hopefully simple query regarding dd

[Dave]

On Thursday 13 April 2017 11:08:23 tech-lists wrote:
>   5 Reallocated_Sector_Ct   PO--CK   183   183   140    -    143
> 197 Current_Pending_Sector  -O--CK   001   001   000    -    65216
> 198 Offline_Uncorrectable   ----CK   100   253   000    -    0
> 196 Reallocated_Event_Count -O--CK   196   196   000    -    4

Reallocated sectors are sectors where the HDD firmware was unable
to reliably read the data repeatedly and so has used the one or
more successful reads to move the data to a spare track.

Pending sectors are sectors where there has been one or more 
unsuccessful reads followed by a successful read.  This will
remain pending unless and until the HDD gets a successful
first time read, in which case it goes back to ok, or fails
again and it gets remapped.

Basically, it all means the HDD is almost certainly on it's
way out and should be replaced if you value your data.

For testing an HDD, personally I'd use either the manufacturers
diags tools or HDAT2 (booted from FreeDOS).  Both Seagate and WD
have DOS bootable tools on their websites, Seatools (Seagate)
and Dlgdiags (WD).  Others probably do too, but HDAT2 is universal
and also does various surface scans including read/write/verify
which will "refresh" your data with error checking, unlike the
more dangerous dd.  HDAT2 may require you to manually switch the
HDD mode to IDE from AHCI because on some BIOS it fails to perform
the switch itself.  Another option to HDAT2 is MHDD.  Similar
features but less menu oriented like HDAT2.