Datasheet

IBM 128 GB and 256 GB SATA 2.5" MLC Entry SSDs 2
Part number information
Table 1 lists the information for ordering part numbers and feature codes.
Table 1. Ordering part numbers and feature codes
Description Part number Feature code
IBM 128GB SATA 2.5" MLC HS Entry SSD 90Y8648 A2U4
IBM 128GB SATA 2.5" MLC SS Entry SSD 90Y8668 A2UB
IBM 256GB SATA 2.5" MLC HS Entry SSD 90Y8643 A2U3
IBM 256GB SATA 2.5" MLC SS Entry SSD 90Y8663 A2UC
The part numbers include the following items:
One SSD mounted on a 2.5" hot-swap drive tray (HS Entry SSDs) or 2.5" simple-swap drive tray (SS
z
Entry SSDs)
Support Flyer for SSD
z
Warranty Flyer
z
Important Notices Flyer
z
Features
2.5-inch industry standard form factor that fits into a conventional disk drive bay
z
SATA 6 Gbps interface
z
Utilization of industry-leading 25 nm MLC
z
Cost-effective MLC NAND technology with high read performance
z
Enterprise Data Path Protection to ensure NAND integrity
z
Endurance: 72 TB of total bytes written (TBW) at 90% full disk based on predefined usage pattern
z
(see explanation below)
Energy-saving 2.5 - 3.5 watt power consumption per drive
z
Absence of moving parts reduces potential failure points in the server
z
Native command queuing support
z
Self-monitoring, analysis, and reporting technology (SMART) command set
z
It is important to distinguish these 128 GB and 256 GB entry-level drives from the Enterprise drives.
Enterprise drives have much higher write endurance, and as a result can withstand a greater number of
writes over the lifetime of the device compared to entry-level drives. SSD write endurance is typically
measured by the number of program/erase (P/E) cycles, that the drive incurs over its lifetime, listed as
TBW in the device specification.
The TBW value assigned to a solid-state device is the total bytes of written data (based on the number of
P/E cycles) that a drive can be guaranteed to complete (% of remaining P/E cycles = % of remaining
TBW). Reaching this limit does not cause the drive to immediately fail. It simply denotes the maximum
number of writes that can be guaranteed. A solid-state device will not fail upon reaching the specified
TBW. At some point based on manufacturing variance margin, after surpassing the TBW value, the drive
will reach the end-of-life point, at which the drive will go into a read-only mode. Because of such behavior
by entry-level solid-state drives, careful planning must be done to use them only in read-intensive
environments to ensure that the TBW of the drive will not be exceeded prior to the required life
expectancy.