Posts tagged with “Micro-Systems Software”


M-ZAL was a powerful disk-based editor assembler system for the TRS‑80 Model I and III. First introduced in 1981, M-ZAL (which stood for Modular Z80 Assembly Language) was written by Jeffrey Krantz and David Willen. It was sold by Computer Applications Unlimited (also known as CUA) for the price of $149.95.

Although expensive, M‑ZAL was one of the most advanced assemblers ever written for the TRS‑80 and it was used by many professional TRS‑80 developers.


DOSPLUS was one of the most popular of the disk operating systems available for the TRS‑80. Sold by Micro-Systems Software based in Hollywood (later Boca Raton), Florida, there were eventually versions of DOSPLUS for the TRS‑80 Model I, Model III, Model II, and Model 4.

The people behind Micro-Systems Software were Larry Studdard, Mark Lautenschlager, Steve Pagliarulo, and later Todd Tolhurst. According to a 1981 interview in 80-U.S.