Jasen Betts wrote in a message to Roy J. Tellason:

 JB>> The BIOS never skips COM-port numbers.  if you have  ports on 3F8
 JB>> 2F8  and 2E8  it'll number them com1 com2 com3  even though the
 JB>> last one (2E8) is the "com4" address.

 JB>> Dos follows the BIOS, MSD may be following the DOS naming of the
 JB>> ports.

 RJT> Hmm.  I wasn't aware of that.  I wonder why it shows up "right"
 RJT> in other software,  then

 JB> because other software doesn't use the BIOS for serial I/O
 JB> the same renumbering is done with printer ports too.

Makes sense.  And I've seen that bit with printer cards,  I can still
remember fiddling with one multi-i/o card that had a whole mess of jumpers
for which I had no info,  getting things showing up and then disappearing
as I fiddled with the settings.  I distinctly remember seeing the printer
port show up at 2 or 3 different addresses and still being called LPT1,  or
somesuch.

Some software just applied a different designation based on the actual
address, I guess.

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