Zenith MS-DOS Programmer's Utility Pack DOS

The Zenith Programmer's Utility Pack for MS-DOS contains source code and compiler utilities needed for building an MS-DOS BIOS (IO.SYS file) for use with the Zenith Z-100 (not IBM hardware compatible), the Zenith Z-100 PC (IBM hardware compatible), and the Zenith Z-100 PC running in Z-100 compatibility mode.

Zortech C++ DOS

The Zortech C++ Compiler was a high performance compiler for MS-DOS, OS/2, and Windows that implemented the AT&T C++ 2.0 specifications. It competed strongly against Microsoft C and Watcom C. It later became the Symantec C++ compiler. It was also the first commercial compiler that natively supported Microsoft Windows.