> was there a technical reason for that, or could modern mainboards/BIOSes/OSes detect and correct for that? IIRC, there was a technical reason in that origina

> was there a technical reason for that, or could modern mainboards/BIOSes/OSes detect and correct for that? IIRC, there was a technical reason in that original mainboards lacked the circuitry to detect and correct for it (I think different mouse vs keyboard interrupts were involved?), and it would have been a extra x¢ on the BOM. But modern mainboards just use two of the same circuit and in fact do work fine if you swap them (tested just now, sample size of 1).