Date: Tue, 30 Jul 2002 10:58:24 -0700 From: "Cliff L. Biffle" <cbiffle@safety.net> To: Jason Baker <jbaker@cs.utah.edu> Cc: multimedia@FreeBSD.ORG Subject: Re: PhotoCD: ata/acd mount issue, data overrun with lockup Message-ID: <200207301058.24713.cbiffle@safety.net> In-Reply-To: <6zheihp0rp.fsf@nephi.cs.utah.edu> References: <87d6tcgfan.fsf@thanatos.shenton.org> <6zheihp0rp.fsf@nephi.cs.utah.edu>
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On Tuesday 30 July 2002 10:46 am, Jason Baker wrote: > Ah, I had the same problem when I tried to create my own multisession > cd. What the hell does `-s <non-zero>' do exactly? Does it mount the > combined filesystem of that session and all previous ones, or just the > filesystem on that particular track. Does freebsd read multisession > discs at all? Many multi-session discs are formatted in such a way as to be=20 backwards-compatible with audio CDs: the data track that gets used by def= ault=20 is the outermost track on the disc (where CD sectors and tracks are both=20 numbered out from the hub). Audio CDs, by contrast, always start at sect= or=20 0. Thus, you can have an 'Enhanced CD', where a 'dumb' CD player plays t= he=20 audio at sector 0, but a computer reads the outermost track (assuming it'= s=20 data), which the audio CD player will avoid. The -s option on mount_cd9660 allows you to control this behavior. In th= e=20 case of the PhotoCD above, it sounds like there's an outermost data track= =20 that's either corrupted, mismarked, or just not ISO-9660 (god forbid). T= hus=20 the default behavior (mounting the outermost track) fails. Using -s 0=20 attempts to mount an ISO-9660 filesystem starting at sector 0 of the disc= =20 (innermost). Likewise, using -s 1 would start on sector 1, and so forth=20 (where CD-ROM sectors are 2048 bytes).=20 Unless I'm mistaken, the -s x option doesn't let you mount a specific ses= sion=20 unless you know its starting sector. However, I don't know of a good way= to=20 determine the starting sector -- is there a good FreeBSD tool for reading= the=20 TOC information? -Cliff L. Biffle To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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