A crash is a condition in which a computer program stops performing as expected and also stops responding to other parts of the system.
Often the crashed program will appear to freeze. Other terms for to crash are to hang, to lock up and to bomb.
Crashes can occur for application programs or for programs that constitute part of the operating system. If a program is a critical part of the operating system's kernel (i.e., the core of the operating system), the entire computer may crash, which is referred to as a system crash.
Crashes usually originate in software. They are frequently caused by bugs (i.e., errors) in the software, but they can also result from the presence of viruses and other malware (i.e., software that is developed for the purpose of doing harm to computers or via computers).
Some operating systems were highly prone to crashing, most notoriously the earlier Microsoft Windows systems such as Windows 95 through Windows ME. Others, particularly Linux and other Unix-like operating systems, are known for their robustness, that is, their ability to operate without crashing for prolonged periods and under stressful conditions.
Crashes can also result from hardware problems. One example is the accumulation of dust in the cooling fan and heat sink for the CPU (central processing unit), which can cause that chip to overheat and stop functioning. Another is aging of the processor or other semiconductor devices, including aluminum migration, in which the microscopic aluminum wiring inside the chips becomes damaged. Crashes very rarely cause actual harm to the hardware.
If an application program crashes, the best solution is usually to close the program and then to restart it if desired. It is often the case that a crashed program cannot be terminated by ordinary means, such as by pushing a software button on the display screen with a mouse click. In such situation, the program can usually be terminated by using a command such as kill or killall at the command line (i.e., in text-only mode). Another possibility, in the event that that these commands with appropriate options and arguments (i.e., input data) are not effective, is to log out and then log in again. Alternatively, the reboot command could be used to restart the entire system.
In the event of a system crash, the command line becomes inaccessible or inoperative, and thus the best choice is usually to push the reset button, which is located on the exterior of many personal computers. The other option is to turn the power off, wait for a minute or two (to minimize stress on the circuitry), and then turn it back on.
Created April 4, 2006.