Tag Archives: General Computer Terminology

RAID Array & Server Glossary of Computer Terms (Letter U)

Usable storage capacity Disk array capacity that is usable for data storage (vs. for mirroring or parity data). For example, under mirroring (RAID 1 and 0/1), usable storage remains a constant fifty percent (half of storage is always used for redundancy). This is in contrast to other RAID levels such as RAID 5, in which usable storage capacity is determined by the formula of “n-1”. “n” is the total number …

RAID Array & Server Glossary of Computer Terms (Letter W)

Write-Back Cache A caching strategy whereby write operations result in a completion signal being sent to the host operating system as soon as the cache (not the disk drive) receives the data to be written. The target disk drive will receive the data at a more appropriate time in order to increase controller performance. An optional cache battery backup can be used to protect against data loss as a result …

RAID Array & Server Glossary of Computer Terms (Letter T)

Terminator A part used to end a SCSI bus.

Termination A method of matching transmission impedance of a bus to eliminate signal reflections from the physical ends of the bus.

Throughput The number of I/O requests satisfied per unit of time (usually per second). TPC-C, Tpm-C The Transaction Processing Performance Council (TPC) is a standards organization that measures transaction throughput of systems. One of their benchmarks is Tpm-C, which reflects …

RAID Array & Server Glossary of Computer Terms (Letter S)

SCSI Small computer system interface (pronounced scuzzy). The fast, intelligent input/output parallel bus used by high-performance peripherals.

Software-based array An array in which all management functions including parity calculation (XOR) are performed by the host server CPU. These products are low priced but have high CPU utilization and limited fault-tolerant features. High-performance, low-cost array adapters are quickly replacing these inferior software-based arrays.

System disk The disk (or array) on which …

RAID Array & Server Glossary of Computer Terms (Letter P)

Parity A method of providing complete data redundancy while requiring only a fraction of the storage capacity of mirroring. The data and parity blocks are divided between the disk drives in such a way that if any single disk drive is removed or fails, the data on it can be reconstructed using the data on the remaining disk drives. The parity data may exist on only one disk drive or …