Read Cache; 48-Bit Logical Block Addressing (Lba); Power Management; Self-Monitoring, Analysis, And Reporting Technology (S.m.a.r.t.) - Western Digital WD1002FBYS Technical Reference Manual

WD RE3 XL333M

3.18.2 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.
3.19

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.
48-bit Address
Bits (47:40)
LBA High (exp)
16-bit Sector Count
Bits (15:8)
Sector Count
(exp)
3.20

Power Management

This drive supports 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 drive also supports the SATA power management feature that lowers the average power
consumption of the SATA interface.
3.21

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.
3.22

Security Mode

The Security Mode feature set allows the user to create a device lock password that prevents
unauthorized hard drive access even if the drive is removed from the computer. This feature
varies by drive configuration and may not be available on all configurations.
2679-701179-A01
Bits (39:32) Bits (31:24)
LBA Mid (exp) LBA Low (exp)
Bits (7:0)
Sector Count
RELEASED 11/13/08 (WD CONFIDENTIAL)
Bits (23:16) Bits (15:8)
LBA High LBA Mid
Product Features
Bits (7:0)
LBA Low
25