Date: Wed, 22 Mar 1995 00:41:56 -0800 (PST) From: Poul-Henning Kamp <phk@ref.tfs.com> To: hackers@FreeBSD.org Cc: faq@FreeBSD.org Subject: Why IDE is bad Message-ID: <199503220841.AAA04565@ref.tfs.com>
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I just made a simple test, this shows why IDE is inferior to SCSI for FreeBSD: Western Digital 540 Caviar EIDE disk on IDE controller: ------------------------------------------------------- dd if=/dev/rwd0d of=/dev/null bs=64k count=8253 8253+0 records in 8253+0 records out 540868608 bytes transferred in 240 secs (2253619 bytes/sec) Here is what "systat" tells me: 2.0%Sys 82.0%Intr 0.5%User 0.0%Nice 15.6%Idle | | | | | | | | | | =+++++++++++++++++++++++++++++++++++++++++ Quantum Empire 2100 SCSI-II disk on VL-buslogic controller: ------------------------------------------------------------- dd if=/dev/rsd0d of=/dev/null bs=64k count=8253 8253+0 records in 8253+0 records out 540868608 bytes transferred in 110 secs (4916987 bytes/sec) Here is what "systat" tells me: 5.6%Sys 20.6%Intr 0.2%User 0.0%Nice 73.6%Idle | | | | | | | | | | ===++++++++++ CONCLUSION: ----------- The SCSI-controller transfers twice as much data in the same time, and uses only 25% of the CPU resources the IDE-controller needs. -- Poul-Henning Kamp <phk@login.dknet.dk> -- TRW Financial Systems, Inc. 'All relevant people are pertinent' && 'All rude people are impertinent' => 'no rude people are relevant'
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