TI-99/4A Documentary
Added 2025-08-25 22:42:35 +0000 UTCAfter 2 months or so, here it is. Subtitles and thumbnail will be finished tomorrow.
Comments
I had one of these as well (with the expansion box, 32K and disk drive, but the chunky RS232 box). I got to learn all the gnarly guts of the system by being young and energetic and making an emulator for it back in the 90's. Given that, I spotted some minor factual errors in the video, but none of which actually change the basic points :). * The 32x24 graphics mode didn't allow every character to be individually colored, just every 8 character codes in a group. * And while the 9918A bitmap mode allowed each pixel to be changed, it also allowed two colors per each 8x1 pixel chunk. Not perfect APA, but good enough. * The GROM memory was 0x1800 bytes per chip (not 1800 decimal), so the maximum GROM cartridge size in 6 banks was actually ~36k. * While TI Extended Basic did move a lot of the logic to cartridge ROM (16k + bank-switched, in fact), it also used 24k of GROM banks for data and some of the less often used routines. So a fair bit of the logic was still going through the slow GPL interpreter. * The internal structure of the ROMs was interestingly designed for massive expandability -- ROM/GROM/peripherals all had a standardized header allowing for new devices, BASIC subroutines, and startup code to be added by a cartridge or expansion card/box. Given that, it is indeed a shame that TI was so hostile to developers until it was too late. (Fortunately for me, when I inherited the system, it came with Extended BASIC and the Editor/Assembler and was fully exploitable, once I figured out how.) I'd recommend visiting https://www.unige.ch/medecine/nouspikel/ti99/titechpages.htm for a ton more in-depth knowledge about the original hardware and later user mods.
Edward Swartz
2025-08-28 17:48:16 +0000 UTCAt one point I was thinking: Why? I wonder what the machine would’be been like if at the time of the CPU change they’d just redesigned the whole thing and given the world the first 16-bit home computer.
Johan Petur Klüver Dam
2025-08-28 16:32:12 +0000 UTCThanks for the video! Interesting strange machine yeah! About the TMS9918A: in this part of the world (Europe) we probably best know it as the graphics chip of the MSX1 computers, I had one as a kid and are very familiar with its capabilities and limitations;-)
MrHammond
2025-08-26 18:20:37 +0000 UTCGreat video! The TI99/4A was my first computer from K-Mart December of 1981. It was a really neat machine and had the speech synthesizer. You playing Parsec brought back memories. Kept it till 84 but support faded fast along with products. I then Bought a second hand C64 with a 1541 disk drive because a kid's dad down the street bought the C128. Not to long ago My wife knowing I wanted to get back to the Commodore bought me a 1983 SX-64 which I love and then I bought a C64C. Awesome channel Thank You!
Keith Exum
2025-08-26 16:55:25 +0000 UTC
