Why should I certify a new disk—doesn’t it get tested at the factory?
Most modern disks only get limited testing during the manufacturing process. They get tested to ensure that they can read and write data correctly, spin at the correct speed and can start and stop. They are not tested to ensure that every sector can read and write correctly.
You can perform this advanced level of testing on your new disk using the SoftRAID disk certify feature. This will write a pattern to each sector on your new disk and then read it back to ensure that the pattern is identical. Testing your new disks before you use them will prevent you from using a disk which is unreliable which might result in you losing valuable files.
You can also certify a used disk before you reuse it in a different Mac or for a different volume. Certifying a disk will allow you to make sure the disk is working reliably. Remember that certifying a disk will destroy all files and data on it.