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Features
Writer: Pamela King Project: SMART-2DH Array Controller Reference Guide Comments: 295469-002
File Name: B-CH01.DOC Last Saved On: 2/27/98 11:23 AM
COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED
NOTE
: The SMART-2DH Controller Array Accelerator is equipped with a
switch that may be activated to fine tune system performance. See Appendix
E for further information.
The Array Accelerator is made of ECC (Error Checking and Correcting)
memory, providing a high level of data integrity. ECC memory detects and
corrects hard and soft memory errors without affecting performance.
The Array Accelerator is backed up with onboard rechargeable batteries,
ensuring that the data temporarily held (cached) there is safe even with
equipment failure or power outage. This is particularly important for data that
has been cached by a posted-write, but has not yet been written to the hard
drives. The batteries preserve data in the Array Accelerator for up to four days.
IMPORTANT:
The rechargeable batteries on a new SMART-2DH Array
Controller may be discharged when the board is first installed. During
server power up with discharged Array Accelerator batteries, Power-On
Self-Test (POST) displays the code “1794,” indicating that the Array
Accelerator is disabled. This is not a problem that requires action on your
part. The Array Accelerator is automatically enabled when the batteries are
charged to 90% of their capacity.
It may take up to 36 hours for the internal circuitry to charge the batteries
fully. During this time, the Array Accelerator will be disabled, but the
SMART-2DH Array Controller will function properly, although without the
performance advantage of the Array Accelerator.
The Array Accelerator, with backup batteries, is located on a removable
daughter board. In the unlikely event of failure, the Array Accelerator can be
detached from the failed SMART-2DH Array Controller and attached to a
replacement SMART-2DH Array Controller. If the configuration information
stored in the Array Accelerator matches that stored on the drives, any valid
posted-write data being held in the cache is automatically written to the drives
attached to the replacement Array controller. Thus, data being held in the
Array Accelerator memory can be recovered despite failure of the main
SMART-2DH Array Controller board.