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Glossary of IT Infrastructure Library Terms (ITIL®)

Glossary of Terms for the IT Infrastructure Library
Mar 4, 2004

ITSM Watch Staff


T - U


tension metrics
A set of objectives for individual team members to use to balance conflicting roles and conflicting project and organizational objectives in order to create shared responsibility in teams and between teams.


terminal emulation
Software running on an intelligent device, typically a PC or workstation, which allows that device to function as an interactive terminal connected to a host system. Examples of such emulation software includes IBM 3270 BSC or SNA, ICL C03, or Digital VT100.


terminal I/O
A read from, or a write to, an on-line device such as a VDU or remote printer.


third-line support
Where specialists' skills (e.g., development/engineer) or contracted third-party support is required.


third-party supplier
An enterprise or group, external to the customer's enterprise, which provides services and/or products to that customer's enterprise.


A condition in a virtual storage system where an excessive proportion of CPU time is spent moving data between main and auxiliary storage.


An indication of an unwanted incident that could impinge on the system in some way. Threats may be deliberate (e.g., willful damage) or accidental (e.g., operator error).


Total Cost of Ownership (TCO)
Calculated by including depreciation, maintenance, staff costs, accommodation, and planned renewal.


tree structures
In data structures, a series of connected nodes without cycles. One node is termed the "root" and is the starting point of all paths; other nodes termed "leaves" terminate the paths.


unabsorbed overhead
Any indirect cost that cannot be apportioned to a specific customer.


Underpinning Contract
A contract with an external supplier covering delivery of services that support the IT organization in their delivery of services.


unit costs
Costs distributed over individual component usage. For example, it can be assumed that, if a box of paper with 1000 sheets costs $10, then each sheet costs $.01. Similarly, if a CPU costs $lM a year and it is used to process 1,000 jobs that year, each job costs on average $1,000.


Measure of the business criticality of an incident or problem based on the impact and the business needs of the customer.


The person who uses the service on a day-to-day basis.


Utility Cost Center (UCC)
A cost center for the provision of support services to other cost centers.