>>>>> "James A Robinson" writes:
>> I could be wrong but I think the first port is lp0.
> Well, I believe /dev/lp0 is the first port on XT machines, and lp1
> is the first on AT machines. At least on mine, when I cat something
> to /dev/lp0 I get nothing on my printer, but /dev/lp1 makes my
> printer show activity.
Not quite. The lp devices are numbered according to their i/o ports.
Thus lp0 is the lp device found on the original MDA, lp1 and lp2 are
the two ports located on the Multi-I/O boards or the motherboard.
There could also be a fourth port, because technically it is possible
to fit two video boards with additional printer ports into the system.
(IBM did reserve the ports in the i/o address space). It would have
made more sense to have lp0 numbered as lp2 because it is quite
uncommon but on the other hand ordering devices according to their i/o
space isn't stupid too.