Serious disk problem

[R Kimber]

I had an apparent disk failure the other day.  I bought a new disk, but
when copying data to it with rsync the copy failed with a " Read-only file
system" message. The disk utility suggests the health of the new disk is OK,
but an 'ls' gives "reading directory .: Input/output error"

Looking in syslog I see some errors of the form:
sd 4:0:0:0: [sdd] Unhandled error code
[ 2498.348279] sd 4:0:0:0: [sdd]  
[ 2498.348281] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[ 2498.348282] sd 4:0:0:0: [sdd] CDB: 
[ 2498.348283] Read(16): 88 00 00 00 00 01 5d 50 9f 80 00 00 00 08 00 00
[ 2498.348290] blk_update_request: 20 callbacks suppressed
[ 2498.348291] end_request: I/O error, dev sdd, sector 5860532096
[ 2498.348293] quiet_error: 80 callbacks suppressed
[ 2498.348295] Buffer I/O error on device sdd1, logical block 732566256
[ 2498.348302] sd 4:0:0:0: [sdd] Unhandled error code
[ 2498.348303] sd 4:0:0:0: [sdd]  
[ 2498.348304] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK
[ 2498.348305] sd 4:0:0:0: [sdd] CDB: 
[ 2498.348305] Read(16): 88 00 00 00 00 01 5d 50 9f 80 00 00 00 08 00 00

I have also been experiencing the occasional hiatus where the whole system
seems to freeze for a couple of seconds and then carries on.

Given that two disks have had problems, it may be a motherboard issue.
However I thought I would ask whether anyone knows of any kernel or other
software issue that might be the cause.

I'm on 14.04 - is it worth upgrading to 14.10?  Could it just be a corrupt
system file somewhere?

I'd appreciate any thoughts on this.

- Richard.
-- 
Richard Kimber