Spconv is a utility to convert between various snapshot formats. Snapshot
files  are created by various spectrum emulators. SPCONV converts between
.SNA, .SP, .Z80, .PRG, .ACH, .SNX, .SIT and .ZX files.

Wildcards for the infile or outfile parameters are not accepted, an error
message  is  displayed  if  either  *  or  ?  is found in one or both the
filenames. The outfile parameter is either a full filename  or  only  the
suffix  .SNA, .SP,  .Z80, .PRG,  .ACH, .SNX,  .SIT or .ZX.  The prefix is
taken from the first parameter in that case.