GNU DDRescue 1.25 to copy a failed to be recognized 4.0TB HDD to rescue. Completed "mapfile", but what do I do with this mapfile file?

I have :

• Gigabyte X399 Aorus Gaming 7
• AMD Thread Ripper 1950X
• 32GB Ram
• O/S=OpenSuSE Leap 15.2
• 2 (new) X 4.0TB WD(Blue)[Raid 1]
• 2 (corrupted existing) X 4.0TB WD(Blue)[ex-Raid 1] HDDs
• Also QNAP TS/431X2 with 4 X 3.0TB WD(Red) that was being setup as a Backup system when a storm surge interruption occurred causing a loss of all data and CyberPower UPS was damaged.

Check testing has proven all the equipment is good. External 10.0TB Seagate expansion USB as a backup (temporary) HDD to save files and partitions etc. I needed to recover my valuable data and have the

24/9/20       mapfile       1
# Mapfile. Created by GNU ddrescue version 1.25
# Command line: ddrescue -f -r3 /dev/sdf /dev/sdi2 mapfile
# Start time:   2020-09-22 22:58:05
# Current time: 2020-09-24 11:14:50
# Finished
# current_pos  current_status  current_pass
0x10E23356E00     +               3
#      pos        size  status
0x00000000  0x2D9E8000  +
0x2D9E8000  0x00001000  -
0x2D9E9000  0x00FA9000  +
0x2E992000  0x00001000  -
0x2E993000  0x10DF49C3000  +
0x10E23356000  0x00001000  -
0x10E23357000  0x2955E47F000  +

This mapfile tells you where the unreadable areas (3 areas in your case) on your disk are located.

As they share the same size (0x00001000) you copied a disc which probably has a physical (real) sector size of 4096 bytes.

If you divide each address by the logical (emulated) sector size (that is the sector size your drive pretends to have in communication with your mainboard), you get the starting sector number of your failed areas.

If you divide the size information by the logical (emulated) sector size you get the length of the failed ares in terms of number of sectors.

Both information, starting sector number and length of a unreadable area can then be used to determine if this unreadable area is unused or part of an existing file on disc.