Using badblocks to test and wipe disks

Non destructive (read only) test, optimized for 1G RAM:

badblocks -b 4096 -c 98304 -p 0 -s /dev/sda

Destructive read/write test (use caution!):

 badblocks -b 4096 -c 98304 -p 0 -w -s /dev/sda