Utility software is software designed to help analyze, configure, optimize or maintain a computer. It is used to support the computer infrastructure - in contrast to application software, which is aimed at directly performing tasks that benefit ordinary users. However, utilities often form part of the application . For example, a batch job may run user-written code to update a database and may then include a step that runs a utility to back up the database, or a job may run a utility to compress a disk before copying files. Although a basic set of utility programs is usually distributed with an operating system (OS), and this first party utility software is often considered part of the operating system, users often install replacements or additional utilities. Those utilities may provide additional facilities to carry out tasks that are beyond the capabilities of the operating system. Many utilities that might affect the entire computer system require the user to have elevated privileges, while others that operate only on the user's data do not. System utilities Anti-virus utilities scan for computer viruses and block or remove them. Clipboard managers expand the clipboard functionality of an operating system. Computer access control software grants or denies requests for access to system resources. Debuggers typically permit the examination and modification of data and program instructions in memory and on disk. Diagnostic programs determine and report the operational status of computer hardware and software. Memory testers are one example. Network utilities analyze the computer's network connectivity, configure network settings, check data transfer or log events. Package managers are used to configure, install or keep up to date other software on a computer. Registry cleaners clean and optimize the Windows Registry by removing old registry keys that are no longer in use. System monitors monitor resources and performance in a computer system. System profilers provide detailed information about installed software and hardware. Storage device management utilities Backup software makes copies of all information stored on a disk and restores either the entire disk (aka Disk cloning) in an event of disk failure or selected files that are accidentally deleted or corrupted. Undeletion utilities are sometimes more convenient. Disk checkers scan an operating hard drive and check for logical (filesystem) or physical errors. Disk compression utilities transparently compress/uncompress the contents of a disk, increasing the capacity of the disk. Disk defragmenters detect computer files whose contents are scattered