Date: Thu, 13 Jan 2000 12:43:14 +1300 From: Joerg Micheel <joerg@cs.waikato.ac.nz> To: sthaug@nethelp.no Cc: grios@ddsecurity.com.br, ohoyer@fbwi.fh-wilhelmshaven.de, freebsd-hardware@freebsd.org, joerg@cs.waikato.ac.nz Subject: Re: hardware Message-ID: <20000113124314.I5228@cs.waikato.ac.nz> In-Reply-To: <72218.947717759@verdi.nethelp.no>; from sthaug@nethelp.no on Wed, Jan 12, 2000 at 11:55:59PM %2B0100 References: <387D0354.63159B8@ddsecurity.com.br> <72218.947717759@verdi.nethelp.no>
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On Wed, Jan 12, 2000 at 11:55:59PM +0100, sthaug@nethelp.no wrote: > > So i cannot understand, take a closer look: > > http://www.seagate.com/cda/products/discsales/marketing/detail/0,1121,43,00.shtml > > > > May anyone here explain me this ? > > As far as I can see, Seagate's specifications are somewhat conflicting, > or at the very least unclear. I'm looking at the "Performance" table from > > http://www.seagate.com/cda/products/discsales/enterprise/tech/0,1131,43,00.shtml > > Yes, it says "External (I/O) Transfer Rate (max) 80 MBytes/sec" - but this > is worthless since it obviously means transfer from the cache. The number > which is interesting is *sustained* transfer rate, at the outer and inner > part of the disk. > > (Compare with "Internal Transfer Rate (max) 264 Mbits/sec" - you'd need an > internal transfer rate of more than 640 Mbits/s to get a sustained 80 MB/s > from the outer part of the disk.) > > Even so, an *average* formatted transfer rate of 22.5 MB/s is rather good! FWIW, this is a 3.3-RELEASE system: da0: <SEAGATE ST150176LW 0002> Fixed Direct Access SCSI-2 device da0: 40.000MB/s transfers (20.000MHz, offset 8, 16bit), Tagged Queueing Enabled da0: 47702MB (97693755 512 byte sectors: 255H 63S/T 6081C) 48 [negara] (root) benchmarks/rawio/work # rawio /dev/rda0c Random read Sequential read Random write Sequential write ID K/sec /sec K/sec /sec K/sec /sec K/sec /sec anon 3556.7 220 5227.6 319 I can't perform any write tests, this drive is in use. Joerg -- Joerg B. Micheel Email: <joerg@cs.waikato.ac.nz> Waikato Applied Network Dynamics Phone: +64 7 8384794 The University of Waikato, CompScience Fax: +64 7 8384155 Private Bag 3105 Pager: +64 868 38222 Hamilton, New Zealand Plan: TINE and the DAG's To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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