Lenovo ThinkServer RD230, Software User'S Manual

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MegaRAID SAS Software User Guide B-1
Appendix B
Glossary
access policy A virtual drive property indicating what kind of access is allowed for a
particular virtual drive. The possible values are
Read/Write , Read Only ,
or Blocked.
alarm enabled A controller property that indicates whether the controller’s onboard
alarm is enabled.
alarm present A controller property that indicates whether the controller has an onboard
alarm. If present and enabled, the alarm is sounded for certain error
conditions.
array See drive group .
BBU present A controller property that indicates whether the controller has an onboard
battery backup unit to provide power in case of a power failure.
BGI rate A controller property indicating the rate at which the background
initialization of virtual drives will be carried out.
BIOS Basic Input/Output System. The computer BIOS is stored on a flash
memory chip. The BIOS controls communications between the
microprocessor and peripheral devices, such as the keyboard and the
video controller, and miscellaneous functions, such as system messages.
cache Fast memory that holds recently accessed data. Use of cache memory
speeds subsequent access to the same data. When data is read from or
written to main memory, a copy is also saved in cache memory with the
associated main memory address. The cache memory software monitors
the addresses of subsequent reads to see if the required data is already
stored in cache memory. If it is already in cache memory (a cache hit),
it is read from cache memory immediately and the main memory read is
aborted (or not started). If the data is not cached (a cache miss), it is
fetched from main memory and saved in cache memory.