SYSPACK is a utility to compress DOS device drivers (as a rule,
*.SYS files). It may be used to make Your device drivers to eat less space on hard disk or seem to be more compact than they really are. I don't
want to convince anybody that it is of much use, however, compressed device drivers may be more convenient in some
cases.
A SYSPACKed device driver contains decompression code and compressed
data from original driver. When it is installed and receives from DOS initialization request it unpacks the data, restores original device
header and passes control to the device driver. From that time on the device driver behaves identically to its non-packed
original.