Patch is software designed and developed to fix the bugs (security errors, and other bugs) of a computer system. It is also used for updating the computer program and its data in a way to ensure high performance and usability. A poorly designed patch can create new issues as well.
Patch management is a methodology, wherein a patch is developed and implemented on a system at slated time period. Technically, the size of the patches differ from a few kilobytes to hundreds of megabytes. Patches are distributed as executable files, wherein the user program is modified by changing the binary file (either by adding essential changes, or by completely removing it).
Patches derived from an open source projects, modifies the source code. Different nomenclatures are used for the term “patch”. Heavy patches used for modifying the program are often circulated as service update or as service packs.
Hot Patching is the application of patches that works without the need of shutting down and restarting the concerned system or the program.