Joe Wingbermuehle’s Ion was the first major shell for the TI-83+. Its library functions now represent something of a lowest common denominator for support provided by shells. These functions are available to programs using the identifying program headers for Ion, MirageOS and Doors CS.

• iVersion - Return the version of Ion emulated by these routines (1.6)
• iRandom - Return a random integer within given bounds.
• iPutSprite - Render a small (8-pixel-wide) sprite into the graph buffer.
• iLargeSprite - Render a large sprite into the graph buffer.
• iFastCopy - Quickly copy the graph buffer to the LCD. Nspire- and TI Presenter-compatible.
• iDetect - Similar to ChkFindSym.
• iDecompress - Decompress bit-packed data.
• iGetPixel - Get graph buffer offset and mask for a given pixel.