A real time clock alarm is a feature that can be used to allow a computer to 'wake up' after shut down to execute tasks every day or on a certain day. It can sometimes be found in the 'Power Management' section of a
motherboard
A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...
's
BIOS
In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the ...
/
UEFI
UEFI (Unified Extensible Firmware Interface) is a set of specifications written by the UEFI Forum. They define the architecture of the platform firmware used for booting and its interface for interaction with the operating system. Examples ...
setup.
Wake On LAN,
Wake on ring, and
IPMI functions could also be used to start a computer after it is turned off.
In
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which i ...
, the real time clock alarm can be set or retrieved using /proc/acpi/alarm or /sys/class/rtc/rtc0/wakealarm. Alternatively th
rtcwakeutility may be used which prevents problems when using local time instead of UTC by automatically processing the ''/etc/adjtime'' file.
systemd can be used to wake a system and run a task at a specific time.
In
Microsoft Windows there are different programs which could be used to 'wake up' a computer from standby or hibernation.
Task Scheduler
Task Scheduler (formerly Scheduled Tasks) is a job scheduler in Microsoft Windows that launches computer programs or scripts at pre-defined times or after specified time intervals. Microsoft introduced this component in the Microsoft Plus! for ...
settings for power management can be used to 'Wake the computer to run this task'.
References
{{reflist
See also
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Alert on LAN Alert on LAN (AOL, sometimes AoL) is a 1998, IBM- and Intel-developed technology that allows for remote management and control of networked PCs. AOL requires a Wake on LAN adapter.
Technical details
The main idea of AOL is to send warnings to ...
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Wake-on-Ring {{short description, Signal that activates a device via a telephone connection
Wake-on-Ring (WOR), sometimes referred to as Wake-on-Modem (WOM), is a specification that allows supported computers and devices to "wake up" or turn on from a sleeping, ...
(WOR)
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Wired for Management Wired for Management (WfM) was a primarily hardware-based system allowing a newly built computer without any software to be manipulated by a master computer that could access the hard disk of the new PC to paste the install program. It could also b ...
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Wake-on-LAN
Alarms
Alarm
An alarm device is a mechanism that gives an audible, visual or other kind of alarm signal to alert someone to a problem or condition that requires urgent attention.
Alphabetical musical instruments
Etymology
The word ''alarm'' comes from t ...
Operating system technology
BIOS
Unified Extensible Firmware Interface