(1) Hardware maintenance is the testing and cleaning of equipment.
(2) Information system maintenance is the routine updating of master files, such as adding and deleting employees and customers and changing credit limits and product prices.
(3) Software, or program, maintenance is the updating of application programs in order to meet changing information requirements, such as adding new functions and changing data formats. It also includes fixing bugs and adapting the software to new hardware devices.
(4) Disk or file maintenance is the periodic reorganizing of disk files that have become fragmented due to continuous updating.
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