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Xref: sserve comp.os.386bsd.questions:5449 comp.periphs.scsi:14260 Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!swrinde!news.dell.com!natinst.com!hrd769.brooks.af.mil!hrd769.brooks.af.mil!not-for-mail From: burgess@hrd769.brooks.af.mil (Dave Burgess) Newsgroups: comp.os.386bsd.questions,comp.periphs.scsi Subject: Re: CDs and SCSI Date: 28 Sep 1993 08:58:35 -0500 Organization: Armstrong Laboratory, Brooks AFB, TX Lines: 25 Message-ID: <289fup$967@hrd769.brooks.af.mil> References: <CE29yI.IKt@festival.ed.ac.uk> <CE2AF7.AA@veda.is> NNTP-Posting-Host: hrd769.brooks.af.mil In article <CE2AF7.AA@veda.is> adam@veda.is (Adam David) writes: }richard@castle.ed.ac.uk (Richard Tobin) writes: } }>There seem to be numerous CD rom drives on sale that are sold with }>SCSI adaptors much cheaper than the adaptors supported by BSD (Adaptec }>etc). What is the difference between these adaptors and the supported }>ones? Obviously they may require different drivers, but are the }>adaptors themselves inherently less capable? } }You might find that they are not DMA busmasters, so you could end up using }more CPU cycles pushing all that data around. You might also find them slower }for this or any other number of reasons. Wasn't someone working on an ST-02 }driver? } Isn't the amount of CPU used for these types of transfers something like 17 cycles + 2/byte? At 20Mhz, that is a herd of data in a second. It seems to me that Glen Overby at plain.nodak.edu was working on it. I haven't heard much on it an a while. -- ------ TSgt Dave Burgess NCOIC AL/Management Information Systems Office Brooks AFB, TX