Date: Sun, 13 Sep 1998 23:43:39 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: tom@uniserve.com (Tom) Cc: gpalmer@FreeBSD.ORG, irc@cooltime.simplenet.com, freebsd-current@FreeBSD.ORG Subject: Re: Download of FreeBSD 3.0-SNAP Message-ID: <199809132343.QAA23937@usr04.primenet.com> In-Reply-To: <Pine.BSF.3.96.980913101538.21866A-100000@shell.uniserve.ca> from "Tom" at Sep 13, 98 10:17:17 am
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> > Over fast local links, the speed of your disk often affects the speed > > of the install more than network issues. > > If 200 KB/s is too much for your disks, it is time to join the late > '80s and get new disks. Note that even some brand new disks will bottleneck you. FreeBSD no longer does elevator sorts on data pending output, relying instead on the disk hardware to be smarter about this, especially given the likelihood that the drive is lying about its pysical geometry, making it unlikely that any sort you could do would result in an optimization. While this is fine for disks that can support multiple outstanding commands pending simultaneously (giving them something to sort), it is less of a good idea for stupid disks that must be sent commands serially. Like, oh, say, E/IDE disks. The FreeBSD E/IDE driver supports queued tagged commands, but few E/IDE drives have this capability (in fact, I am not aware of *any* that support this portion of the spec.). It should be noted that some SCSI devices don't support tagged command queuing, either (but we don't buy those, since they are in the minority). So new disks are not necessarily the answer. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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