SMART Command Transport
SMART Command Transport or SCT is a computer storage media protocol which is used for diagnostic and reliability testing of computer storage devices, both traditional Hard Disk Drives (HDD) and Solid-State Drives (SSD). It is an extension of the previously established Self-Monitoring, Analysis, and Reporting Technology (SMART) protocol. This protocol is part of the ATA specification, which itself is a communications protocol for disk drives.
SCT is implemented as a mechanism for sending a series of commands via the SMART protocol. These commands can return various pages of data including thermal profiles, drive access statistics, SATA bus link errors, etc. The protocol uses SMART log pages to communicate back and forth.