Table 45 Sct Log Page And Direction; Table 46 Identify Device Information Word 206; Sct Command Transport Feature Set - Western Digital Ultrastar DC HC310 Specifications

9.18

SCT Command Transport Feature Set

9.18.1 Overview
9.18.1.1 Introduction
SMART Command Transport (SCT) is the method for the drive to receive commands using log page E0h and
transporting data using log page E1h. These log pages are used as follows:
Log page E0h
Write log page Issue Command
Read log page Return Status

Table 45 SCT Log Page and Direction

There are two ways to access the log pages: using SMART READ/WRITE LOG and READ/WRITE LOG EXT. Both
sets of commands access the same log pages and provide the same capabilities.
The log directory for log pages E0h and E1h should report a length of one. The length of log page E1h does not
indicate the length of an SCT data transfer.
If SMART is supported, but not enabled, the drive supports SMART READ/WRITE LOG for Log page E0h and E1h.
If security is enabled and password has not been issued to unlock the device, all SCT commands will fail.
9.18.1.2 Capability Definition
Capability Identification is performed by issuing Identify Device command. Word 206 of Identify Data is used to
determine if SCT is enabled and which SCT Action Codes are supported.
Word Description
206 SCT Command set support
15-12 Vendor Specific
11-6 Reserved
5 Action Code 5 (SCT Data Table) supported
4 Action Code 4 (Features Control) supported
3 Action Code 3 (Error Recovery Control) supported
2 Action Code 2 (SCT Write Same) supported
1 Obsolete
0 SCT Feature Set supported (includes SCT status)

Table 46 Identify Device Information Word 206

9.18.1.3 SCT Command Nesting and Intermingling with Standard
Commands
In general, standard ATA commands can be intermingled with SCT Commands but SCT commands cannot be
nested. SCT commands that do require a follow-on data transfer operation never have an issue with being
intermixed with any ATA commands or each other. SCT commands that do require data transfer, on the other hand,
may not be nested; that is, if a key command that requires a data transfer is issued, all data transfer – to or from the
host – must complete before another SCT command is issued. In most cases, however, ATA read/write commands
may be inserted in between SCT data transfers, that is, between complete SMART Read Log/Write Log commands.
Furthermore, any reset (power-on, software or hardware) will cause the SCT command to be aborted.
Log Page E1h
Send Data to the drive
Received Data from the drive
Western Digital Hard Disk Drive OEM Specification
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