Memory leak refers to a condition in which an incremental but steady loss of computer memory seems to be taking place. Usually, the root cause of this condition has to do with the malfunction of one or more programs. Essentially, the program fails to release memory that in no longer being used back into the pool of available memory. The result is that the used memory is not cleared for use by other computer programs, and thus diminishes the operating capacity of the computer.
Just about any type of program can be the source for memory leak. In some cases, it may be an application program, such as a database, that resides on the hard drive. At other times, the cause of the memory leak could be one of the essential program files that drive the operating system for the computer. Generally, the malfunction within the application is the result of some sort of invasion into the program proper, such as a virus or bug.
Even when the memory leak is relatively small, it can eventually cripple a system. Each time the infected application is run, the application grabs more free memory and never returns that amount of memory to the system. Over time, the amount of available memory becomes so limited that other applications are unable to obtain resources to launch or perform necessary functions, and begin to become inoperable. The end result is that the system simply shuts down and no application can run.
Many operating systems today include programming that automatically scans for memory leak and will alert the user to the problem. In addition, a number of anti-virus software programs today include components that will identify bugs or viruses that can cause a leak, and destroy them before there is a chance for the problem to do much damage. Both approaches are very helpful in preventing and dealing with incidences of memory leak.