SATA-Disk Module 4

APSDMxxxxX5AN-ACMXX

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© 2012 Apacer Technology Inc.

Rev. 1.1

5.6 S.M.A.R.T.

S.M.A.R.T. is an acronym for Self-Monitoring, Analysis and Reporting Technology, an open standard

allowing disk drives to automatically monitor their own health and report potential problems. It protects the

user from unscheduled downtime by monitoring and storing critical drive performance and calibration

parameters. Ideally, this should allow taking proactive actions to prevent impending drive failure.

Apacer devices use the standard SMART command B0h to read data out from the drive to activate our

SMART feature that complies with the ATA/ATAPI-7 specifications. Based on the SFF-8035i Rev. 2.0

specifications, Apacer SMART defines vendor-specified SMART Attribute IDs (A0 ~ A5, and 0C). They

represent Initial bad block count, Bad block count, Spare block count, Maximum erase count, Average

erase count and Power cycle. When the Apacer SMART Utility running on the host, it analyzes and

reports the disk status to the host before the device reaches in critical condition.

5.7 TRIM

Made of millions of NAND flash cells, SSD can be written into groups called pages in 4K size generally,

but can only be erased in larger groups called blocks of 128 pages or 512KB. These stipulations are

partially the source of many performance issues. Until an address gets used again, the SSD has to keep

track of every last bit of data that’s written on it. The ATA-TRIM instruction tilts the balance in favor of the

SSD. TRIM addresses a major part of the performance degradation issue over time that plagues all SSDs.

A TRIM enabled drive running an OS with TRIM support will stay closer to its peak performance over time.