Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!munnari.oz.au!brolga!groucho!grl From: grl@brb.dmt.csiro.au (Greg Lehmann) Newsgroups: comp.periphs.scsi Subject: Re: Mixing sync and async SCSI devices Keywords: SCSI async sync Message-ID: Date: 23 Feb 91 03:23:45 GMT References: <1991Feb22.071227.26612@msen.com> <1991Feb22.201602.10592@dsd.es.com> Sender: news@brolga.cc.uq.oz.au Organization: Prentice Computer Centre, The University of Queensland, Australia. Lines: 19 Nntp-Posting-Host: groucho.brb.dmt.csiro.au courtney@tonto.es.com (Courtney Goeltzenleuchter) writes: >In article <1991Feb22.071227.26612@msen.com>, osm@msen.com (Owen Scott Medd) writes: >> If I mix sync and async SCSI devices on the same bus, do I force *all* >> devices on the bus to be dealt with as async devices? >No, you don't force all the devices to be async. It is the job of the initiator >(typically the host CPU) to negotiate with each target device whether or not the initiator will use syncronous transfers with that target. Agreed. SUN Microsystems won't support you if you have both sync and async devices on the same scsi chain. I suspect they want to sell more disk drives rather than there being any technical reason. Also from what I can gather all their tape drives are async. Doesn't make a lot of sense does it? -- Greg Lehmann, CSIRO Division of Manufacturing Technology, Telephone: +61 7 365 3877 c/- Dept. of Mining & Metallurgical Eng., Facsimile: +61 7 365 3711 The University of Queensland, QLD 4072. Internet: grl@brb.dmt.csiro.au