Cartridge, Disk, HD and Cassette software
Move down the page to see the TI99/4 & TI99/4a, Geneve, PSystem, TI99/8, TI99/2, Tomy Tutor, MBX and Cortex software available here.
Cartridge: Cartridges are in MAME .rpk format.
Disk: Disk are in .dsk format.
Cassette: Tapes are in .wav format.
.HD: Hard drives are in .chd format
FinalGrom: FinalGrom files are in .bin format.
TI99/4a software
This is software for the TI99/4 and TI99/4a computers. It is divided into separate categories according to type. Some of the software will also work on the other family of 9900 based computers on this list.
Applications
Here is software like TIartist, TIBase, TIwriter and MS Multiplan and many, many more.
Books
Software from books on programming languages, Compute! books and many more.
Development
Software for programming languages such as various Extended BASICs, Assembler, C, Logo and more.
Education
Educational software from TI, Milken, Schoolastic, Plato and many more.
Games
Games are divided into four sections:
Mygames – Disks
Currently there are about 350+ games available.
Magazines&Newsletters
Software from magazines and newsletters like IUG, Tigerclub, Compute! and more.
Music
Lots of music software created with the TI99.
Utilities
Utility programs like 4aDOS, Disk Manger 2000, Terminal Emulator II and more.
Cassette Tapes
Tapes like Mini Memory Line by Line Editor, Logo, Tunnels of Doom and more.
FinalGrom
Other 9900
Here is software for the Geneve, TI99/8, TI99/2, MBX, PSystem, Tomy Tutor and Cortex systems.
Geneve
Software for the Myarc Geneve 9640 computer. The Geneve was a complete computer on a card that was to be set in the TI PEB. With faster processor, more memory, 80 column text and higher graphics it was quite the upgrade from the TI99/4a.
TI99/8
Software for the never released TI99/8 computer. The 99/8 was to be an upgrade for the TI99/4a with more memory, speed and built in XB. Note: many of the documents for the 99/8 and 99/2 are still in beta form but usable.
TI99/2
Software for the also never released TI99/2. The 99/2 was a b/w, 4k low cost computer with no sound to compete with the TS1000.
PSystem
Software for the P-Card PSystem. The P-card was a card for the PEB that turned the TI99/4a into a PSystem computer. This was a whole different computer system that made the TI99 compatible with other PSystem computer but not compatible with the standard TI99 software.
MBX
Software for the Milton Bradley MBX game system. A very advanced game system add-on for the TI99/4a. The MBX had it’s own keyboard, voice activated commands and own set of Milton Bradley game cartridges that used the advanced features.
Cortex
The Powertran Cortex was a 16 Bit Computer that appeared as a construction project in Electronics Today International (ETI) magazine in 1982, 83. It started out life as a design of TI-UK engineers who found themselves in conflict with TI. So the solution was to have it published in ETI and have kits from Powertran.
Cortex BASIC that runs on the TI99 (Cartridge and Disk)
CDOS DOS for Cortex
MDEX DOS and files for Cortex
Source: http://www.powertrancortex.com/index.html
Tomy Tutor
Software for the Tomy Tutor computer. The Tutor was a computer system based around the 9900. A Cassette based system with it’s own BASIC and game cartridges. Known as the Pyuta in Japan and Grandstand Tutor in the UK.
TI99RESOURCES 
