From owner-freebsd-scsi Mon May 15 7:23:23 2000 Delivered-To: freebsd-scsi@freebsd.org Received: from exmta2.rjf.com (exmta2.rjf.com [170.12.31.84]) by hub.freebsd.org (Postfix) with ESMTP id E5B4137B740 for ; Mon, 15 May 2000 07:23:16 -0700 (PDT) (envelope-from ICartwright@IT.RJF.com) Received: by exmta2.rjf.com with Internet Mail Service (5.5.2448.0) id ; Mon, 15 May 2000 10:23:16 -0400 Message-ID: <6D5097D4B56AD31190D50008C7B1579B91204C@EXLAN5> From: Ian Cartwright To: "'freebsd-scsi@freebsd.org'" Subject: SCSI Speeds? Date: Mon, 15 May 2000 10:23:14 -0400 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2448.0) Content-Type: text/plain; charset="iso-8859-1" Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Hello, all. I have a question regarding the relative speeds of devices on a SCSI bus. I have two machines currently running FreeBSD. One is a P-200 with IDE and one is a PII-360 with both IDE and SCSI drives. I boot off the the SCSI bus on this machine. The IDE drives on both machines are UDMA-33. My SCSI drives are as follows (reported by FreeBSD on boot up): ID0: Fast SCSI2 HDD 10.00 MB Xfer (Synchronous), ID1: Ultra SCSI2 HDD 40.00 MB Xfer (Synchronous), ID2: SCSI2 CD-ROM 10.00 MB Xfer (Async), ID4: SCSI CD-Writer 3.300 MB Xfer (Async), ID5: SCSI2 Tape (Xfer not reported, Asynch). My question is this: why does it seem that the slower machine does disk access much faster? When I was installing these machines newfs wrote superblocks to the IDE drives much faster than to the SCSI drives, even though the Ultra SCSI drive (my FreeBSD drive) should theoretically be much faster... Many disk intensive operations seem to be faster on the IDE drives. Any ideas as to why this should be? Thanks! Ian Cartwright Senior Engineer Raymond James Associates icartwright@it.rjf.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message