Date: Tue, 04 Jan 2000 21:58:52 +0100 From: Olaf Hoyer <ohoyer@fbwi.fh-wilhelmshaven.de> To: hardware@FreeBSD.ORG Subject: Re: differences between SCSI and EIDE [was: wanna buy an EIDE harddisk... 5400 or 7200 for home use (noise)] Message-ID: <38725F0C.74C899BB@fbwi.fh-wilhelmshaven.de> References: <Pine.BSF.4.10.10001040917470.4553-100000@beppo.feral.com>
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Matthew Jacob schrieb: > > On Tue, 4 Jan 2000, Mitch Collinsworth wrote: > > > > > >anyway, thank you all for responding and sheading light on my > > >confusion. i'd always thought that scsi was the better way to > > >go, either fro the 'comercial' environment or the ever more > > >demanding 'home' environment. > > > > Well this is actually an interesting question. My salesman says the > > HDAs are the same in SCSI and EIDE drives, so reliability-wise there > > should be no difference. > > > words the drive logic has it's own queue management? And EIDE drives > > require their device drivers to perform all queue management and only > > initiate a command after the previous one has completed? > > > > Is the bottom line result of this that the SCSI drive has a much greater > > chance of servicing multiple processes during a single media revolution > > while the EIDE will frequently take multiple revolutions to service the > > same queue? Hi! Well, in corresponding HDDs, the mechanical parts are the same, only equipped with a different electronic controller. I remember the old Quantum Fireball series, that were clearly designed as a mass-market HDD. the SCSI interface was also a very cheap design, it was one of the slowest SCSI HDDs I've ever had. I suppose they only did it to have some product in the lower end of the portfolio. Anyway, it was much cheaper than the IBM or seagate drives targeted mainly at the server market. Nowadays you have the problem, that fews HDDs will share the same mechanical parts as of SCSI and IDE version, because most SCSI Hdds are designed for "heavy duty", therefore they are much more expensive in manufacturing of the interior. Ok, the Quantum Fireball plus KA is one of the few IDE Hdds that has server mechanisms inside, but I do not remember any cheap mass market HDDs that have some mechanical parts from the (far more expensive) server drives from the same company. (If someone could prove me wrong, I'd be happy to hear about the manufacturer ;-) ) Yes, drives like the barracuda ATA or so will of course share the same interior than the SCSI ones, but they are in a different pricing league... Anyway, the quality of the controller with its size of cache and the caching algorithms will definitively decide about the real performance. regards Olaf Hoyer To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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