RDMC is just a packer, so it packs a single file into another. It's based on DMC (Dynamic Markov Compression) algorithm, as created by
Gordon V. Carmack and Nigel S. Horspool, and implemented by Pierre Almeras (st0ne) on his winning entry for Hugi Size Compo #7.
The R comes from "Reiterative", because I've implemented a compression
idea, that involve that some parts of the file may be processed several times (that doesn't occur in the simple DMC implementations I've seen so
far).
RDMC needs a 386 or higher processor with FPU, and needs to alloc 4.4Mb
of RAM, so probably your equipment should have at least 8 Mb. These figures aren't too high for today's standars, where 128Mb computers are
quite common. It may run under DOS or Windows, thanks to WDOSX extender.