In Read mode device reads block of data and transfers it thorough interface to the host controller.

The program tests blocks one by one from minimum to maximum. The program measures operation time for each block.

In Verify mode device reads block of data into drive's internal buffer only and checks for consistency, there is no data transfer through an interface connector/cable.

Verify test may work in unreliable way on USB/Flash devices.

Verify test may have restrictions on Block Size with 256, 16384 or 65536 sectors because of Windows limitations.

Author wasn't able to get stable test results with two or more simultaneous tests.

The program should not be run from a read-only device/media.

Windows XP SP3, Windows Server 2003 (with restrictions), Windows Vista, Windows 7, Windows 8, Windows 10.

Spindle start/stop function on ATA/SATA/USB/FireWire/SCSI HDD.

Reporting defect information on SCSI HDD.

Changing AAM, APM, PM parameters on ATA/SATA/USB/FireWire HDD.

Reading and analyzing identity information from ATA/SATA/USB/FireWire/SCSI HDD.

Temperature monitor for ATA/SATA/USB/FireWire/SCSI HDD.

SMART tests running on ATA/SATA/USB/FireWire HDD.

Reading and analyzing Log Pages from SCSI HDD.

Reading and analyzing SMART parameters from ATA/SATA/USB/FireWire HDD.

Reading in Butterfly mode (synthetic random read).

Reading in linear mode – same as verification but also transfers data to the host.

Verification in linear mode – fastest way to determine if your drive needs data rescue, has recoverable errors or in its perfect shape.

USB Flash (pen drives) – surface tests only.

RAID volumes made of ATA (IDE) / SATA / SCSI HDDs (surface tests only).

FireWire or IEEE 1394 HDD (see Appendix A).

External USB drives and all major USB boxes (see Appendix A).

Test disk recovery software