The Solid State Software module was a ROM cartridge for use with the Texas Instruments TI-58 and TI-59 series of programmable calculators introduced in 1977.
One Solid State Software module, the Master Library Module, was included with the calculator and contained 25 pre-programmed routines, including a simple game called Hi-Lo. Some additional modules were available to extend the calculator with additional routines, with names like Surveying, Business Decision and Farming. Each module contained up to 5 KB of software and the standard price was $40. Small label cards were included with the modules to indicate the necessary keys to use for the different routines, and these could be placed in a slot below the screen.
As well as the Solid State Software modules, the TI-59 only also offered the ability to store routines on small magnetic cards that were the same size as the label cards that came with the Solid State Software modules.
A thermal printer was available from Texas Instruments that also acted as a docking station.
The TI-58 and TI-59 series were popular, and a number of user groups were setup. However, both series were discontinued in 1983, and subsequent models no longer used ROM cartridges for storage.