[Bug-ddrescue] Change of pattern after interrupt

[David Morrison]

I have a failing 1TB disk and have been using ddrescue to copy it to 
another disk so I can recover the files. I am copying the whole disk 
as it has several partitions (out of a NAS box so using ext3 
filesystems). I am doing this on OS X. Both disks are connected by 
USB directly to the ports on the back of the Mac.

So I started it off using this command:

/usr/local/bin/ddrescue -n --force /dev/disk2 /dev/disk1 ./Louise.log

It ran fine for 36 hours, revealing 94 errors, and with an average 
rate of 6000kB/s.

At that stage I stopped it as I was going away for several days. It 
had copied about 750GB.

When I returned I started it up again using exactly the same command. 
After several hours it had not picked up any more errors, but the 
rate was less than 500kB/s.

Looking in the log file, I see a distinct change of pattern. Instead 
of / - + repeated, it became * + repeated. (see below)

So instead of getting non-split and bad sectors, I am getting 
non-trimmed failures. I am unsure what this means, other than that I 
have another 55 hours to go when I thought I had only about 8. :-(

0x2A254B0000  0x000C0000  +
0x2A25570000  0x0000FE00  /
0x2A2557FE00  0x00000200  -
0x2A25580000  0x29660000  +
0x2A4EBE0000  0x0000FE00  /
0x2A4EBEFE00  0x00000200  -
0x2A4EBF0000  0x05FE0000  +
0x2A54BD0000  0x0000FE00  /
0x2A54BDFE00  0x00000200  -
0x2A54BE0000  0x2A440000  +
0x2A7F020000  0x0000FE00  /
0x2A7F02FE00  0x00000200  -
0x2A7F030000  0x10A3E50000  +
0x3B22E80000  0x0000FE00  /
0x3B22E8FE00  0x00000200  -
0x3B22E90000  0x02660000  +
0x3B254F0000  0x0000FE00  /
0x3B254FFE00  0x00000200  -
0x3B25500000  0x67F810000  +
Stopped about here<<<<<<<<<<<<<<<<<<<<<
0x41A4D10000  0x00010000  *
0x41A4D20000  0x000C0000  +
0x41A4DE0000  0x00010000  *
0x41A4DF0000  0x7D4E10000  +
0x4979C00000  0x00010000  *
0x4979C10000  0x17AE80000  +
0x4AF4A90000  0x00010000  *
0x4AF4AA0000  0x001C0000  +
0x4AF4C60000  0x00010000  *
0x4AF4C70000  0x000C0000  +
0x4AF4D30000  0x00010000  *
0x4AF4D40000  0x000C0000  +
0x4AF4E00000  0x00010000  *
0x4AF4E10000  0x000C0000  +
0x4AF4ED0000  0x00010000  *
0x4AF4EE0000  0x000C0000  +
0x4AF4FA0000  0x00010000  *
0x4AF4FB0000  0x001C0000  +