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Date:      Thu, 8 Nov 2001 14:18:05 +0100 (CET)
From:      Nils Holland <nils@tisys.org>
To:        Stijn Hoop <stijn@win.tue.nl>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: dd and cat - Did I miss something?
Message-ID:  <20011108141503.P1041-100000@jodie.ncptiddische.net>
In-Reply-To: <20011108123825.E94394@pcwin002.win.tue.nl>

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On Thu, 8 Nov 2001, Stijn Hoop wrote:

> On Thu, Nov 08, 2001 at 12:16:57PM +0100, Nils Holland wrote:
> > Hi folks,
> >
> > I just wanted to copy a data CD. So I thought I'd first read it out. After
> > I had put the CD into my ATAPI CD-ROM drive, I issued the following
> > command:
> >
> > dd if=/dev/acd0a of=cdimage
> >
> > But it didn't work. I received a message saying "acd0a - Invalid
> > Argument".
> >
> > Next, I tried something different, namely:
> >
> > cat /dev/acd0a | dd of=cdimage
> >
> > and that did work! Any clues why my first attempt (only using dd and not
> > cat) failed?
>
> You should use /dev/acd0c - the 'c' partition means the whole disk. CD's
> don't have the concept of partitions, so there are no {a,b,...} partitions.
> Why the second attempt worked is a mystery to me...

Let's make some even bigger mystery out of it: dd if=/dev/acd0c of=cdimage
also fails, again with the "acd0c - Unknown Argument" message. Of course,
the second method still works after replacing acd0a with acd0c...

I'm running 4.4-Stable (as of last Saturday) here, and I think I remember
that some time in the past I had no such problems with dd. If anyone has
a clue what I'm doing wrong or what's going on here, I'd like to hear
about it!

Greetings
Nils

Nils Holland
Ti Systems - FreeBSD in Tiddische, Germany
http://www.tisys.org * nils@tisys.org


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