Hunter Systems – presumably the other part of the Hunter & Ready parting of the ways – has been commission by Intergraph Corp, Huntsville, Alabama to do a version of its XDOS product for the Clipper 32-bit chip set. There are several solutions to running MS-DOS programs under Unix on machines built around Intel iAPX-86 series microprocessors, but XDOS is designed to enable MS-DOS applications to execute fast on non-Intel processors – initially the 68000 family. Intergraph reckons that Clipper/ XDOS will offer MS-DOS performance significantly better than that on an AT. The key feature of XDOS is that it uses a binary compilation technique rather than software emulation. Binary compilation uses advanced optimising compiler techniques so that instead of using a source file written in C, Pascal or Fortran, a binary compiler operates on an executable binary file as its source. The output of the binary compiler is an executable binary that can be run on a variety of different computer architecture. XDOS consists of two parts – the binary compiler, which uses as its source 8086 binary code and generates executable binary code to run on the target microprocessor compilation needs to be done only once; and the XDOS PC interface library, which provides the connection between the MS-DOS environment and the target machine’s operating system. It is a complete emulation of the interface that an MS DOS program sees while it executes – MS-DOS, ROM BIOS and addressable hardware.
