-----Original Message----- From: cctalk-admin@classiccmp.org@PEUSA On Behalf Of "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com> Sent: Sunday, January 12, 2003 12:02 AM To: cctalk(a)classiccmp.org Subject: RE: DOS 3.20 On Sat, 11 Jan 2003, John Willis wrote: The only difference that I found between them (except for certain highly customized OEM MS-DOS versions) was DRIVPARM. It is present in both, but is not documented in PC-DOS. It is incompatible with the IBM BIOS. (DRIVPARM worked with both PC-DOS and MS-DOS with three different generic clones; DRIVPARM would not work with either MS-DOS nor PC-DOS on real IBM AT and PS/2 (model 50?)) Some OEMs included the "technical reference manual" as appendix to their MS-DOS manual. IBM sold it as a separate book after 2.00.