drtest is a stand-alone program used to read a disk track by track. It was primarily intended as a test program for new stand-alone drivers, but has shown useful in other contexts as well, such as verifying disks and running speed tests. For example, when a disk has been formatted (by
format(8)), you can check that hard errors has been taken care of by running
drtest. No hard errors should be found, but in many cases quite a few soft ECC errors will be reported.
While
drtest is running, the cylinder number is printed on the console for every 10th cylinder read.