From owner-freebsd-questions@FreeBSD.ORG Mon Feb 9 15:47:33 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4C2E716A4CE for ; Mon, 9 Feb 2004 15:47:33 -0800 (PST) Received: from smtp.covadmail.net (mx05.covadmail.net [63.65.120.65]) by mx1.FreeBSD.org (Postfix) with SMTP id E962C43D2F for ; Mon, 9 Feb 2004 15:47:32 -0800 (PST) (envelope-from strick@covad.net) Received: (covad.net 1424 invoked from network); 9 Feb 2004 23:47:27 -0000 Received: from unknown (HELO mist.nodomain) (strick@covad.net@67.101.99.150) by sun-qmail17 with SMTP; 9 Feb 2004 23:47:27 -0000 Received: from mist.nodomain (localhost [127.0.0.1]) by mist.nodomain (8.12.9p2/8.12.9) with ESMTP id i19NlUEp000719; Mon, 9 Feb 2004 15:47:30 -0800 (PST) (envelope-from dan@mist.nodomain) Received: (from dan@localhost) by mist.nodomain (8.12.9p2/8.12.9/Submit) id i19NlTRV000718; Mon, 9 Feb 2004 15:47:29 -0800 (PST) (envelope-from dan) Date: Mon, 9 Feb 2004 15:47:29 -0800 (PST) From: Dan Strick Message-Id: <200402092347.i19NlTRV000718@mist.nodomain> To: freebsd-questions@freebsd.org cc: dan@mist.nodomain cc: freebsd-hardware@freebsd.org Subject: short read from CD-RW X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Feb 2004 23:47:33 -0000 I just wrote an iso image to a virgin CD-RW with the following command: burncd -f /dev/acd0c -s 24 data 5.2.1-RC-i386-disc1.iso fixate and the burncd program said: next writeable LBA 0 writing from file 5.2.1-RC-i386-disc1.iso size 657024 KB written this track 657024 KB (100%) total 657024 KB fixating CD, please wait.. which is consistent with the iso image file size = 672792576 bytes = 657024 KB = 328512 2KB records. When I read the data back in from the CD with this command: dd if=/dev/acd0c of=xxx bs=2k the dd program says: dd: /dev/acd0c: Input/output error 328510+0 records in 328510+0 records out 672788480 bytes transferred in 252.669511 secs (2662721 bytes/sec) which is consistent with the xxx file size = 672788480 bytes = 328510 2KB records. Note that this is 4KB short of the expected file size. The acd driver produced this error message on the console: acd0: READ_BIG - MEDIUM ERROR asc=0x11 ascq=0x05 error=0x00 Recent SCSI standards further explain asc=0x11 ascq=0x05 as meaning "L-EC UNCORRECTABLE ERROR" and "L-EC" as "Layered Error Correction". I don't believe for a second that my CD medium just happened to have a bad sector at the very end of the iso disk image. Could this be a hardware glitch? Could the error message be incorrect? Is a driver bug involved? Notes: 1) I am running FreeBSD 4.9-RELEASE. 2) The CD-writer is a SAMSUNG SM-352B. 3) I get similar errors (not sure of the ascq) when any of my CD drives (both ATA and SCSI) try to read the first blank sector at the end of a CD-R (should be a short read or EOF). Dan Strick strick@covad.net