Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #178524

Re: Some help with dd backing up into an iso

From <tomas@tuxteam.de>
Newsgroups linux.debian.user
Subject Re: Some help with dd backing up into an iso
Date 2017-03-07 09:40 +0100
Message-ID <tiiOZ-4RB-1@gated-at.bofh.it> (permalink)
References <tib17-7Ap-13@gated-at.bofh.it> <tifxL-2pD-1@gated-at.bofh.it> <tiiFk-4KU-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, Mar 07, 2017 at 10:26:25AM +0200, Teemu Likonen wrote:
> David Christensen [2017-03-06 21:05:31-08] wrote:
> 
> >     # dd if=/dev/sda | gzip > myimage.img
> 
> What's the point of using dd?
> 
>     gzip </dev/sda >myimage.img
> 
> I don't know about you but many people seem to think that dd is some
> kind of special tool [...]

> To copy a device file:
> 
>     cat /dev/foo >image.img
> 
> To write to a device:
> 
>     cp image.img /dev/foo
>     sync

Yep. That's when you want to copy all the source, whereas dd comes in
handy whin you know how much to copy. So this idiom makes sense

  dd if=/dev/zero of=lotsofnull bs=1024 count=1024 # copy 1M of zeros

whereas (kids, *don't try this at home)

  cp /dev/zero of=lotsofnull # try to fill up your hard disk

ain't what you're usually looking for ;-P

But yes dd is a dinosaur from olden times where block sizes were a
thing (although I have seen slight speed differences by varying bs
on a fairly modern system, but that might have been some voodoo).

regards
- -- tomás
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iEYEARECAAYFAli+cLoACgkQBcgs9XrR2kZkTwCeI39NI4d06CtufHonaI2u4Ekd
XDEAn2QKG+3SAspnF92iNbMpUNwFifUJ
=elCY
-----END PGP SIGNATURE-----

Back to linux.debian.user | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-07 01:20 +0100
  Re: Some help with dd backing up into an iso Michael Lange <klappnase@freenet.de> - 2017-03-07 02:10 +0100
  Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-07 06:10 +0100
    Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-07 07:00 +0100
      Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 09:00 +0100
        Re: Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-07 18:30 +0100
          Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 20:20 +0100
            Re: Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-08 05:00 +0100
              Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-08 07:00 +0100
              Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-08 12:10 +0100
                MBR partitioning, and content after partition table but before first  partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-09 06:50 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Felix Miata <mrmazda@earthlink.net> - 2017-03-09 08:00 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-10 06:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-10 10:00 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-11 07:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-13 10:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-14 04:40 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David <bouncingcats@gmail.com> - 2017-03-14 11:40 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-15 03:50 +0100
                Re: MBR partitioning, and content after partition table but before  first partition The Wanderer <wanderer@fastmail.fm> - 2017-03-14 13:00 +0100
                Re: MBR partitioning, and content after partition table but before  first partition David Christensen <dpchrist@holgerdanske.com> - 2017-03-15 04:10 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Andy Smith <andy@strugglers.net> - 2017-03-15 04:40 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-15 13:00 +0100
                Re: MBR partitioning, and content after partition table but before first partition "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-09 08:30 +0100
                Re: MBR partitioning, and content after partition table but before  first partition Jonathan Dowland <jmtd@debian.org> - 2017-03-09 15:40 +0100
    Re: Some help with dd backing up into an iso Teemu Likonen <tlikonen@iki.fi> - 2017-03-07 09:30 +0100
      Re: Some help with dd backing up into an iso <tomas@tuxteam.de> - 2017-03-07 09:40 +0100
        Re: Some help with dd backing up into an iso Teemu Likonen <tlikonen@iki.fi> - 2017-03-07 10:00 +0100
          Re: Some help with dd backing up into an iso <tomas@tuxteam.de> - 2017-03-07 10:10 +0100
          Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 16:20 +0100
      Re: Some help with dd backing up into an iso Jonathan Dowland <jmtd@debian.org> - 2017-03-07 11:10 +0100
      Re: Some help with dd backing up into an iso David Christensen <dpchrist@holgerdanske.com> - 2017-03-08 06:00 +0100
  Re: Some help with dd backing up into an iso Mark Fletcher <mark27q1@gmail.com> - 2017-03-07 12:10 +0100
  Re: Some help with dd backing up into an iso Eduardo M KALINOWSKI <eduardo@kalinowski.com.br> - 2017-03-07 14:50 +0100
  Re: Some help with dd backing up into an iso Elimar Riesebieter <riesebie@lxtec.de> - 2017-03-07 15:20 +0100
  Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 16:20 +0100
    Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 18:10 +0100
      Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 19:00 +0100
        Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 20:30 +0100
          Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-07 21:30 +0100
            Re: Some help with dd backing up into an iso "Thomas Schmitt" <scdbackup@gmx.net> - 2017-03-07 22:10 +0100
              Re: Some help with dd backing up into an iso GiaThnYgeia <GiaThnYgeia@openmailbox.org> - 2017-03-08 18:30 +0100
                Re: Some help with dd backing up into an iso David Wright <deblis@lionunicorn.co.uk> - 2017-03-08 19:20 +0100

csiph-web