I/O base address
|IBM Printer Adapter||378||7|
|IBM Monochrome Display and Printer Adapter (MDA)||3BC||7|
|1.||Interrupt generation on parallel ports is normally disabled. Even when DOS prints to a parallel printer, it doesn't enable the interrupt 7 generation for the parallel port that the printer is attached to. Only specialist programs will enable the interrupt 7 generation on a parallel port.|
|2.||For there to be a problem, all of the following would need to be true:
* Program/TSR A running - using parallel port at 378 - has enabled interrupt generation on that port.
* Program/TSR B running - using parallel port at 3BC - has enabled interrupt generation on that port.
* Both of those programs/TSRs running at the same time.