Texas Instruments TI-99/4

( at launch in North America)

  • Max. 256 × 196 pixels
  • Max. 15 colors
  • Max. 32 × 24 characters per line
  • Three graphics modes
  • Max. 32 Sprites
  • 3 tone generators
  • 1 noise generator
  • Plug-in modules
  • Audio cassettes
  • 5.25 "floppy

Graphics Programming Language

The TI- 99/4 was a home computer from Texas Instruments, which was presented to the public in June 1979 for the first time, but ( because of problems in terms of production and radio approval ) until the beginning of 1980 was available in North American trade. The following year he was replaced by a modified version that henceforth bore the name TI-99/4A. The late launch of the PAL version of the TI- 99/4 in Europe, the successor model TI-99/4A has a much higher awareness and penetration rate obtained as the TI- 99/ 4

In total, approximately 20,000 units of the first home computer from Texas Instruments were sold.

Differences to the successor model TI-99/4A

Between the TI -99 /4 and TI-99/4A his successor there was the following main differences:

  • The TI-99/4A had the bigger and much better keyboard, which was virtually the TI- 99/4 only of buttons, how to find a calculator. Due to the smaller number of keys and the lack of distinction between uppercase and lowercase letters conditionally, some control functions were (not in combination with the Ctrl or Control key but ) operated in combination with the Shift key ( Shift) for the TI - 99/4. This required of persons who were accustomed to use the shift key to write capital letters, a high level of discipline, because a wrong button combination could serious consequences have (examples: ⇧ -C caused a program abort, ⇧ -Q to restart the computer ).
  • The copyright notice on the opening screen of the TI- 99/4 was equipped with the year 1979, during the TI-99/4A the year was given in 1981.
  • In addition to TI BASIC program to calculate algebraic expressions called "Equation Calculator " was integrated into the TI- 99/4. This can be explained why the TI -99 /4 to 5 Kbytes larger ROM required.
  • While the TI -99 /4 of the graphics processor TMS9918 was built, the TMS9918A was used in the TI-99/4A, which had an additional display mode.
  • The TI- 99/4 could only accept uppercase and display the TI-99/4A and lowercase letters.
  • In contrast to the TI-99/4A TI -99 /4 with headphone jack and / or speakers equipped. Where earlier versions of the TI-99/4A had the elongated Aluminiumschildchen imprinted with " Solid State Software", was the TI -99 /4 of the slider for the volume setting. The board with the necessary amplifier was under the manhole cover.
  • The TI- 99/4 power supply was in shape considerably larger than that of the TI-99/4A because it contained, in addition to the transformer in addition, the circuit board with a rectifier and voltage regulators. When TI-99/4A this board was under the cover of the module slot and replaced thus there the board of the amplifier from the TI- 99/ 4
  • Since the power supply of the TI-99/4A so delivered unregulated AC, the TI- 99/4, however, regulated DC, has been modified as well as protection of the connector. Although he still fit mechanically but electrically presented only when TI-99/4A a contact.
  • The module bay was the TI- 99/4 differently than the TI-99/4A.

Otherwise, the TI -99 /4 and TI-99/4A were built largely identical, so can be more details on the TI- 99/4, see the article for the TI-99/4A.

Sprite (computer graphics) ROM cartridge Floppy disk TI BASIC (TI 99/4A) Texas Instruments TI-99/4A Abort (computing) Read-only memory
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