be a top-end model, shipping with 64 KB of RAM and able to support 15 MB. Speech was built-in. At full speed, the 9995 CPU ran at 10 MHz – 3x as fast as the 99/4A (some sources say 12 MHz and 4x as fast). It was intended to sell at $600 and take on Apple.

Only 250 99/8s were ever assembled, and just 150 of them were finished to specification. Only a handful of these ever made it out the door.

The End

Commodore pushed TI so hard that it was selling the 99/4A for $99 and never had an opportunity to launch the 99/2. Losing money with every sale, TI just couldn’t go on trying to compete in the home computer market.

On Friday, October 13, 1983, Texas Instruments announced it was leaving the home computer market. Remaining inventory of 99/4A computers was sold off for as little as $50.

The TI Professional Computer

Texas Instruments Professional ComputerEven while the 99/4A was selling well, Texas Instruments decided it needed to build a computer for the business market.

The Texas Instruments Professional Computer was an MS-DOS computer that was not IBM compatible, an issue that doomed many other early DOS computers, some of which were superior to the IBM PC in one or more ways. The TI Professional Computer and Portable Professional Computer were both introduced on January 31, 1983. One unique feature was voice recognition software that allowed users to speak certain commands.

Technical Specifications

  • 5 MHz 8088 CPU
  • 64 KB RAM standard, expandable to 768 KB
  • 320 KB double-sided 5-1/4″ floppy drive
  • 5 expansion slots
  • video card supports both monochrome and color displays at 720 x 300 pixels
  • ergonomically grouped keyboard

It seems everyone had a better idea for keyboard layout than IBM. One nice feature of the TI keyboard is the “+” configuration for the arrow keys. By 1983 it was already becoming common for the F-keys to be clustered in groups of 4 above the keyboard – not to the left like the original IBM PC keyboard.

Texas Instruments Professional Computer keyboard

Like many IBM non-compatibles, these can be expanded to 768 MB of RAM, 128 MB more than the 640 KB limit IBM imposed. Both models support 720 x 300 pixel graphics. The Portable could be upgraded from a 9″ monochrome display to a 9″ color screen.

Even though this used much of the same hardware as the IBM PC, the fact that it couldn’t run IBM PC software doomed it – and many other “better idea” attempts to improve upon the new standard IBM had established.

TI abandoned the PC business in 1985.

Further Reading, TI-99/4 and 99/4A

Further Reading, TI Professional Computer

Keywords: #texasinstruments #ti994

Short link: https://goo.gl/YC7r6O

searchword: ticomputers