"Jason Willgruber" <roblwill(a)usaor.net> asks:
Wasn't a 5 or 10 MB FH HD available for the PC?
Not from IBM. The 63 W power supply in the PC was not really adequate
for a hard drive. Several people I knew bought aftermarket hard drives
and had their power supplies fail.
IBM put a higher-rated supply into the XT so that it could reliably support
a hard drive.