Hi,
I'm deleting a harddrive with 4 partitions. I created mapfiles of
partition 3 and 4 with partclone -D respectively and used something like
ddrescue -yD bigfilewithzeros /dev/sdb3 part3.mapfile to overwrite only
the used parts.
Then I remembered, freed areas will not be overwritten and, thus some
deleted files might still be recoverable. So I do need to overwrite the
whole disk, but want to save me the time to overwrite those sectors I
already overwrote.
I know ddrescuelog can be used to transform and merge mapfiles.
So I first shifted the partition-based mapfiles to represent the
whole-disk addresses:
ddrescuelog --shift -b 4096 -o 58983168s part3.mapfile
>hdd-section-of-part3.mapfile
ddrescuelog --shift -b 4096 -o 117902336s part4.mapfile
>hdd-section-of-part4.mapfile
Now I want to merge the finished sections of these mapfiles, and this fails:
ddrescuelog -z hdd-section-of-part4.mapfile hdd-section-of-part3.mapfile
>merged
diff -u hdd-section-of-part3.mapfile merged # practically no difference
diff -u hdd-section-of-part4.mapfile merged # practically no lines in common
I expected the finished areas from partition4 to be marked as finished
in 'merged', but instead it contains just a copy of
hdd-section-of-part3.mapfile.
What am I doing wrong?
Martin Castillo
# Mapfile. Created by GNU ddrescuelog version 1.29.1
# Command line: ddrescuelog --shift -b 4096 -o 58983168s audio-pc.part3.mapfile
# Start time: 2026-01-08 00:02:40
# current_pos current_status current_pass
0x38308FF000 ? 1
# pos size status
0x00000000 0x3840300000 ?
0x3840300000 0x015AA000 +
0x38418AA000 0x00001000 ?
0x38418AB000 0xFA44B000 +
0x393BCF6000 0x0C68A000 ?
0x3948380000 0x18EFC1000 +
0x3AD7341000 0x00001000 ?
0x3AD7342000 0x00EA7000 +
0x3AD81E9000 0x00001000 ?
0x3AD81EA000 0x03673000 +
0x3ADB85D000 0x00001000 ?
0x3ADB85E000 0x04714000 +
0x3ADFF72000 0x00001000 ?
0x3ADFF73000 0x01927000 +
0x3AE189A000 0x00001000 ?
0x3AE189B000 0x00029000 +
0x3AE18C4000 0x00001000 ?
0x3AE18C5000 0x00006000 +
0x3AE18CB000 0x358F334000 ?
# Mapfile. Created by GNU ddrescuelog version 1.29.1
# Command line: ddrescuelog --shift -b 4096 -o 117902336s audio-pc.part4.mapfile
# Start time: 2026-01-08 00:02:59
# current_pos current_status current_pass
0x3FFFFF000 ? 1
# pos size status
0x00000000 0x7070C00000 ?
0x7070C00000 0x04AB0000 +
0x70756B0000 0x005C0000 ?
0x7075C70000 0x0017D000 +
0x7075DED000 0x00083000 ?
0x7075E70000 0x00521000 +
0x7076391000 0x5AA5B000 ?
0x70D0DEC000 0x54909000 +
0x71256F5000 0x00306000 ?
0x71259FB000 0x026AA000 +
0x71280A5000 0x00AD9000 ?
0x7128B7E000 0x04000000 +
0x712CB7E000 0x04000000 ?
0x7130B7E000 0x00081000 +
0x7130BFF000 0x00001000 ?
0x7130C00000 0x00080000 +
0x7130C80000 0x0C7A0000 ?
0x713D420000 0x3337DF000 +
# Mapfile. Created by GNU ddrescuelog version 1.29.1
# Command line: ddrescuelog -z hdd-section-of-part4.mapfile
hdd-section-of-part3.mapfile
# Start time: 2026-01-08 00:16:28
# current_pos current_status current_pass
0x38308FF000 ? 1
# pos size status
0x00000000 0x3840300000 ?
0x3840300000 0x015AA000 +
0x38418AA000 0x00001000 ?
0x38418AB000 0xFA44B000 +
0x393BCF6000 0x0C68A000 ?
0x3948380000 0x18EFC1000 +
0x3AD7341000 0x00001000 ?
0x3AD7342000 0x00EA7000 +
0x3AD81E9000 0x00001000 ?
0x3AD81EA000 0x03673000 +
0x3ADB85D000 0x00001000 ?
0x3ADB85E000 0x04714000 +
0x3ADFF72000 0x00001000 ?
0x3ADFF73000 0x01927000 +
0x3AE189A000 0x00001000 ?
0x3AE189B000 0x00029000 +
0x3AE18C4000 0x00001000 ?
0x3AE18C5000 0x00006000 +
0x3AE18CB000 0x358F334000 ?
