From: Warner Losh <imp@bsdimp.com>
To: Arthur Krewat <krewat@kilonet.net>
Cc: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] PDP-7 UNIX filesystem
Date: Fri, 25 Oct 2019 16:54:43 -0600 [thread overview]
Message-ID: <CANCZdfqkvkvwSePo_7nHX1cY0yvWchd-bua-037+4dG6TR5djw@mail.gmail.com> (raw)
In-Reply-To: <e86263e9-45f5-d0d6-ad62-95f70474138c@kilonet.net>
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On Fri, Oct 25, 2019, 3:35 PM Arthur Krewat <krewat@kilonet.net> wrote:
> On 10/25/2019 5:08 PM, Michael Kjörling wrote:
> > The only thing resembling "deprecation" of dd that I'm aware of is the
> > recommendation I saw many years ago to not use it to copy potentially
> > problematic storage media (for data recovery), but to use ddrescue for
> > that purpose instead. The reason for this is that with conv=noerror
> > (without which it'd simply abort if it encounters an I/O error), dd
> > would simply skip past data in the input that it can't read, but not
> > adjust any offsets in the output, which wreaks havoc with anything
> > where offsets matter (such as in file system metadata).
>
> Which is where conv=sync,noerror comes in. Of course, I have no freakin'
> idea what version of UNIX that came into being. ;)
>
Ddrescue tries multiple times with different sizes, which dd doesn't do.
Warner
art k.
>
>
>
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next prev parent reply other threads:[~2019-10-25 22:55 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 6:22 Angelo Papenhoff
2019-10-21 10:43 ` Abhinav Rajagopalan
2019-10-21 11:38 ` Abhinav Rajagopalan
2019-10-21 12:00 ` Thomas Paulsen
2019-10-21 13:31 ` Abhinav Rajagopalan
2019-10-22 18:07 ` Peter Jeremy
2019-10-23 0:07 ` Mary Ann Horton
2019-10-23 2:02 ` Kurt H Maier
2019-10-23 2:19 ` Larry McVoy
2019-10-23 8:34 ` Thomas Paulsen
2019-10-24 0:06 ` Warner Losh
2019-10-24 2:23 ` Michael Parson
2019-10-25 21:08 ` Michael Kjörling
2019-10-25 21:34 ` Arthur Krewat
2019-10-25 21:50 ` reed
2019-10-25 22:54 ` Warner Losh [this message]
2019-10-24 2:29 ` Christopher Browne
2019-10-24 8:25 ` Thomas Paulsen
2019-10-21 16:54 ` Angelo Papenhoff
2019-10-23 5:48 ` Lars Brinkhoff
2019-10-21 11:58 Noel Chiappa
2019-10-21 15:44 ` Abhinav Rajagopalan
2019-10-22 2:09 ` Jaap Akkerhuis
2019-10-23 2:00 ` Christopher Browne
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