Vendor-provided diagnostic tools

Hard drive vendors offer diagnostic tools only for regular (rotational) hard drives. SSD software is mostly limited to firmware updates.

Western Digital

Western Digital provides WD Drive Utilities to test various WD hard disks. The program offers several tests:

Quick test - collects S.M.A.R.T. data from a hard drive and quickly detects whether a hard disk is defective or not.
Extended test - performs the deep scan of a hard disk to detect bad sectors. By default, the test doesn't destroy data unless you intentionally select an option to "repair" found bad sectors.
Write zeroes - fills a hard disk with zeroes. It can work in two submodes:
- quick erase - fills first and last sectors of a hard disk with zeroes,
- full erase - fills all sectors on a hard disk with zeroes.

Samsung

Samsung provides the Magician Software to test internal hard disks made by Samsung. It is recommended to use the tool before you are going to start the RMA process (returning the drive under warranty).

Main functions of the Magician Software:

Drive Information.
Integrative Drive Health Check.
S.M.A.R.T. Check and others.

Fujitsu/Toshiba

Fujitsu/Toshiba doesn't provide a tool to test a hard drive.

Seagate and Maxtor

Seagate provides Seatools to diagnose both internal and external hard drives. The tool works not only with hard disks produced by Seagate and Maxtor but with disks from other vendors as well. The main purpose of Seatools is to identify defective disks which can be replaced under warranty.

Seatools can do the following:

provide Drive Information
S.M.A.R.T. Check
Short Drive Self Test
Long Drive Self Test
Short Generic test
Long Generic test
Advanced Tests

All tests for internal disks are read-only, i.e. data safe. In case of an external disk, there are two unsafe procedures: long generic test with enabled option to repair bad sectors and USB Erase Boot Tracks, which zero-fills the beginning of an USB disk to erase previous partition information.

Hitachi

Hitachi provides Drive Fitness Test which is designed to test hard drives made by Hitachi/IBM and many other vendors. The tool is DOS-based and its main purpose is to detect defective Hitachi/IBM disks which should be returned under warranty.

DFT can do the following:

Quick Test - reads sectors on a hard disk selectively to detect corrupted sectors. If this test is used with default settings, then the test is a data-safe because the user's data is not overwritten. However, when the tool encounters corrupted sectors, it offers either to ignore them or to run Erase Disk; the latter will erase user data.
Advanced Test - the same as Quick Test, the only difference is that it reads all sectors on a hard drive.
Exerciser - the same as Advanced Test, but it can do several passes.
Erase Boot Sector - zero-fills a hard drive boot sector.
Erase Disk - completely zero-fills a hard disk.

Hitachi also offers one more tool to diagnose a hard drive - OGT (On site Analysis tester for Generic Tool). OGT works only with Hitachi drives and it is used solely to detect defective drives which should be returned under warranty. Testing a disk with OGT is not data safe because when OGT encounters bad sectors, it tries to fix them, and that can result in a data loss.