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evoweiss Veteran
Joined: 07 Sep 2003 Posts: 1678 Location: Edinburgh, UK
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Posted: Tue Jul 15, 2014 11:37 pm Post subject: |
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NeddySeagoon wrote: | USB HDD are slow, USB2 does not support DMA so the CPU has to read and write every byte.
USB to USB is even slower. USB3 is supposed to be better - it does DMA. |
I'll say, though the wait is finally over.
Quote: | Show me some of the commands you hove been using and the resulting error messages in dmesg. |
Here's a sampling. I went through the entire list you provided.
Code: | # mount -o ro,offset=32256,sb=102400000 /dev/sdd1 /mnt/image/
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
# mount -o ro,offset=1048576,sb=102400000 /dev/sdd1 /mnt/image/
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
# mount -o ro,offset=32256,sb=214990848 /dev/sdd1 /mnt/image/
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so.
# mount -o ro,offset=32256,sb=214990848 /dev/sdd1 /mnt/image/
mount: wrong fs type, bad option, bad superblock on /dev/loop0,
missing codepage or helper program, or other error
In some cases useful info is found in syslog - try
dmesg | tail or so. |
The dmesg output is
Code: |
[952689.695228] UDF-fs: bad mount option "sb=102400000" or missing value
[952710.991317] EXT3-fs (loop0): error: unable to read superblock
[952710.991395] EXT2-fs (loop0): error: unable to read superblock
[952710.991464] EXT4-fs (loop0): unable to read superblock
[952710.991734] UDF-fs: bad mount option "sb=102400000" or missing value
[952728.361532] EXT3-fs (loop0): error: unable to read superblock
[952728.361630] EXT2-fs (loop0): error: unable to read superblock
[952728.361697] EXT4-fs (loop0): unable to read superblock
[952728.361962] UDF-fs: bad mount option "sb=214990848" or missing value
[952740.133372] EXT3-fs (loop0): error: unable to read superblock
[952740.133562] EXT2-fs (loop0): error: unable to read superblock
[952740.133704] EXT4-fs (loop0): unable to read superblock
[952740.134160] UDF-fs: bad mount option "sb=214990848" or missing value
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Its possible that the root directory has been trashed. Thats why I was interested in the size of the file you incorrectly dd'ed.[/quote]
Thankfully, prior to crashing and burning I made sure to save the output indicating how much had been overwritten, etc.
Code: |
dd if=/mnt/hdb1/Video/misc/linuxmint-16-xfce-dvd-32bit.iso of=/dev/sdc oflag=direct bs=1048576
dd: error writing ‘/dev/sdc’: Input/output error
26+0 records in
25+0 records out
26214400 bytes (26 MB) copied, 24.7105 s, 1.1 MB/s
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So not very much, really.
Best,
Alex |
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NeddySeagoon Administrator
Joined: 05 Jul 2003 Posts: 54096 Location: 56N 3W
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Posted: Wed Jul 16, 2014 5:27 pm Post subject: |
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evoweiss,
Ahhh. The sb= parameter I provided is in units of of the filesystem (logical) block size. Thats 4k for your filesystem.
However, mount does not know the file system block size until its succeeded. That is too late for you.
Let me remind you man nount: | sb=n Instead of block 1, use block n as superblock. This could be
useful when the filesystem has been damaged. (Earlier, copies
of the superblock would be made every 8192 blocks: in block 1,
8193, 16385, ... (and one got thousands of copies on a big
filesystem). Since version 1.08, mke2fs has a -s (sparse
superblock) option to reduce the number of backup superblocks,
and since version 1.15 this is the default. Note that this may
mean that ext2 filesystems created by a recent mke2fs cannot be
mounted r/w under Linux 2.0.*.) The block number here uses 1 k
units. Thus, if you want to use logical block 32768 on a
filesystem with 4 k blocks, use "sb=131072".
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Notice the factor of 4 in Code: | The block number here uses 1 k
units. Thus, if you want to use logical block 32768 on a
filesystem with 4 k blocks, use "sb=131072". |
Your sb= parameters are out by a factor of 4.
With the first 26Mb gone, there is no point in trying alternate superblocks there. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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evoweiss Veteran
Joined: 07 Sep 2003 Posts: 1678 Location: Edinburgh, UK
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Posted: Wed Jul 16, 2014 7:57 pm Post subject: |
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Dear Neddy,
I take it to mean there's no hope then, right?
Is there any way to possibly rescue files from the drive?
Best,
Alex
NeddySeagoon wrote: | evoweiss,
Ahhh. The sb= parameter I provided is in units of of the filesystem (logical) block size. Thats 4k for your filesystem.
However, mount does not know the file system block size until its succeeded. That is too late for you.
Let me remind you man nount: | sb=n Instead of block 1, use block n as superblock. This could be
useful when the filesystem has been damaged. (Earlier, copies
of the superblock would be made every 8192 blocks: in block 1,
8193, 16385, ... (and one got thousands of copies on a big
filesystem). Since version 1.08, mke2fs has a -s (sparse
superblock) option to reduce the number of backup superblocks,
and since version 1.15 this is the default. Note that this may
mean that ext2 filesystems created by a recent mke2fs cannot be
mounted r/w under Linux 2.0.*.) The block number here uses 1 k
units. Thus, if you want to use logical block 32768 on a
filesystem with 4 k blocks, use "sb=131072".
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Notice the factor of 4 in Code: | The block number here uses 1 k
units. Thus, if you want to use logical block 32768 on a
filesystem with 4 k blocks, use "sb=131072". |
Your sb= parameters are out by a factor of 4.
With the first 26Mb gone, there is no point in trying alternate superblocks there. |
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