Xref: utzoo comp.sys.atari.st:37513 comp.sys.atari.st.tech:2096 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uwm.edu!rutgers!gatech!prism!mailer.cc.fsu.edu!nu!boyd From: boyd@nu.cs.fsu.edu (Mickey Boyd) Newsgroups: comp.sys.atari.st,comp.sys.atari.st.tech Subject: Re: Weird TT hard disk thingy Message-ID: <1991Apr24.081643.28248@mailer.cc.fsu.edu> Date: 24 Apr 91 12:31:11 GMT References: <1991Apr16.195300.1906@jato.jpl.nasa.gov> <1991Apr17.154845.29875@newcastle.ac.uk> <2910@atari.UUCP> Reply-To: boyd@nu.cs.fsu.edu Organization: Florida State Universiy Computer Science Department Lines: 44 In article <2910@atari.UUCP>, apratt@atari.UUCP (Allan Pratt) writes: >D.C.Halliday@newcastle.ac.uk (Dave Halliday) writes: > >The fatal flaw in your reasoning is that you think since both drives are >SCSI drives, they should have different SCSI unit numbers. What's actually >happening as far as the TT is concerned is that you have one SCSI drive and >one ACSI drive. The Supra drive is connected through a controller which >lets you plug the SCSI drive into the ACSI bus. The controller, in >essence, creates a tiny SCSI bus between it and the drive you connect to >it. This controller will only control one unit, and it has to be SCSI unit >0. My reasoning is fine, thank you. Yes, what you describe above is intuitively obvious after knowing that both drives needed to be set to 0. What is less obvious is why the Supra HAD to be set to 0. My ICD host adaptor will allow me to set the SCSI device id to whatever I want, and will still find the drive at boot time. I can hook multiple drives up to it, etc. Thus, I make the following assertion: there are two logically seperate busses on the TT (which concern fixed disks): a pure SCSI and an ASCI. Each is independent in the sense of SCSI device id numbers, so each can have a device 0 without conflict. My question (based on this assertion) is this: Why did the Supra drive _require_ SCSI id 0? It was the only device on that "bus"? In other words, do the SCSI id numbers on a bus have to start with 0, then increment by one? Could I have a device 0, then a device 4? If not, why? This has been successfully done by both Supra and ICD (and Atari, I thought). If so, then is the restriction only on the first SCSI device (ie does a device 0 have to exist, but other devices need not be sequentially numbered)? Another way to look at the question is this: What need be considered when hooking up multiple ASCI devices (consisting of host adaptor and SCSI device) to the TT? How must the SCSI id numbers be picked for all drives to work? It is inexcusable that this information was not included in the TT manual. For example, my hard disk was set to SCSI id 1 when I bought it. Thus, were I to get a TT (and without the benifit of helping my friend) I would not be able to get the damn thing to work without a phone call to Atari. Since this computer is a logical upgrade from the ST architecture, all information needed to "upgrade" should be included in the manual!!!!!! -- ---------------------------------+------------------------------------- Mickey R. Boyd | "Kirk to Enterprise. All clear FSU Computer Science | down here. Beam down Technical Support Group | yeoman Rand and a six-pack . ." email: boyd@fsucs.cs.fsu.edu | ---------------------------------+-------------------------------------