recuperation disque macbook: read err: Input/output error

[pierre2mars]

Bonjour,

j'essai de réparer un disque dur de macbook qui a crashé.
Sous linux Testdisk me renvoie les erreurs suivantes:
TestDisk 6.14-WIP, Data Recovery Utility, March 2013
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
OS: Linux, kernel 3.2.0-44-generic-pae (#69-Ubuntu SMP Thu May 16 18:50:07 UTC 2013) i686
Compiler: GCC 4.4
Compilation date: 2013-03-31T19:24:16
ext2fs lib: 1.41.12, ntfs lib: libntfs-3g, reiserfs lib: 0.3.1-rc8, ewf lib: 20120504
/dev/sda: LBA, HPA, LBA48, DCO support
/dev/sda: size 1465149168 sectors
/dev/sda: user_max 1465149168 sectors
/dev/sda: native_max 1465149168 sectors
/dev/sda: dco 1465149168 sectors
Warning: can't get size for Disk /dev/mapper/control - 0 B - 1 sectors, sector size=512
Hard disk list
Disk /dev/sda - 750 GB / 698 GiB - CHS 91201 255 63, sector size=512 - ST9750423AS, S/N:6WS0JDY5, FW:0001SDM1
Disk /dev/sdb - 499 GB / 465 GiB - CHS 476319 64 32, sector size=512 - BUFFALO HD-PXU2, FW:0.81
Disk /dev/sr1 - 629 MB / 600 MiB - 307200 sectors (RO), sector size=2048 - BUFFALO Virtual Cdrom, FW:0.81

Partition table type default to Intel
Disk /dev/sdb - 499 GB / 465 GiB - BUFFALO HD-PXU2
Partition table type: Mac

Interface Advanced

Analyse Disk /dev/sdb - 499 GB / 465 GiB - CHS 476319 64 32
Current partition structure:

search_part()
Disk /dev/sdb - 499 GB / 465 GiB - CHS 476319 64 32
file_pread(5,5,buffer,19(0/0/20)) read err: Input/output error
file_pread(5,3,buffer,24(0/0/25)) read err: Input/output error
file_pread(5,3,buffer,71(0/2/8)) read err: Input/output error
file_pread(5,8,buffer,87(0/2/24)) read err: Input/output error
file_pread(5,8,buffer,137(0/4/10)) read err: Input/output error
avec des erreurs à l'infini..
cela est-il le signe d'un disque physiquement mort, ou bien y a-t-il un espoir?

merci de votre aide,

Pierre