TI-99/4A

TI-99/4

Manufacturer	Texas Instruments
Release date	October 1979 (1979-10)
Introductory price	US$1,150 (equivalent to $4,830 in 2023)
Discontinued	1981
Units shipped	~20,000
CPU	TMS9900 @ 3 MHz
Graphics	TMS9918
Successor	TI-99/4A

TI-99/4A

Manufacturer	Texas Instruments
Type	Home computer
Release date	June 1981 (1981-06)
Introductory price	US$525 (equivalent to $1,760 in 2023)
Discontinued	March 1984
Units shipped	2.8 million[1]
Media	ROM cartridge cassette floppy disk
Operating system	TI BASIC
CPU	TMS9900 @ 3 MHz
Memory	16 KB RAM 256 bytes scratchpad RAM
Graphics	TMS9918A
Sound	TMS9919, later SN94624
Predecessor	TI-99/4

The TI-99/4 and TI-99/4A are home computers released by Texas Instruments in 1979 and 1981, respectively.^[2] Based on Texas Instruments's own TMS9900 microprocessor originally used in minicomputers, the TI-99/4 was the first 16-bit home computer.^[3] The associated TMS9918 video display controller provides color graphics and sprite support which were only comparable with those of the Atari 400 and 800 released a month after the TI-99/4. The TI-99 series also initially competed with the Apple II and TRS-80.^[4]

The calculator-style keyboard of the TI-99/4 was cited as a weak point, and TI's reliance on ROM cartridges and their practice of limiting developer information to select third parties resulted in a lack of software for the system. The TI-99/4A was released in June 1981 to address some of these issues with a simplified internal design, full-travel keyboard, improved graphics, and a unique expansion system. At half the price of the original model, sales picked up significantly and TI supported the 4A with peripherals, including a speech synthesizer and a "Peripheral Expansion System" box to contain hardware add-ons. TI released developer information and tools, but the insistence on remaining sole publisher continued to starve the platform of software.^[4] Architectural quirks of both models reduced the performance benefits of the 16-bit CPU.

The 1981 US launch of the TI-99/4A followed Commodore's VIC-20 by several months. Commodore CEO Jack Tramiel began a price war by repeatedly lowering the price of the VIC-20 and forcing TI to do the same. In late 1982, TI was shipping 5,000 computers a day from their factory in Lubbock, Texas.^[4] By 1983, the 99/4A was selling at a loss for under US$100. Even with the increased user base created by the heavy discounts, Texas Instruments lost US$330 million in the third quarter of 1983^[5] and announced the discontinuation of the TI-99/4A in October 1983. Production ended in March 1984.^[4]

The TI-99/4 was intended to fit in the middle of a planned range of TI-99 computers, none of which were released, but prototypes and documentation have been found after the TI-99/4A was discontinued.