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Date:      28 Nov 2002 12:56:11 +1030
From:      "Daniel O'Connor" <doconnor@gsoft.com.au>
To:        Dan Lukes <dan@obluda.cz>
Cc:        freebsd-stable@FreeBSD.ORG, sos@FreeBSD.ORG
Subject:   Re: Mounting a mixed-mode CD
Message-ID:  <1038450371.19350.36.camel@chowder.gsoft.com.au>
In-Reply-To: <3DE515A6.4070403@obluda.cz>
References:  <1038378879.10876.4.camel@chowder.gsoft.com.au> <20021127090013.GA58575@falcon.net.informatik.tu-muench> <1038388486.10876.45.camel@chowder.gsoft.com.au> <3DE515A6.4070403@obluda.cz>

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On Thu, 2002-11-28 at 05:27, Dan Lukes wrote:
> 	The '-s' option shouldn't be necesarry as the default value for it is 
> the starting sector of last data track on CD - e.g. 306572 for your CD, 
> but it's not error to specify it by hand.

Yeah, that was my expectation too.

See other emails about this where if I use atapicam and mount the device
through cd0c it Just Works (tm), so I guess it is a shortcoming in the
acd driver..?

> 	Just for sure - not every data track must be in an ISO9960 format. If 
> you are in doubth, you can extract the blocks 16-100 of data track (e.g. 
> 84 block starting at 306572+16 of your CD) by
> dd if=/dev/acd0c of=cd.bin bs=2048 count=84 skip=306588
> One of 84 extracted blocks saved in cd.bin file should start with byte 
> 0x01 followed by "CD001" or "CDROM" signature - otherwise, it's not data 
> track suitable for cd9660 mounting.

[chowder 12:50] ~ >dd if=/dev/acd0c of=cd.bin bs=2048 count=84
skip=306588
dd: /dev/acd0c: Invalid argument
0+0 records in
0+0 records out
0 bytes transferred in 0.000318 secs (0 bytes/sec)

Mmm, curious.

However..
[chowder 12:52] ~ >dd if=/dev/acd0t17 of=cd.bin bs=2048 count=84
84+0 records in
84+0 records out
172032 bytes transferred in 0.156220 secs (1101217 bytes/sec)
[chowder 12:52] ~ >hexdump -C cd.bin | less                     
00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
00008000  01 43 44 30 30 31 01 00  20 20 20 20 20 20 20 20  |.CD001..        |
00008010  20 20 20 20 20 20 20 20  20 20 20 20 20 20 20 20  |                |
00008020  20 20 20 20 20 20 20 20  32 30 30 32 5f 31 30 5f  |        2002_10_|
00008030  32 37 20 20 20 20 20 20  20 20 20 20 20 20 20 20  |27              |

Hmmm...

Maybe it's blowing up because it looks at the first track and sees data,
so the block size it uses to check things with is 2352, and when the
mount code tries to read the disk it wants to use 2048.

Although, in that case I would expect mounting acd0t17 would work, but
it doesn't.

Not that I have much disk driver clue :)

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 9A8C 569F 685A D928 5140  AE4B 319B 41F4 5D17 FDD5


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