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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!simtel!chi-news.cic.net!io.org!torfree!rogers.com!mail.rogers.com!usenet From: blau@mail.rogers.com (Benjamin Lau) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Q. Drive Spec Defaults and Impacts? Date: Sun, 19 Nov 1995 00:20:37 GMT Organization: Rogers Communications Inc. Lines: 54 Message-ID: <48lsre$162@mail.Rogers.Com> NNTP-Posting-Host: 142.146.58.8 X-Newsreader: Forte Free Agent 1.0.82 Hi, Please correct me if I am wrong in any aspect... During the initial FBSD (2.0.5/2.1) installation from the floopy disk, all the disks are labled (by disklabel) using some default parameters, such as RPM, the device name etc. These defaults values can be retrieved, after the installation, by using '/sbin/disklabel -r sd<x>'. What I found is that, on the first SCSI drive where I put my system files, the RPM is defaulted to 3600RPM and the other two SCSI drives on the same system are defaulted to 0RPM. And in fact, when I do a '/sbin/disklabel' on those drives, it gives a warning about that "zero RPM". BTW, all the drives run at 7200RPM. What I am wondering is that, will this 3,600RPM or Zero-RPM factor or other default parameters affect the performance of the drives? As far as I know, these drives are working fine even though they are burned with those defaults. But does 'newfs' or 'mkfs' use those parameters to fine-tune or optimize the location of disk blocks? If the drive spec's have to be matched in order to gain the full and useful speed, is there or is it possible to have an option from the "installation screen" to let users to specify those parameters? Do we need to modify those parameters to match the exact same spec' of the drive and redo newfs? and how? I understand that we can define an entry in /etc/disktab to specify all those parameters. However, this is only possible after the installation and when we are adding a new disk to the system. Also, I am using a trick that I remembered from previous posts to avoid the installation to complain about "wrong geometry" of the drives ie. put a small DOS partition on each drive and let the install to fingure out the geometry. BTW, I'm using Adaptec with 'extended BIOS translation ON' and I found no difference when that is 'OFF'. Will this also affect the performance of the drive 'cause newfs, disklabel may get the 'translated' disk parameters? I'm becomming a little bit confused... Thanks for any comments, help and suggestions. Best Regards, Ben blau@mail.rgoers.com