Date: Tue, 26 Jan 1999 22:05:10 +0100 From: Ollivier Robert <roberto@keltia.freenix.fr> To: "freebsd-hardware@freebsd.org" <freebsd-hardware@FreeBSD.ORG> Subject: Re: SCSI-3 vrs. ATA Message-ID: <19990126220510.B77068@keltia.freenix.fr> In-Reply-To: <199901261600.KAA22909@mail.netsys.hn>; from FreeBSD Questions on Tue, Jan 26, 1999 at 10:00:40AM -0500 References: <199901261600.KAA22909@mail.netsys.hn>
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According to FreeBSD Questions: > According to the Quantum Spec Sheet on the Web http://www.quantum. > com/products/hdd/fireball_se/datasheet.html > the speed for the ATA is 33.3MB/s and 20MB/s for the SCSI-3 The drive is not able to deliver data that fast. The best you can have now is around 12 MB/s (maybe a bit more but not much). Don't mistake the _bus_ speed with the _drive_ speed. ATA UDMA is a 33 MB/s bus and that seems to be near an UW drive (40 MB/s) but you won't never get that kind of speed from any drive. If you're using a single drive configuration, take either UDMA or SCSI. The only difference you may see is in CPU cycles consumption. SCSI will probably eat a bit less than ATA. If you begin to have more peripherals, like a CD-ROM or a second or third drive, go for SCSI. The disconnect & tagged commands features of SCSI will give you more performance on concurrent accesses than ATA. -- Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto@keltia.freenix.fr FreeBSD keltia.freenix.fr 3.0-CURRENT #69: Mon Jan 18 02:02:12 CET 1999 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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