First post, by auron
on my current batman's revenge setup, i am using a ~'92/93 UMC ISA i/o card because i don't have a cable with that rare pinout to fit the onboard serial header. it works and everything, but i've been wondering how does detection exactly work when there are now two SIO chips in the system. without the card plugged in all the ports are detected as FIFO capable in hwinfo, while COM1 is shown as a different type without FIFO when the card is plugged in. unlike later motherboards, there is no way to change the COM port addresses in BIOS, so wouldn't there be a conflict if both chips tried to use the same address? are performance differences between onboard and add-on SIOs conceivable?
this controller card has IDE as well and it can be jumpered on/off. however there is another jumper "HDC EXIST/NOT EXIST" and i'm assuming this stands for hard drive controller, but what does it do exactly? does it set the port to tertiary or quaternary as on sound cards?