overhead

overhead

(1) The amount of processing time used by system software such as the operating system, database manager or network protocols.

(2) In communications, the additional codes transmitted for control and error checking, which take time to process.

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overhead

Nautical the interior lining above one's head below decks in a vessel

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overhead [′ō·vər‚hed]

(chemical engineering)

Pertaining to fluid (gas or liquid) effluent from the top of a process vessel, such as a distillation column.

(computer science)

The time a computer system spends doing computations that do not contribute directly to the progress of any user tasks in the system, such as allocation of resources, responding to exceptional conditions, providing protection and reliability, and accounting.

(industrial engineering)

fixed cost

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1.		overhead - Resources (in computing usually processing time or storage space) consumed for purposes which are incidental to, but necessary to, the main one. Overheads are usually quantifiable "costs" of some kind. Examples: The overheads in running a business include the cost of heating the building. Keeping a program running all the time eliminates the overhead of loading and initialising it for each transaction. Turning a subroutine into inline code eliminates the call and return time overhead for each execution but introduces space overheads.
2.	(communications)	overhead - information, such as control, routing, and error checking characters, that is transmitted along with the user data. It also includes information such as network status or operational instructions, network routing information, and retransmissions of user data received in error.
3.		overhead - Overhead transparencies or "slides" (usually 8-1/2" x 11") that are projected to an audience via an overhead (flatbed) projector.