User's Manual

Glossary 91
SubVendor ID
A controller property that lists additional vendor ID information about the
controller.
Uncorrectable Error Count
A controller property that lists the number of uncorrectable errors detected on
physical disks connected to the controller. If the error count reaches a certain
level, a physical disk will be marked as
Failed .
Vendor ID
A controller property indicating the vendor-assigned ID number of the
controller.
Vendor Info
A physical drive property listing the name of the vendor of the drive.
virtual disk (VD)
A storage unit created by a RAID controller from one or more physical disks.
Although a virtual disk can be created from several physical disks, it is seen by
the operating system as a single disk. Depending on the RAID level used, the
virtual disk can retain redundant data in case of a disk failure.
Virtual Disk State
A virtual disk property indicating the condition of the virtual disk. Examples
include
Optimal and Degraded .
write-back
In write-back caching mode, the controller sends a data transfer completion
signal to the host when the controller cache has received all the data in a disk
write transaction. Data is written to the disk subsystem in accordance with
policies set up by the controller. These policies include the amount of
dirty/clean cache lines, the number of cache lines available, and elapsed time
from the last cache flush.