Functional description, Advanced flash management, Defect and error management – Western Digital WD 2TB 3D NAND SATA III 2.5" Internal SSD (Retail) User Manual
Page 9: Wear leveling, Functional description advanced flash management, Defect and error management wear leveling
Functional Description
The WD Blue 3D NAND SATA SSD supports the following features:
▪ Support for multi-stream – improves user experience in multitasking systems
▪ Support for TRIM command – sustains drive’s high performance over time
▪ Minimal write
amplification
– increases endurance and performance
▪ Tiered caching, including use of allocated SLC blocks
▪ Support for ATA register and command set (ATA-8/ACS-4 standard)
▪ SMART feature support
▪ Error recovery using Error Correction Code (ECC)
▪ Self-management of NAND memory defects
▪ Advanced power management for low-power operation, including DEVSLP
capability
▪ Error-management system - provides a last line of data protection
▪ Dynamic and static wear leveling to extend the life of the WD Blue 3D NAND
SATA SSD
Advanced Flash Management
Defect and Error Management
The WD Blue 3D NAND SATA SSD contains an enhanced defect and error
management system that is similar to systems found in hard disk drives (HDDs). If
necessary, the device will rewrite data from a defective block to a good block. This
action is completely transparent to the host and does not consume any user data
space.
The WD Blue 3D NAND SATA SSD soft error rate
specification
is superior to the HDD
specification.
In the rare case when a read error occurs, the drive uses Error
Detection Code (EDC) and Error Correction Code (ECC) algorithms to recover the
data. These defect and error management systems give it unparalleled reliability.
The WD Blue 3D NAND SATA SSD also includes a robust error handling mechanism
which can recover errors that other traditional error correction mechanisms cannot.
This mechanism can leverage a hardware XOR core to calculate the extra parity
on-
the-fly
with minimal impact in performance.
Wear Leveling
Wear leveling is an intrinsic part of the erase pooling functionality. NAND-based
SSDs use dynamic and static wear leveling and automatic block management to
ensure an even distribution of write/erase cycles throughout the entire device.
These processes guarantee high data reliability and maximize
flash
life expectancy.
Wear leveling is done between all TLC blocks and separately between all SLC
blocks.
9
Non-operational storage temperature does not guarantee data retention.
Introduction
WD Blue 3D NAND SATA SSD
User Manual
4