William L. Maltby wrote: > It's not truly any relationship like that. It's just (in the old days) a > device ID selected on the cable by jumpers on the drive. The "control" > is nothing more than the IDE controller selecting either "0" or "1" > device ID for commands and data. The drive with the matching ID responds > while the other ignores. > > In todays world, cable select might provide the ID assignment. > > I'm not sure how "master" and "slave" came to be used in this scenario, > unless it had to do with BIOS boot processes back in the old days. Well, right you are. Scroll down to "Master and Slave Clarification": http://en.wikipedia.org/wiki/Integrated_Drive_Electronics I had been laboring under the impression that the 'master' drive controlled both drives on a single cable. Now I've learned the truth just in time for SATA to take over. :)