Date: Fri, 30 May 1997 22:07:35 +1000 From: Stephen McKay <syssgm@dtir.qld.gov.au> To: freebsd-chat@freebsd.org Subject: Re: IDE or Ultra SCSI Message-ID: <199705301207.WAA15894@ogre.dtir.qld.gov.au> In-Reply-To: <19970530092929.CP11088@uriah.heep.sax.de> from J Wunsch at "Fri, 30 May 1997 07:29:29 %2B0000" References: <199705300343.XAA01738@federation.addy.com> <19970530092929.CP11088@uriah.heep.sax.de>
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On Friday, 30th May 1997, J Wunsch wrote: >As Francisco Reyes wrote: > >> I have been agonizing for a few days trying to decide whether to get >> IDE or Ultra SCSI. > >IDE is in theory as fast as SCSI. However, we don't support busmaster >DMA for IDE yet, and thus you eat up valuable CPU cycles with an IDE >drive, that could be spent better in serving processes on a >multiprocessing system. Is IDE (in theory) really as good? I understood that only one outstanding command was possible with IDE, meaning only one disk could be active at a time, versus many simultaneous commands with SCSI. Am I out of date? >``Ultra'' is more of a marketing gag than real value, it just means >``use double the clock rate, and allow for only half the cable >length''. On the other hand, Ultra Wide is where it's all going. Or so it looks to me. At least until that FireWire stuff is cheap. >> The difference in price betwen IDE and Ultra is about $700. Is it worth >> it? > >Why is it so much? I ask this often, hoping to have someone tell me it is not so. It is all to do with volume and margins for middle men. Fewer SCSI disks sold == higher prices. For example, I could go to a nearby computer shop and buy a 6Gb IDE disk for AU$600, or a 4Gb SCSI3 disk for AU$1100. That's nearly 3 times the cost per byte. I have no reason to believe that either is better quality than the other. What a downer. Or I could buy an 8x SCSI CD-ROM for twice the price of the same model drive with IDE interface. Sigh. So I have to keep telling myself what an investment in brain cells I have with SCSI, how it always works (well it does for me), and how every IDE system that I've tried to put 2 disks in, or take one drive out of, has been such a pain that I've given up. Then I calculate my hourly rate into the equation... Even so, I'm not sure if I'll give in this time round and turn to the dark side. The lure of cheap equipment! :-/ Stephen.
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