The PCjr that I kept for a while at my desk at IBM had a parallel port sidecar that was not detected by the BIOS during the initial cold boot. On that machine if I power cycled the machine the sidecar would then show up. To get around this problem I wrote a little debug script which just shoved the necessary bytes into the BIOS RAM area to indicate a parallel port was there.
The modem slot and the diskette slot both have dedicated "card select" lines so that the hardware/BIOS can detect the presence of the card. The sidecars do not have this feature. The BIOS must be testing for the presence of the parallel port by just poking at the ports. It is possible that on this old hardware there is a problem that can be cleared by booting.
Mike
FTPSRV and PCjr.
Re: FTPSRV and PCjr.
Perhaps some hardware is slower than other hardware. Could you be so good as to share the proper debug script?