Date: Fri, 21 Apr 2006 20:06:26 +0200 From: Ulrich Spoerlein <uspoerlein@gmail.com> To: current@freebsd.org Cc: sos@freebsd.org Subject: acd(4) and maximum read block size Message-ID: <20060421180626.GA28049@roadrunner.buck.local>
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--NzB8fVQJ5HfG6fxh Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable S=F8ren, group, I'm working on some improvements for recoverdisk[1] to handle optical media better. I found it an invaluable tool for recovering old CD-Rs. It also helps with newer DVDs, when your drive sucks wrt. error recovery. recoverdisk tries to read in 1MB, 64kB and SECTORSIZE chunks. This has the obvious drawback, that it can't really handle audio CDs or mode 2 CDs with a sectorsize of 2352. While this is easily fixed, the acd(4) driver seems to allow no reads greater than 128kB *for audio CDs*. While this is also not terrible, it results in roughly 700 error messages per CD, as all the 1MB (1046640 bytes, more precisely) chunks will fail. A side note: Accessing audio CDs via atapicam and dd(1) is completely impossible. Is the SCSI subsystem limited to multiple-of-512-blocksizes? [1] /usr/src/tools/tools/recoverdisk Ulrich Spoerlein --=20 PGP Key ID: 20FEE9DD Encrypted mail welcome! Fingerprint: AEC9 AF5E 01AC 4EE1 8F70 6CBD E76E 2227 20FE E9DD Which is worse: ignorance or apathy? Don't know. Don't care. --NzB8fVQJ5HfG6fxh Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.2 (FreeBSD) iD8DBQFESR8h524iJyD+6d0RAnoIAJ0fznHDGf8IS3hQKplfD21wcmTkhQCgs+b6 sBp2PvhNGD4pVq3IsbiBwcM= =NYGQ -----END PGP SIGNATURE----- --NzB8fVQJ5HfG6fxh--
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