The TIOS is the official, standard operating system for the TI-83+ series of calculators (including the TI-83+ and TI-84+ and the respective Silver Editions of each). The vast majority of programs for such calculators run on top of the TIOS, or on top of some subsidiary program that runs from the TIOS, and thereby implicitly depend on its functionality. However, some people have researched writing alternative operating system code and sending it to the calculator to replace the TIOS. Several such alternative operating systems are available on the Web, though most of them are not yet at a production stage of development.
List of alternative operating systems
- CEPTIC, by Michael Vincent: a Control and Execute Program for TI Calculators. The current version of CEPTIC only runs on the TI-83+ SE, but can be modified to run on the TI-83+. Assembly source is available, but actually using the OS in its present state is considered non-practical, and the project has been discontinued for various reasons.
- PongOS, by FloppusMaximus: a simple, proof-of-concept system whose namesake feature is an embedded Pong game. Some other system utilities, mostly inspired by Dan Englender's Calcsys, are also available in PongOS, including a hex editor, memory mover (with flash capability), flash sector eraser, and port monitor. Link support is not provided.
- Vera, by several members of different programming groups: dubbed the "true calc lover's OS" on the website. Vera is intended to consist of a very basic kernel which can be easily extended to include desired features. Vera is still in the planning stage as of 2006-03-27.
- CSX, by Sean McLaughlin: a command-line-based operating system with a screen layout similar to that of the TI-89 calculators. CSX provides a simple filesystem, send and receive of files over a link cable, hex editing of memory, and running of Z80 machine code programs.
- Nostalgy, by XDG Kat-Productions: an unofficial project by certain members of XDG Kat-Productions. No working demo is available, but development is reportedly still underway, albeit very slowly.