Product Features
WD Scorpio MX375M
24
RELEASED 11/17/10 (WD CONFIDENTIAL)
2679-771293-A01
The write cache adaptively detects random and sequential access patterns during application execution.
If a defective sector is found during a write cache operation, that sector is automatically relocated before
the write occurs.
3.11.2
Read Cache
CacheFlow implements a multiple segment read cache. Cache segments are assigned to read commands
as they are received from the host.
Each read segment consists of pre and post read sectors in addition to the host-requested sectors. This
maximizes the amount of cache data in the drive’s buffer, thereby increasing the likelihood of cache hits
and improving overall performance.
3.11.3
48-bit Logical Block Addressing (LBA)
The 48-bit Address feature set allows devices with capacities up to approximately 281 tera sectors or
approximately 144 peta bytes. In addition, the number of sectors that may be transferred by a single
command are increased by increasing the allowable sector count to 16 bits.
3.12
Power Management
The drives support the ATA power management commands that lower the average power consumption
of the hard drives. For example, to take advantage of the lower power consumption modes of the drive,
an energy efficient host system could implement a power management scheme that issues a Standby
Immediate command when a host resident disk inactivity timer expires. The Standby Immediate
command causes the drive to spin down and enter a low-power mode. Subsequent disk access
commands would cause the drive to spin up and execute the new command.
To avoid excessive wear on the drive due to the starting and stopping of the HDA, set the host’s disk
inactivity timer to no shorter than ten minutes.
The drives also support the SATA power management feature that lowers the average power
consumption of the SATA interface.
3.13
Self-Monitoring, Analysis, and Reporting Technology (S.M.A.R.T.)
S.M.A.R.T. helps you monitor a drive’s internal status through diagnostic commands at the host level.
The drive monitors Read Error Rate, Start/Stop Count, Re-allocated Sector Count, Seek Error Rate,
Power-on Hours Count, Spin-up Retry Count, Drive Calibration Retry Count, Drive Power Cycle
Count, Offline Scan Uncorrectable Sector Count, Ultra ATA CRC Error Rate, Multi-zone Error Rate,
Spin-up Time, Relocation Event Count, and Current Pending Sector Count. The hard drive updates
and stores these attributes in the reserved area of the disk. The drive also stores a set of attribute
thresholds that correspond to the calculated attribute values. Each attribute threshold indicates the
point at which its corresponding attribute value achieves a negative reliability status.
48-bit Address
Bits (47:40)
Bits (39:32)
Bits (31:24)
Bits (23:16)
Bits (15:8)
Bits (7:0)
LBA High (exp)
LBA Mid (exp)
LBA Low (exp)
LBA High
LBA Mid
LBA Low
16-bit Sector Count
Bits (15:8)
Bits (7:0)
Sector Count
(exp)
Sector Count
