HP Vectra VEi7 Technical Reference Manual page 23

Core Components and Technologies
Mass-Storage Devices
On top of improved timing margins, the protocol of Ultra-ATA also
implements a significant feature new to ATA called Cyclical
Redundancy Check (CRC) to provide data protection verification. CRC
is calculated on a per-burst basis by both the host and the drive, and is
stored in their respective CRC registers. At the termination of each
burst, the host sends the contents of its CRC register to the drive,
which compares it against its own register's contents.
For even greater integrity, the protocol can be used at speeds slower
than its maximum 33MB/s. In these cases, signal and data integrity will
still surpass that of Fast ATA and earlier protocols at a given burst
transfer rate. In fact, the slower the Ultra-ATA transfer speeds, the
greater the integrity margins.
To access HP's white paper on the Ultra ATA/33 protocol, refer to
.
www.hp.com/desktop/library/wp.html
S.M.A.R.T. Technology
S.M.A.R.T. or Self Monitoring Analysis and Reporting Technology allows
the hard disk drive to report certain types of degradation or impending
failure. This allows the operating system to take the necessary
precautions and warn the user.
The system is comprised of software that resides both on the disk drive
and on the host computer. The disk drive software monitors the
internal performance of the motors, media, heads, and electronics of
the drive, while the host software monitors the overall reliability status
of the drive. The reliability status is determined through the analysis of
the drive's internal performance level and the comparison of internal
performance levels to predetermined threshold limits.
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