Restart (computer)
A restart (also called reboot or restart ) of a computer system ( computer ) means the restarting ( booting ) of the computer if it is already switched on. A restart is also called a warm start .
Application area
The restart is required if:
- new software has been installed (this depends on the respective program, occurs mainly under Windows operating systems);
- the operating system has received an update that cannot be integrated during operation;
- Device drivers have been installed (after new devices or hardware have been connected; also mainly under Windows operating systems);
- a running program has crashed and blocks the system;
- the operating system itself crashes and needs to be reset ;
- Another operating system is to be started (e.g. on a multiple boot system or from an external data carrier).
A restart is associated with the loss of all data in the main memory and, moreover, mostly all data only present in the temporary files of a program, provided that they can no longer be written to a permanent file. It therefore makes sense to avoid it if possible in the event of malfunctions. Due to the memory protection mechanisms used in modern operating systems, there are many ways to do this nowadays, which often lead to success. However, there are also cases where e.g. B. necessary for the correct operation of the system components of the software were damaged, changed or removed from the memory . In such a case a restart is mandatory.
In the event of a predictable restart, e.g. B. after a driver installation, it is therefore imperative to close other programs in good time and that a confirmation dialog is displayed by the initiating program immediately before the restart.
functionality
A restart can be triggered by manual input using the mouse or keyboard or by running programs (e.g. the operating system ).
Examples of manual triggering are:
- Under DOS with the key combination Strg+ Alt+ Entf(so-called clamp grip )
- Under Windows by selecting the option
Neu startenin the system shutdown dialog. (Calling up the programsshutdown.exe(XP +) orrundll32.exe(NT to Win2k)). - On some Macs with Strg+ Apfel+Power
Examples of a restart via a system command:
- Windows:
shutdown -r -f -t 0 - Linux:
shutdown -r now,rebootorinit 6 - Mac OS X:
sudo reboot - HP-UX:
rebootorshutdown -r -y now - OpenVMS:
@SYS$SYSTEM:SHUTDOWN
The PC only carries out a shortened boot procedure when it is restarted .
shut down
The first part of restart is to shutdown ( shutdown of the running system). All open applications are closed (mnemonics: Closeor Terminate, the command to release all data carrier and protocol access, and Kill, the application itself is closed) and the operating system is terminated in the same way.
If this is no longer possible due to blocking applications, there is usually only the option of pressing the reset button on the computer, which is increasingly missing on modern computers. This causes an immediate termination of all processes and the start-up (see below).
Under Linux (sometimes also with UNIX variants) the Magic SysRq key can often help in such a situation to restart the PC without damaging the file system or pressing the reset button on the computer itself.
Boot up
The second part of the restart that follows corresponds to the start-up ( booting ) of a computer if it was switched off (cold start, also reset ). On PCs with BIOS , not all routines are executed again; In some rare cases, a cold restart, i.e. a shutdown and restart of the computer, is therefore necessary. Under Windows operating systems, this happens via an interrupt set up for this purpose with the identifier Int 19h.
See also
- Energy saving #Computers, consumer electronics and small appliances - inactivity modes that don't necessarily require a restart
Web links
Individual evidence
- ↑ Shutdown . In: Windows XP Professional Product Documentation . microsoft.com
- ↑ reboot (8) . Linux man page, linux.die.net