One of the guys trying my ImageDisk program is using an Adaptec 1542CF controller - he can read disks fine, however when he tries to write them, it gets an error during every write sector command. The status registers reported ar: SR0: 41 SR1: 04 SR2: 00 According to the NEC 765 datasheets: 41 means "Abnormal Termination of Command" "Execution of command was started, but not successfully finished" No other error indicators 04 means: "B3: Not used, this bit always low (0)", No other error indicators 00 means: No error indicators Looks like the controller in the Adaptec is using B3 as an error indicator, however I do not have any information on what this means ... Does anyone have technical information on the Adaptec controller and can tell me what this bit means? Regards, Dave -- dave04a (at) Dave Dunfield dunfield (dot) Firmware development services & tools: www.dunfield.com com Collector of vintage computing equipment: http://www.parse.com/~ddunfield/museum/index.html