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Re: dd - proper use or more suitable program

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  Re: dd - proper use or more suitable program Andy Smith <andy@strugglers.net> - 2016-11-11 18:00 +0100
    Re: dd - proper use or more suitable program Christian Seiler <christian@iwakd.de> - 2016-11-11 18:40 +0100
      Re: dd - proper use or more suitable program The Wanderer <wanderer@fastmail.fm> - 2016-11-11 19:20 +0100
        Re: dd - proper use or more suitable program Richard Owlett <rowlett@cloud85.net> - 2016-11-11 22:40 +0100
          Re: dd - proper use or more suitable program Andy Smith <andy@strugglers.net> - 2016-11-12 05:50 +0100
            Re: dd - proper use or more suitable program Richard Owlett <rowlett@cloud85.net> - 2016-11-12 09:20 +0100
    Re: dd - proper use or more suitable program Nicolas George <george@nsup.org> - 2016-11-11 19:00 +0100
      Re: dd - proper use or more suitable program Richard Owlett <rowlett@cloud85.net> - 2016-11-11 22:40 +0100
        Re: dd - proper use or more suitable program Christian Seiler <christian@iwakd.de> - 2016-11-12 08:40 +0100
          Re: dd - proper use or more suitable program Richard Owlett <rowlett@cloud85.net> - 2016-11-12 09:30 +0100
            Re: dd - proper use or more suitable program Richard Owlett <rowlett@cloud85.net> - 2016-11-12 18:30 +0100
              Re: dd - proper use or more suitable program Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-11-12 19:30 +0100
                Re: dd - proper use or more suitable program Richard Owlett <rowlett@cloud85.net> - 2016-11-12 20:30 +0100
                  Re: dd - proper use or more suitable program Ben Caradoc-Davies <ben@transient.nz> - 2016-11-12 21:00 +0100
                    Re: dd - proper use or more suitable program Brian <ad44@cityscape.co.uk> - 2016-11-12 21:10 +0100
                  Re: dd - proper use or more suitable program <tomas@tuxteam.de> - 2016-11-12 22:00 +0100
                    Invoking ddrescue Richard Owlett <rowlett@cloud85.net> - 2016-11-13 04:10 +0100
                      Re: Invoking ddrescue "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-13 13:00 +0100
                        Re: Invoking ddrescue <tomas@tuxteam.de> - 2016-11-13 13:10 +0100
                      Re: Invoking ddrescue <tomas@tuxteam.de> - 2016-11-13 13:00 +0100
                      Re: Invoking ddrescue "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-13 13:40 +0100
                        Re: Invoking ddrescue Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-11-13 13:50 +0100
                          Re: Invoking ddrescue Nicolas George <george@nsup.org> - 2016-11-13 14:00 +0100
                          Re: Invoking ddrescue "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-13 14:40 +0100
                            Re: Invoking ddrescue Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-11-13 15:10 +0100
                              Re: Invoking ddrescue "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-13 16:10 +0100
                                Re: Invoking ddrescue Richard Owlett <rowlett@cloud85.net> - 2016-11-13 17:30 +0100
                      Re: Invoking ddrescue Brian <ad44@cityscape.co.uk> - 2016-11-13 15:20 +0100
                      Progress report Re: Invoking ddrescue Richard Owlett <rowlett@cloud85.net> - 2016-11-14 20:20 +0100
                        Re: Progress report Re: Invoking ddrescue Jonathan Dowland <jmtd@debian.org> - 2016-11-14 21:20 +0100
                          Re: Progress report Re: Invoking ddrescue Richard Owlett <rowlett@cloud85.net> - 2016-11-14 22:00 +0100
                        Re: Progress report Re: Invoking ddrescue <tomas@tuxteam.de> - 2016-11-14 21:30 +0100
                          Re: Progress report Re: Invoking ddrescue Richard Owlett <rowlett@cloud85.net> - 2016-11-14 22:20 +0100
                        Re: Progress report Re: Invoking ddrescue "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-14 21:30 +0100
                          Re: Progress report Re: Invoking ddrescue Richard Owlett <rowlett@cloud85.net> - 2016-11-14 22:10 +0100
                          Re: Progress report Re: Invoking ddrescue Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-11-17 20:20 +0100
                        SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Richard Owlett <rowlett@cloud85.net> - 2016-11-14 23:40 +0100
                          Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Brian <ad44@cityscape.co.uk> - 2016-11-15 00:30 +0100
                            Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Richard Owlett <rowlett@cloud85.net> - 2016-11-15 04:00 +0100
                              Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Brian <ad44@cityscape.co.uk> - 2016-11-15 21:00 +0100
                                Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] <tomas@tuxteam.de> - 2016-11-15 22:00 +0100
                          Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-15 12:50 +0100
                            Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Brian <ad44@cityscape.co.uk> - 2016-11-15 13:30 +0100
                              Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-15 13:50 +0100
                            Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Richard Owlett <rowlett@cloud85.net> - 2016-11-15 13:50 +0100
                            Re: SUC[C]ESS!!! - was [Re: Progress report Re: Invoking ddrescue] David Wright <deblis@lionunicorn.co.uk> - 2016-11-15 16:30 +0100
                              Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] "Thomas Schmitt" <scdbackup@gmx.net> - 2016-11-15 17:20 +0100
                                Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue] Greg Wooledge <wooledg@eeg.ccf.org> - 2016-11-15 17:30 +0100

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#174641 — Re: Invoking ddrescue

Hi,

Richard Owlett wrote:
> > > How do I prepare to invoke

i wrote:
> > ddrescue -p /dev/sdc1 /mnt/my_sdb6/my_sdc1 /mnt/my_sdb6/sdc1_log

tomas wrote:
> his "big" disk
> (where the backup is going to) has already a file system and is mounted.

Meanwhile i began to doubt this. (Why would Richard need 5 lines ?)
So i tried to find a Debian tutorial for creating a new filesystem on
a previously unused partition. No luck.

So - for the records and for checking by others - old school would be to
do as superuser:
-----------------------------------------------------------------------

Check whether there is really no filesystem on /dev/sdb6 !

Only if not, create one by

  mkfs -t ext3 /dev/sdb6

Prepare the mount point

  mkdir /mnt/my_sdb6

Make it permanent by

  vi /etc/fstab

where you add this line

  /dev/sdb6       /mnt/my_sdb6    ext3    rw  0       0

Mount it for the first time

  mount /mnt/my_sdb6

End being superuser.

-----------------------------------------------------------------------

A german server provider proposes similar (omit the cfdisk run, because
your partition already exists):
  https://www.thomas-krenn.com/en/wiki/Hard_Disk_Formatting/Partitioning_and_Mounting_in_Debian_Linux


Have a nice day :)

Thomas

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#174643 — Re: Invoking ddrescue

Le 13/11/2016 à 13:29, Thomas Schmitt a écrit :
>
> Check whether there is really no filesystem on /dev/sdb6 !

How ? I may suggest amongst others :
file -sk /dev/sdb6
wipefs /dev/sdb6
blkid /dev/sdb6

> Only if not, create one by
>
>   mkfs -t ext3 /dev/sdb6

Why use an obsolete filesystem type as ext3 instead of ext4 ?

> Prepare the mount point
>
>   mkdir /mnt/my_sdb6
>
> Make it permanent by
>
>   vi /etc/fstab
>
> where you add this line
>
>   /dev/sdb6       /mnt/my_sdb6    ext3    rw  0       0

My understanding of the FHS was that /mnt was intended to be used as a 
temporary mount point, not to contain any subdirectories used as 
permanent mount points.

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#174644 — Re: Invoking ddrescue

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Le tridi 23 brumaire, an CCXXV, Pascal Hambourg a écrit :
> >Check whether there is really no filesystem on /dev/sdb6 !
> How ?

Try to mount it? It could be dangerous in theory if the device came from
a malicious source, but not in this instance.

> My understanding of the FHS was that /mnt was intended to be used as a
> temporary mount point, not to contain any subdirectories used as permanent
> mount points.

The FHS is not mandatory, any sysadmin is free to ignore any of its
points when they think it makes no sense.

I have been using /mnt like that for a long time and not had any trouble
with it.

Regards,

-- 
  Nicolas George

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#174649 — Re: Invoking ddrescue

Hi,

i wrote:
> > Check whether there is really no filesystem on /dev/sdb6 !

Pascal Hambourg wrote:
> How ? I may suggest amongst others :

  file -sk /dev/sdb6

Good proposal. Richard: Add this to mine.

An empty partition should report

  /dev/sdb6: data

whereas a recognizable filesystem should tell lots of info, like

  /dev/sdb6:  Linux rev 1.0 ext4 filesystem data, ...
or
  /dev/sdb6: DOS/MBR boot sector, ... FAT ...

A Linux swap partition looks like

  /dev/sdb6: Linux/i386 swap file ...


-------------------------------------------------------------------
Questions of long term style rather than immediate functionality of
the proposal:

> Why use an obsolete filesystem type as ext3 instead of ext4 ?

As said: Old school.
Just some filesystem type that is supposed to take large data files.


> My understanding of the FHS was that /mnt was intended to be used as a
> temporary mount point, not to contain any subdirectories used as permanent
> mount points.

Using /mnt for custom mount points does not look like a grave mistake,
at least.

Old school is:
  http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/mnt.html

  "This is a generic mount point under which you mount your filesystems
   or devices. [...] This directory usually contains mount points or
   sub-directories where you mount your floppy and your CD. You can also
   create additional mount-points here if you wish."

About as old as above LFS is:
  http://www.pathname.com/fhs/pub/fhs-2.3.html#MNTMOUNTPOINTFORATEMPORARILYMOUNT

  "/mnt : Mount point for a temporarily mounted filesystem
   Purpose
   This directory is provided so that the system administrator may
   temporarily mount a filesystem as needed. The content of this directory
   is a local issue and should not affect the manner in which any program
   is run.
   This directory must not be used by installation programs: a suitable
   temporary directory not in use by the system must be used instead."

Do we have newer specs ?


Have a nice day :)

Thomas

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#174653 — Re: Invoking ddrescue

Le 13/11/2016 à 14:35, Thomas Schmitt a écrit :
>
> Old school is:
>   http://www.tldp.org/LDP/Linux-Filesystem-Hierarchy/html/mnt.html
>
>   "This is a generic mount point under which you mount your filesystems
>    or devices. [...] This directory usually contains mount points or
>    sub-directories where you mount your floppy and your CD. You can also
>    create additional mount-points here if you wish."

Sounds contradictory. How can it be a mount point and contain mount 
points or sub-directories at the same time ? If you mount something on 
it, the sub-directories are masked.

> About as old as above LFS is:
>   http://www.pathname.com/fhs/pub/fhs-2.3.html#MNTMOUNTPOINTFORATEMPORARILYMOUNT
>
>   "/mnt : Mount point for a temporarily mounted filesystem

Sounds clear : *a* *temporarily* mounted filesystem.

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#174656 — Re: Invoking ddrescue

Hi,

Richard:
You may as well use /media instead of /mnt.
I think it makes no decisive difference for your purpose.

The following discussion wanders away from the request for help
into the field of best practices with system administration:

I quoted:
> >   http://www.pathname.com/fhs/pub/fhs-2.3.html#MNTMOUNTPOINTFORATEMPORARILYMOUNT
> > "/mnt : Mount point for a temporarily mounted filesystem

Pascal Hambourg wrote:
> Sounds clear : *a* *temporarily* mounted filesystem.

Clear only until you read on further
  "This directory is provided so that the system administrator may
   temporarily mount a filesystem as needed. The content of this directory
   is a local issue and should not affect the manner in which any program
   is run."

What if the admin needs to temporarily mount two filesystems ?
Why should the _directory_ and not the _mounted filesystem_ contain
something ?

I read two conflicting models from both specs. LFH leans to /mnt/*,
whereas FHS leans to /mnt.
Obviously a clear word was not intended back in 2004.
(I drag with me a /mnt directory with entrails since last century. So i
 cannot even tell what Debian installs.)

On my own systems i use the /mnt/* model, because it does not interfere
with /media, where the automats are working.


Have a nice day :)

Thomas

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#174658 — Re: Invoking ddrescue

On 11/13/2016 9:01 AM, Thomas Schmitt wrote:
> Hi,
>
> Richard:
> You may as well use /media instead of /mnt.
> I think it makes no decisive difference for your purpose.

I'll use /mnt as it is empty and I will thus be able to 
distinguish between what Debian does and what I'm responsible for.

Now to reread posts and jot coherent notes.
Thank you.

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#174654 — Re: Invoking ddrescue

On Sat 12 Nov 2016 at 21:05:17 -0600, Richard Owlett wrote:

> On my left hand I have a defective hard disk - AKA /dev/sdc .
> On my right hand I have a partitioned device waiting for data - AKA
> /dev/sdb6 .

[...Snip...]

> How do I prepare to invoke
>    ddrescue /dev/sdc /mnt/repaired.img /mnt/repaired.log

1. This partition, /dev/sda6; is it formatted? If not. do

	mkfs.ext4 /dev/sda6

   The partition is now capable of holding files.

2. Mount the partition: mount /dev/sda6 /mnt

   The partition is now capable of receiving files.

3. Attach the defective hard disk to the machine which has the mounted
   partition after doing 'lsblk'. Do 'lsblk' again. Identify the name
   of the attached device, /dev/sdx. x=a, b, c etc.

4. Now: ddrescue /dev/sdx /mnt/repaired.img /mnt/repaired.log

-- 
Brian.

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#174710 — Progress report Re: Invoking ddrescue

There is light at the end of the tunnel which doesn't appear to 
be an oncoming train ;/

This is a manually created transcript of what I've done this morning.
I physically can *NOT* do a copy-n-paste of what's happening as it is
currently in progress on a separate _intentionally isolated_ laptop.

My procedure has been to login "root" at the Jessie boot screen.
I did *NOT* login as "richard" followed by executing "su" in a 
terminal.
There *appears* to be subtle differences -- more investigation 
needed.

A. Examine state of state of proposed target {/dev/sdb6} and the 
defective
    drive {dev/sdc} using Gparted
      I deleted existing but empty /dev/sdb6, created a new one 
with an ext4
      file system labeled "recovered".
      The damaged drive shows as /dev/sdc partitioned as
          /dev/sdc1 ntfs  primary -- warning triangle and "---" 
for used/unused space
          /dev/sdc2 fat32 primary -- displays reasonable values 
for used/unused
          /dev/sdc3 extended
          /dev/sdc5 ntfs  logical -- displays reasonable values 
for used/unused
          /dev/sdc6 ntfs  logical -- displays reasonable values 
for used/unused
          /dev/sdc7 ntfs  logical -- displays reasonable values 
for used/unused
B. Prepare the mount point
      mkdir /mnt/my_sdb6
C. Make it permanent by editing /etc/fstab by adding this line
      /dev/sdb6       /mnt/my_sdb6    ext4    rw  0       0
D. Mount it for the first time
      mount /mnt/my_sdb6
E. Attempt rescue with
    ddrescue -p /dev/sdc1 /mnt/my_sdb6/my_sdc1 /mnt/my_sdb6/sdc1_log

The rescue appears to be progressing. ddrescue has been running 
for 1/2 and reports rescuing ~47GB without any _reported_ errors. 
That's unexpected as the partition was the Windows C: drive and 
WinXP refused to boot. At the current rate I've another 2 hrs 
minimum. I'm not concerned about the speed as both hard drive are 
on USB2 ports.

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#174712 — Re: Progress report Re: Invoking ddrescue

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On Mon, Nov 14, 2016 at 01:09:51PM -0600, Richard Owlett wrote:
> There is light at the end of the tunnel which doesn't appear to be an
> oncoming train ;/
> 
> This is a manually created transcript of what I've done this morning.
> I physically can *NOT* do a copy-n-paste of what's happening as it is
> currently in progress on a separate _intentionally isolated_ laptop.

Broadly the transcript looks fine to me.

> The rescue appears to be progressing. ddrescue has been running for 1/2 and
> reports rescuing ~47GB without any _reported_ errors. That's unexpected as
> the partition was the Windows C: drive and WinXP refused to boot.

It's possible that WinXP has corrupted files, or a corrupted filesystem, on top
of a perfectly fine drive. This can happen for any number of reasons, including
unexpected power cuts whilst Win XP was applying an update of some sort and in
the middle of writing a critical file.

Whilst ddrescue is running, you could, if you wish, check the drive's S.M.A.R.T.
(Self-Monitoring, Analysis and Reporting Technology) logs, if you have smartctl
(from the smartmontools package) installed. The command (as root/superuser) is

	smartctl -a /dev/sdc

This *should* not have any impact whatsoever on the running ddrescue. The output
is quite long so you may wish to pipe the above command to a pager (such as less)
by appending "| less", and/or capture the output to another file (achieved at the
same time by piping to 'tee' first, e.g. | tee -a some-output-file | less)

The output might include lines such as the following  (all taken from running the
command on one of my HDDs):

...
> === START OF READ SMART DATA SECTION ===
> SMART overall-health self-assessment test result: PASSED
...
> SMART Error Log Version: 1
> No Errors Logged
...

The output (in particular the "Vendor Specific SMART Attributes with Thresholds")
can be hard to interpret, which is why I suggested also saving to a file, but
would tell you if the drive itself thinks it has suffered a failure.

However if you are very risk-averse you are probably best leaving the machine
entirely until ddrescue is complete.

(definitely for another time: you can also instruct drives which support S.M.A.R.T.
to perform one of a number of self-tests for problems using smartctl)

> At the current rate I've another 2 hrs minimum. I'm not concerned about the
> speed as both hard drive are on USB2 ports.

It can take a very long time, especially once it gets to the later stages
(scraping, trims, retries, etc.)

I've been reading a single damaged DVD-r (capacity ~4GiB) for over a week and
I'm not finished (I have interrupted the process however, as I am about to a 
different optical drive, which can be helpful when recovering from optical media
but this is not relevant to HDDs or your situation)

-- 
Jonathan Dowland
Please do not CC me, I am subscribed to the list.

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#174715 — Re: Progress report Re: Invoking ddrescue

On 11/14/2016 2:16 PM, Jonathan Dowland wrote:
> On Mon, Nov 14, 2016 at 01:09:51PM -0600, Richard Owlett wrote:
>> There is light at the end of the tunnel which doesn't appear to be an
>> oncoming train ;/
>>
>> This is a manually created transcript of what I've done this morning.
>> I physically can *NOT* do a copy-n-paste of what's happening as it is
>> currently in progress on a separate _intentionally isolated_ laptop.
>
> Broadly the transcript looks fine to me.
>
>> The rescue appears to be progressing. ddrescue has been running for 1/2 and
>> reports rescuing ~47GB without any _reported_ errors. That's unexpected as
>> the partition was the Windows C: drive and WinXP refused to boot.
>
> It's possible that WinXP has corrupted files, or a corrupted filesystem, on top
> of a perfectly fine drive. This can happen for any number of reasons, including
> unexpected power cuts whilst Win XP was applying an update of some sort and in
> the middle of writing a critical file.
>
> Whilst ddrescue is running, you could, if you wish, check the drive's S.M.A.R.T.
> (Self-Monitoring, Analysis and Reporting Technology) logs, if you have smartctl
> (from the smartmontools package) installed. The command (as root/superuser) is
>
> 	smartctl -a /dev/sdc
>
> This *should* not have any impact whatsoever on the running ddrescue. The output
> is quite long so you may wish to pipe the above command to a pager (such as less)
> by appending "| less", and/or capture the output to another file (achieved at the
> same time by piping to 'tee' first, e.g. | tee -a some-output-file | less)
>
> The output might include lines such as the following  (all taken from running the
> command on one of my HDDs):
>
> ...
>> === START OF READ SMART DATA SECTION ===
>> SMART overall-health self-assessment test result: PASSED
> ...
>> SMART Error Log Version: 1
>> No Errors Logged
> ...
>
> The output (in particular the "Vendor Specific SMART Attributes with Thresholds")
> can be hard to interpret, which is why I suggested also saving to a file, but
> would tell you if the drive itself thinks it has suffered a failure.
>
> However if you are very risk-averse you are probably best leaving the machine
> entirely until ddrescue is complete.
>
> (definitely for another time: you can also instruct drives which support S.M.A.R.T.
> to perform one of a number of self-tests for problems using smartctl)
>
>> At the current rate I've another 2 hrs minimum. I'm not concerned about the
>> speed as both hard drive are on USB2 ports.
>
> It can take a very long time, especially once it gets to the later stages
> (scraping, trims, retries, etc.)
>
> I've been reading a single damaged DVD-r (capacity ~4GiB) for over a week and
> I'm not finished (I have interrupted the process however, as I am about to a
> different optical drive, which can be helpful when recovering from optical media
> but this is not relevant to HDDs or your situation)
>

I think I may go with the idea of corrupted file contents which 
create meaningless content that can be reliably read. I still 
have no _reported_ errors although the "current rate:" 
occasionally drops to ~3% of "average rate:". I don't know how 
hard WinXP tries to read marginal sectors.

In this case, I am significantly "very risk-averse" ;/ It is 
running. I will leave well enough alone.

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#174713 — Re: Progress report Re: Invoking ddrescue

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

On Mon, Nov 14, 2016 at 01:09:51PM -0600, Richard Owlett wrote:
> There is light at the end of the tunnel which doesn't appear to be
> an oncoming train ;/
> 
> This is a manually created transcript of what I've done this morning.
> I physically can *NOT* do a copy-n-paste of what's happening as it is
> currently in progress on a separate _intentionally isolated_ laptop.
> 
> My procedure has been to login "root" at the Jessie boot screen.
> I did *NOT* login as "richard" followed by executing "su" in a
> terminal.
> There *appears* to be subtle differences -- more investigation
> needed.

There is. If you invoke just "su", you inherit (more or less) the
(regular) user's environment, with some exceptions. If you invoke
"su -" (or equivalently "su -l") you get a fresh environment for
root, as if you had logged in as root directly.

The gory details are in su's man page (a bit complicated by the
fact that su can do more things, e.g. su'ing to another user instead
of root, executing just one command as the new user, and so on).

Jonathan commented on the other points much better than I could,
so I'll stop here :-)

regards
- -- tomás
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#174717 — Re: Progress report Re: Invoking ddrescue

On 11/14/2016 2:27 PM, tomas@tuxteam.de wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Mon, Nov 14, 2016 at 01:09:51PM -0600, Richard Owlett wrote:
>> There is light at the end of the tunnel which doesn't appear to be
>> an oncoming train ;/
>>
>> This is a manually created transcript of what I've done this morning.
>> I physically can *NOT* do a copy-n-paste of what's happening as it is
>> currently in progress on a separate _intentionally isolated_ laptop.
>>
>> My procedure has been to login "root" at the Jessie boot screen.
>> I did *NOT* login as "richard" followed by executing "su" in a
>> terminal.
>> There *appears* to be subtle differences -- more investigation
>> needed.
>
> There is. If you invoke just "su", you inherit (more or less) the
> (regular) user's environment, with some exceptions. If you invoke
> "su -" (or equivalently "su -l") you get a fresh environment for
> root, as if you had logged in as root directly.

My observed symptoms would seem to match.
I have a test case in mind that could verify that.
It will have to wait. I have a higher priority project thirsting 
for an available 300GB drive. It is the motivation for a lot of 
my recent posts ;/

>
> The gory details are in su's man page (a bit complicated by the
> fact that su can do more things, e.g. su'ing to another user instead
> of root, executing just one command as the new user, and so on).
>
> Jonathan commented on the other points much better than I could,
> so I'll stop here :-)
>
> regards
> - -- tomás

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#174714 — Re: Progress report Re: Invoking ddrescue

Hi,

Richard Owlett wrote:
>          /dev/sdc3 extended

This one does not need to be copied because it is a container around
the "logical" partitions sd5, sdc6, sdc7.


> ddrescue has been running for 1/2 and
> reports rescuing ~47GB without any _reported_ errors. That's unexpected as
> the partition was the Windows C: drive and WinXP refused to boot.

Do you get any specific messages from the boot refusal ?
Like bad disk or so ?

If the computer has EFI boot firmware, if it is in non-legacy mode, and if
dev/sdc2 is reported by e.g. /sbin/fdisk -l as type "EFI (FAT-12/16/32)",
then booting starts there.

If the computer has old BIOS or EFI in legacy mode, then booting starts
at block 0 of the base device /dev/sdc. Normally the first partition starts
not there but rather 31 to 2048 blocks later.


Have a nice day :)

Thomas

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#174716 — Re: Progress report Re: Invoking ddrescue

On 11/14/2016 2:23 PM, Thomas Schmitt wrote:
> Hi,
>
> Richard Owlett wrote:
>>           /dev/sdc3 extended
>
> This one does not need to be copied because it is a container around
> the "logical" partitions sd5, sdc6, sdc7.
>

<Chuckle><Chuckle><GRIN>
Back in the day I was involved in QA/QC and bailing out our field 
service people


>
>> ddrescue has been running for 1/2 and
>> reports rescuing ~47GB without any _reported_ errors. That's unexpected as
>> the partition was the Windows C: drive and WinXP refused to boot.
>
> Do you get any specific messages from the boot refusal ?
> Like bad disk or so ?

No way to know at this late date. I has not been in a computer 
for over a year, possibly 2.

Trouble shooting the drive has been on my "to do" list. Right now 
I could use another 300GB of free (as in beer) storage. I have no 
need of another Windows machine.

>
> If the computer has EFI boot firmware, if it is in non-legacy mode, and if
> dev/sdc2 is reported by e.g. /sbin/fdisk -l as type "EFI (FAT-12/16/32)",
> then booting starts there.
>
> If the computer has old BIOS or EFI in legacy mode, then booting starts
> at block 0 of the base device /dev/sdc. Normally the first partition starts
> not there but rather 31 to 2048 blocks later.
>
>
> Have a nice day :)
>
> Thomas
>
>

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#174829 — Re: Progress report Re: Invoking ddrescue

Le 14/11/2016 à 21:23, Thomas Schmitt a écrit :
>
> If the computer has EFI boot firmware, if it is in non-legacy mode

Windows XP x86/x64 cannot boot in UEFI mode.
Any Windows version won't boot in UEFI mode from a disk with a DOS/MBR 
partition table.

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#174722 — SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue]

ddrescue has run to completion without _reported_ errors for all 
partitions of the drive. I understand that does *NOT* guarantee 
that the files are not corrupt.

I've read the man page of su with recent experiences in mind.
I agree with tomas that some of my recent problems relate to the 
differences between "su" and "su --login".



On 11/14/2016 1:09 PM, Richard Owlett wrote:
> There is light at the end of the tunnel which doesn't appear to
> be an oncoming train ;/
>
> This is a manually created transcript of what I've done this
> morning.
> I physically can *NOT* do a copy-n-paste of what's happening as
> it is
> currently in progress on a separate _intentionally isolated_ laptop.
>
> My procedure has been to login "root" at the Jessie boot screen.
> I did *NOT* login as "richard" followed by executing "su" in a
> terminal.
> There *appears* to be subtle differences -- more investigation
> needed.
>
> A. Examine state of state of proposed target {/dev/sdb6} and the
> defective
>     drive {dev/sdc} using Gparted
>       I deleted existing but empty /dev/sdb6, created a new one
> with an ext4
>       file system labeled "recovered".
>       The damaged drive shows as /dev/sdc partitioned as
>           /dev/sdc1 ntfs  primary -- warning triangle and "---"
> for used/unused space
>           /dev/sdc2 fat32 primary -- displays reasonable values
> for used/unused
>           /dev/sdc3 extended
>           /dev/sdc5 ntfs  logical -- displays reasonable values
> for used/unused
>           /dev/sdc6 ntfs  logical -- displays reasonable values
> for used/unused
>           /dev/sdc7 ntfs  logical -- displays reasonable values
> for used/unused
> B. Prepare the mount point
>       mkdir /mnt/my_sdb6
> C. Make it permanent by editing /etc/fstab by adding this line
>       /dev/sdb6       /mnt/my_sdb6    ext4    rw  0       0
> D. Mount it for the first time
>       mount /mnt/my_sdb6
> E. Attempt rescue with
>     ddrescue -p /dev/sdc1 /mnt/my_sdb6/my_sdc1 /mnt/my_sdb6/sdc1_log
>
> The rescue appears to be progressing. ddrescue has been running
> for 1/2 and reports rescuing ~47GB without any _reported_ errors.
> That's unexpected as the partition was the Windows C: drive and
> WinXP refused to boot. At the current rate I've another 2 hrs
> minimum. I'm not concerned about the speed as both hard drive are
> on USB2 ports.
>
>
>

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#174725 — Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue]

On Mon 14 Nov 2016 at 16:29:52 -0600, Richard Owlett wrote:

> ddrescue has run to completion without _reported_ errors for all partitions
> of the drive. I understand that does *NOT* guarantee that the files are not
> corrupt.
> 
> I've read the man page of su with recent experiences in mind.
> I agree with tomas that some of my recent problems relate to the differences
> between "su" and "su --login".

tomas did not say he agreed that any of your recent problems relate
to the differences between "su" and "su --login". He explained the
difference between "su" and "su -", a factual matter.

Speaking of facts: we've had the appearance of subtle differences and
matching observed symptoms. Fuzzy. Nothing concrete and nothing that
doesn't involve speculation or possibly misobservation. As far as I am
concerned, all the commands used to carry out your task can be issued
successfully as root or after a su to root.

-- 
Brian.

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#174727 — Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue]

On 11/14/2016 5:20 PM, Brian wrote:
> On Mon 14 Nov 2016 at 16:29:52 -0600, Richard Owlett wrote:
>
>> ddrescue has run to completion without _reported_ errors for all partitions
>> of the drive. I understand that does *NOT* guarantee that the files are not
>> corrupt.
>>
>> I've read the man page of su with recent experiences in mind.
>> I agree with tomas that some of my recent problems relate to the differences
>> between "su" and "su --login".
>
> tomas did not say he agreed that any of your recent problems relate
> to the differences between "su" and "su --login". He explained the
> difference between "su" and "su -", a factual matter.
>
> Speaking of facts: we've had the appearance of subtle differences and
> matching observed symptoms. Fuzzy. Nothing concrete and nothing that
> doesn't involve speculation or possibly misobservation. As far as I am
> concerned, all the commands used to carry out your task can be issued
> successfully as root or after a su to root.
>

gee whiz what insight
writen by some one who actually read my reply to 
tomas?????????????????????

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#174773 — Re: SUCESS!!! - was [Re: Progress report Re: Invoking ddrescue]

On Mon 14 Nov 2016 at 20:49:48 -0600, Richard Owlett wrote:

> On 11/14/2016 5:20 PM, Brian wrote:
> >On Mon 14 Nov 2016 at 16:29:52 -0600, Richard Owlett wrote:
> >
> >>ddrescue has run to completion without _reported_ errors for all partitions
> >>of the drive. I understand that does *NOT* guarantee that the files are not
> >>corrupt.
> >>
> >>I've read the man page of su with recent experiences in mind.
> >>I agree with tomas that some of my recent problems relate to the differences
> >>between "su" and "su --login".
> >
> >tomas did not say he agreed that any of your recent problems relate
> >to the differences between "su" and "su --login". He explained the
> >difference between "su" and "su -", a factual matter.
> >
> >Speaking of facts: we've had the appearance of subtle differences and
> >matching observed symptoms. Fuzzy. Nothing concrete and nothing that
> >doesn't involve speculation or possibly misobservation. As far as I am
> >concerned, all the commands used to carry out your task can be issued
> >successfully as root or after a su to root.
> >
> 
> gee whiz what insight

It's what you are paying for. Enjoy.

> writen by some one who actually read my reply to tomas?????????????????????

Reading and understanding. From this thread you will appreciate the
difference,

-- 
Brian.

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