Date: Tue, 20 May 2003 19:55:25 -0500 From: David Kelly <dkelly@HiWAAY.net> To: Eduardo Viruena Silva <mrspock@esfm.ipn.mx> Cc: FreeBSD-Questions@freebsd.org Subject: Re: Creating a bin or ISO image of a CD?? Message-ID: <200305201955.25530.dkelly@HiWAAY.net> In-Reply-To: <20030519200918.U95244@Gina.esfm.ipn.mx> References: <Pine.GSO.4.44L0.0305191912530.23582-100000@shell.core.com> <200305191951.40320.dkelly@HiWAAY.net> <20030519200918.U95244@Gina.esfm.ipn.mx>
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On Monday 19 May 2003 08:14 pm, Eduardo Viruena Silva wrote: > On Mon, 19 May 2003, David Kelly wrote: > > > > Some CDROM drives read the CD one block short. Makes it difficult > > to use raw tools to verify after write. > > try: > > dd if=/dev/acd0c of=my_image bs=2352 > > > what version of FreeBSD are you using? > if you are using versions 4.x you can make: That's not the same problem. Some CDROM mechanisms on reaching end of media report the situation along with the last block of data read. Others do not report the end has been reached until an attempt has been made to read past it. This is a common issue with tape drives too. If your drive doesn't report EOM when FreeBSD expects, and/or is not handled properly with a quirk table entry, then you can not read an identical-length ISO image off the disk as the image you wrote. 2048 is the proper block size when reading ISO-9660 CD's, altho it really shouldn't matter. -- David Kelly N4HHE, dkelly@hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system.
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