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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


O - Q


Operational Costs
Those costs resulting from the day-to-day running of the IT services section, e.g., staff costs, hardware maintenance and electricity, and relating to repeating payments whose effects can be measured within a short time-frame, usually less than the 12-month financial year.


Operational Level Agreement (OLA)
An internal agreement covering the delivery of services which support the IT organization in their delivery of services.


All activities and measures to enable and/or maintain the intended use of the ICT infrastructure.


opportunity cost (or true cost)
The value of a benefit sacrificed in favor of an alternative course of action. That is the cost of using resources in a particular operation expressed in terms of forgoing the benefit that could be derived from the best alternative use of those resources.


The process by which functions performed by the organization are contracted out for operation, on the organization s behalf, by third parties.


The total of indirect materials, wages and expenses.


Package Assembly/Disassembly Device (PAD)
A device that permits terminals, which do not have an interface suitable for direct connection to a packet switched network, to access such a network. A PAD converts data to/from packets and handles call set-up and addressing.


page fault
A program interruption that occurs when a page that is marked "not in real memory" is referred to by an active page.


The I/O necessary to read and write to and from the paging disks: real (not virtual) memory is needed to process data. With insufficient real memory, the operating system writes old pages to disk, and reads new pages from disk, so that the required data and instructions are in real memory.


Alternative title for the BSI publication "A Code of Practice for IT Service Management".


percentage utilization
The amount of time that a hardware device is busy over a given period of time. For example, if the CPU is busy for 1800 seconds in a one-hour period, its utilization is said to be 50%.


Performance Criteria
The expected levels of achievement which are set within the SLA against specific Key Performance Indicators.


phantom line error
A communications error reported by a computer system that is not detected by network monitoring equipment. It is often caused by changes to the circuits and network equipment (e.g., re-routing circuits at the physical level on a backbone network) while data communications is in progress.


physical I/O
A read or write request from a program has necessitated a physical read or write operation on an I/O device.


prime cost
The total cost of direct materials, direct labor and direct expenses. The term prime cost is commonly restricted to direct production costs only and so does not customarily include direct costs of marketing or research and development.


The standard UK government method for Project Management.


PRINCE2 (Third Edition 2002)
The current version of PRINCE.


Sequence in which an incident or problem needs to be resolved, based on impact and urgency.


Unknown underlying cause of one or more incidents.


Problem Management
Process that minimizes the effect on customer(s) of defects in services and within the infrastructure, human errors and external events.


A connected series of actions, activities, changes, etc., performed by agents with the intent of satisfying a purpose or achieving a goal.


process control
The process of planning and regulating, with the objective of performing the process in an effective and efficient way.


A collection of activities and projects that collectively implement a new corporate requirement or function.


The organization concerned with the provision of IT services.


Quality of Service
An agreed or contracted level of service between a service customer and a Service Provider.


queuing time Queuing time is incurred when the device, which a program wishes to use, is already busy. The program therefore has to wait in a queue to obtain service from that device.