The System Log Says, "end_request: I/O error, ...."
This error message, and messages like it, almost always indicate a
hardware error with a hard drive.
This commonly indicates a hard drive defect. The only way to avoid
further data loss is to completely shut own the system. You must also
make sure that whatever data is on the drive is backed up, and restore
it to a non-defective hard drive.
This error message may also indicate a bad connection to the drive,
especially with home brew systems. If you install an IDE drive, always
use new ribbon cables. It's probably is a good idea with SCSI drives,
In one instance, this error also seemed to coincide with a bad ground
between the system board and the chassis. Be sure that all electrical
connections are clean and tight before placing the blame on the hard
[Peter Moulder, Theodore Ts'o]