From owner-freebsd-hardware Fri Mar 12 9:19:30 1999 Delivered-To: freebsd-hardware@freebsd.org Received: from panzer.plutotech.com (panzer.plutotech.com [206.168.67.125]) by hub.freebsd.org (Postfix) with ESMTP id B949E14CAC for ; Fri, 12 Mar 1999 09:19:22 -0800 (PST) (envelope-from ken@panzer.plutotech.com) Received: (from ken@localhost) by panzer.plutotech.com (8.9.3/8.8.5) id KAA32574; Fri, 12 Mar 1999 10:18:51 -0700 (MST) From: "Kenneth D. Merry" Message-Id: <199903121718.KAA32574@panzer.plutotech.com> Subject: Re: SCSI ZIP slow transfers In-Reply-To: <199903121608.RAA12613@mag.ik.nu> from Edwin Mons at "Mar 12, 1999 5: 8: 6 pm" To: e@ik.nu (Edwin Mons) Date: Fri, 12 Mar 1999 10:18:51 -0700 (MST) Cc: hardware@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL43 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Edwin Mons wrote... > Hi. > > I use FreeBSD 3.1-RELEASE at home, and have a SCSI ZIP drive attached > to an NCR-810 controller. When reading or writing DOS disks, I can read > and write at 97 KB/s max. If the disk is a UFS ZIP, transfer speeds of > 400 KB/s can be reached, but if I dd the raw data from either one of these > two disks, speed is reduced to 97 KB/s again. After enabling CDB debugging > for the ZIP drive I noticed that when accessing the UFS ZIP data is read > in 64 KB blocks, while when reading raw data (with dd) or a DOS disk, the > blocksize is 4KB. > > Can anybody explain this to me? I more or less expected to see the 4 KB > blocksize when accessing the DOS partition (8 sector cluster layout), but > I can't explain the 4 KB blocks for raw reads. What arguments did you use with dd? Did you specify 64k blocks when reading from the raw device? Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message