From owner-freebsd-hardware Fri Mar 12 8: 9:27 1999 Delivered-To: freebsd-hardware@freebsd.org Received: from mag.ik.nu (mail.smulweb.nl [194.158.187.79]) by hub.freebsd.org (Postfix) with ESMTP id DF699153F5 for ; Fri, 12 Mar 1999 08:08:24 -0800 (PST) (envelope-from e@ik.nu) Received: (from edwinm@localhost) by mag.ik.nu (8.9.1/8.9.1) id RAA12613 for hardware@FreeBSD.ORG; Fri, 12 Mar 1999 17:08:07 +0100 (CET) From: Edwin Mons Message-Id: <199903121608.RAA12613@mag.ik.nu> Subject: SCSI ZIP slow transfers To: hardware@FreeBSD.ORG Date: Fri, 12 Mar 1999 17:08:06 +0100 (CET) X-Mailer: ELM [version 2.4ME+ PL38 (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 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. Regards, Edwin Mons Edwin Mons | ...and the LART shall reign, and the e@ik.nu | daemons shall conquer the evil fortresses http://www.mons.net | of the beast of NT and their leagues of FreeBSD - the power to serve | management and MicroDrones... To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message