Path: utzoo!utgpu!cunews!bnrgate!bnr-fos!bmers145!news From: sanjiv@bmers187.uucp (Sanjiv Khurana) Newsgroups: comp.periphs.scsi Subject: Reselection problem with Mac SCSI device Message-ID: <1990Oct17.173613.12989@bmers145.bnr.ca> Date: 17 Oct 90 17:36:13 GMT Sender: news@bmers145.bnr.ca Distribution: na Organization: Bell-Northern Research, Ottawa, Canada Lines: 29 Mac SCSI Expert Advice Needed ---------------------------- Subject: how to reselect the Mac after disconnection. The sequence of events on the SCSI bus is: Mac gets bus Mac selects device (ATN asserted) Mac issues IDENTIFY message Mac issues data transfer command Device issues "SAVE DATA POINTERS" message Device issues "DISCONNECT" message Device gets bus Device attempts to reselect Mac Mac ignores device completely The problem is how to make the Mac respond to reselection. I can poll the SCSI bus (using SCSIStat) but once I recognize that the device wants to reselect, how do I tell the Mac that I want to acknowledge the reselection? I need to assert the BSY line to acknowledge it, according to the SCSI standard. Once that's done, the device will take over again, and all's well. I am working on a Mac II with the old SCSI manager and system 6.0.5. Thanks for any advice... If possible, please respond via e-mail to "gbrown@bnr.ca" (bitnet) Gord Brown