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USB disk, Linux only sees 32 of 80 GB?

I have just emptied an old 80 GB hard disk (full story in this thread, there used to be a disk manager program on it). It is now in an external USB case. However when I plug it in, Linux thinks it's only 32 GB or so? (This is in a modern computer that has no problems with large disks). I even tried plugging it into a windows machine but Windows didn't even find it (I'm no good at Windows but shouldn't it show up under "My Computer"? It did notice that new hardware was connected.)

Any ideas about how to be able to use the whole disk again? There's no old data to rescue, I just want to be able to use it for new data. :confused:

Output of dmesg after connecting the disk:

Code:

[ 6467.364000] usb-storage: device found at 8

[ 6467.364000] usb-storage: waiting for device to settle before scanning

[ 6472.364000] usb-storage: device scan complete

[ 6472.364000] scsi 3:0:0:0: Direct-Access    IC35L080 AVVA07-0        0000 PQ: 0 ANSI: 0

[ 6472.364000] SCSI device sdb: 66055244 512-byte hdwr sectors (33820 MB)

[ 6472.368000] sdb: Write Protect is off

[ 6472.368000] sdb: Mode Sense: 27 00 00 00

[ 6472.368000] sdb: assuming drive cache: write through

[ 6472.368000] SCSI device sdb: 66055244 512-byte hdwr sectors (33820 MB)

[ 6472.368000] sdb: Write Protect is off

[ 6472.368000] sdb: Mode Sense: 27 00 00 00

[ 6472.368000] sdb: assuming drive cache: write through

[ 6472.368000]  sdb:

[ 6472.380000] sd 3:0:0:0: Attached scsi disk sdb

[ 6472.380000] sd 3:0:0:0: Attached scsi generic sg1 type 0

blöa

I suspect the <32GB jumper is installed.

Quote:

Originally Posted by michaelk (Post 3227744)

I suspect the <32GB jumper is installed.

Yes, but it isn't. I double checked. It has never been set and I've always used the full 80 GB. :confused:

Solved, please explain why this worked?

I had more or less given up when I got the crazy(?) idea to try and change the jumper settings. The disk could be set to 15 or 16 heads. It has always been set to 16 so I tried changing to 15. That worked! Linux now understood that the disk has another 40 GB and I could create, format and use an 82 GB partition.

Can someone explain what the 15/16 head setting is for and if it makes a difference? Theories about why this solved my problem are also very welcome.