The 99/4A had the benefit of an advanced 16-bit processor, but was tied down by its 8-bit bus and the brilliant, but bizarre use of memory mapped GROMs (Graphic Read Only Memory), with their own programming language (GPL - graphic programming language). It attracted a loyal cult fan base, especially after it was orphaned by TI. The TI99/4A is still a popular target of many PC based emulators.
Texas Instruments, despite its success in education, eventually retired from the home computer market.
wikipedia.org dumped 2003-03-17 with terodump