Glossary A-B

Appendix D: Glossary

A-B

ALU

A component of the computers central processing unit where mathematical calculations are assembled and executed. CPU- intensive devices and applications rely on the ALU heavily, which in turn utilizes temporary storage in locations of CPU registers and system-level cache.

application development life cycle

Activities that surround the design, development, and implementation of computer applications. These are generally characterized by logical phases of work that progress in a contiguous fashion. Business justification, external and internal design, coding, testing, and deployment characterize these activities.

archival

The activities of moving data from an online storage device to an offline or removable storage device for long- term storage. Archiving data generally results from data that has not been accessed in a specific time period, consequently taking up valuable online disk space. It is distinguished from backup and recovery by being available for reloading into an online system for later access.

backup/recovery

Copying data from an online storage device to an offline device for protection against possible data corruption, storage outage , or site disaster. These functions differ from archival activities and functions by making a copy of the data and their time requirements in order to provide a specific data state and other information for recovery purposes.

bandwidth

A set of frequencies that designate the band of electronic wavelengths used to transmit signals within a computer system and reflect the transmission capacity of the link. This is measured by the address of the data that can be transmitted and the speed of the signals through various cycle times measured in MHz ( megahertz ).

blade computing

A method of loosely connecting discrete computer systems through a common bus. Blade computing is made up of small, powerful, fully functional, general-purpose computers that are optimized with only CPU, memory, and I/O bus components . Server blades, as they are known, are used in conjunction with an I/O backplane that supports connectivity to a common set of I/O devices, including various storage devices, network devices, and control functions.

block

A unit of data used with storage devices and systems that requires a contiguous block of data accessed with each I/O instruction of the system. Block sizes are dependent on both operating system and storage device types, but have direct relationships to the efficiency of the systems I/O operations.

bus

A system that provides the interconnection between various devices within computer systems. Generally characterized by a singular and priority-driven operation between two devices within the busone transmitting instructions and data, the other receiving them. Various bus mechanisms are used within a computer system such as the PCI bus to interconnect CPU, memory, and I/O adapters, with storage buses such as SCSI providing interconnections to multiple storage devices.

business application

A set of computer programs that automates the functions or operations of a business. This is different from utility or management applications that are computer programs which automate or enhance the management of the computer systems. Examples include systems such as backup/recovery and disk defragmentation systems.