Date: Fri, 9 Jul 2004 16:43:41 -0400 From: Bill Moran <wmoran@potentialtech.com> To: Jean-Sebastien Roy <js@jeannot.org> Cc: freebsd-questions@freebsd.org Subject: Re: Silent errors when reading CDs Message-ID: <20040709164341.6b0d4523.wmoran@potentialtech.com> In-Reply-To: <40EEC01F.8030405@jeannot.org> References: <40EEC01F.8030405@jeannot.org>
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Jean-Sebastien Roy <js@jeannot.org> wrote: > Hi ! > > I'm currently using FreeBSD 4.10 on an HP D530 SFF. > The system is perfectly stable except for the following problem > I'm unable to understand : > > When I mount a cdrom (mount /cdrom), then calculate the MD5 hash > of a big file on a CD (md5 /cdrom/bigfile), the results are often random: > unmounting, mounting again and calculating again the MD5 often result in > a different value. What disturb me the most is that absolutely no errors > are reported in any log (no read errors for example). > > I thought the CDROM reader, a LITE-ON LTR-48327S PQS3, was the culprit, > so I replaced it with a PLEXTOR DVDR PX-712A and got the exact same results > (i.e. random MD5 values). I checked the RAM using memtest and got no > errors. The problem does not occur for files on the harddisk. > > hw.ata.atapi_dma is set since both drives support it and it seems to be > required for proper CD/DVD burning. The CD drive is the master on its > own ATA bus. > > Could someone provide me a hint on what to check next or how to fix this > problem ? > > Thank you very much in advance, I tried this out on my machine, which is completely different hardware/config than yours, and I could not reproduce the problem. It would seem to me that the problem is either hardware-specific or the result of the above-mentioned sysctl (my atapi_dma is turned off, and I'm too lazy to reboot to try it on) This question may be better suited for hackers@ -- Bill Moran Potential Technologies http://www.potentialtech.com
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