CompuServe Messages

The PC can handle two parallel and two serial ports simply because they were pre-allocated address space in the port address map. Even this leads to problems because the ports share interrupts, leading to virtually un-diagnosable and un-repairable bugs, short of answers like "don't use those two ports at the same time." "Adding other stuff can be challenging for anyone." No kidding, even a savvy PC person might take several days effort to figure out a conflict between IRQs, port addresses, ROM maps, DOS extenders, network cards, SCSI cards, video cards – all that "other stuff". In other words, adding anything to a PC often leads to emergency calls to either a dealer or a diagnostician with PC experience.