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Date:      Sun, 22 Apr 2001 13:05:43 +0200 (CEST)
From:      Paul Herman <pherman@frenchfries.net>
To:        Schlenker <schlenke@fmi.uni-passau.de>
Cc:        <freebsd-questions@FreeBSD.ORG>
Subject:   Re: Duplicating Audio CDs
Message-ID:  <Pine.BSF.4.33.0104221255340.88695-100000@husten.security.at12.de>
In-Reply-To: <Pine.SOL.4.32.0104221231210.740-100000@bender.fmi.uni-passau.de>

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On Sun, 22 Apr 2001, Schlenker wrote:

> > I tried using /dev/acd0c (which is what the link points to) just in
> > case but it made no difference :(
>
> When using dd with a data cd, you must use the raw device e.g. /dev/racd0c

Just an aside:

While this is true for most Unicies, FreeBSD 4.x no longer uses block
devices, so AFAIK, there is no difference anymore.  They both require
block sized (512-byte) transfers.

 bash-2.04$ ls -l /dev/*acd0c  | more
 crw-r-----  2 root  operator  117,   2 Mar 31 23:38 /dev/acd0c
 crw-r-----  2 root  operator  117,   2 Mar 31 23:38 /dev/racd0c

 bash-2.04$ dd if=/dev/rad0s2c of=/dev/null bs=511 count=1
 dscheck(#ad/0x30002): b_bcount 511 is not on a sector boundary (ssize 512)
 dd: /dev/rad0s2c: Invalid argument
 0+0 records in
 0+0 records out
 0 bytes transferred in 0.001602 secs (0 bytes/sec)

 bash-2.04$ dd if=/dev/rad0s2c of=/dev/null bs=512 count=1
 1+0 records in
 1+0 records out
 512 bytes transferred in 0.020989 secs (24394 bytes/sec)

Same goes for /dev/ad0s2c.  This might be different for non-block
devices...

-Paul.


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