Deliberate Users may deliberately initiate a reboot. Rationale for such action may include: •
Troubleshooting: Rebooting may be used by users, support staff or system administrators as a technique to work around bugs in software, for example
memory leaks or processes that
hog resources to the detriment of the overall system, or to terminate
malware. While this approach does not address the root cause of the issue, resetting a system back to a good, known state may allow it to be used again for some period until the issue next occurs. •
Switching operating systems: On a
multi-boot system without a
hypervisor, a reboot is required to switch between installed operating systems. •
Offensive: As stated earlier, components lose power during a cold reboot; therefore, components such as
RAM that require power lose the data they hold. However, in a
cold boot attack, special configurations may allow for part of the system state, like a RAM disk, to be preserved through the reboot. The means of performing a deliberate reboot also vary and may include: •
Manual, hardware-based: A power switch or
reset button can cause the system to reboot. or through the GUI. •
Automated: Software can be scheduled to run at a certain time and date; therefore, it is possible to schedule a reboot.
Power failure Unexpected loss of power for any reason (including
power outage,
power supply failure or depletion of
battery on a mobile device) forces the system user to perform a cold boot once the power is restored. Some
BIOSes have an option to automatically boot the system after a power failure. An
uninterruptible power supply (UPS), backup battery or redundant power supply can prevent such circumstances.
Random reboot "Random reboot" is a non-technical term referring to an unintended (and often undesired) reboot following a
system crash, whose root cause may not immediately be evident to the user. Such crashes may occur due to a multitude of software and hardware problems, such as
triple faults. They are generally symptomatic of an error in
ring 0 that is not trapped by an
error handler in an operating system or a hardware-triggered
non-maskable interrupt. Systems may be configured to reboot automatically after a power failure, or a
fatal system error or
kernel panic. The method by which this is done varies depending on whether the reboot can be handled via software or must be handled at the firmware or hardware level. Operating systems in the
Windows NT family (from
Windows NT 3.1 through
Windows 11) have an option to modify the behavior of the error handler so that a computer immediately restarts rather than displaying a
Blue Screen of Death (BSOD)
error message. This option is enabled by default in some editions. == Hibernation ==