apm(HW)

apm -- bootstrings for advanced power management

Syntax

apm.cmd=value

Description

Access to the BIOS-APM by boot(HW) and the kernel is controlled by the apm.cmd= bootstring. When boot runs, it executes any apm.cmd= lines found in /etc/default/boot (see boot(F)); these define the default APM handling. Any standalone apm.cmd= commands issued at the boot prompt override these settings. Alternatively, apm.cmd= may be specified as an argument to most standalone commands.

The following bootstring arguments are available:

apm.boot=test: Only boot if test evaluates to true.
apm.check=no: Do not check for APM support. Any BIOS-APM will be ignored.
apm.check=verbose: Same as yes but prints error messages.
apm.check=yes: Check for APM support (default).
apm.exists=disable: Try to disable any BIOS-APM found. The APM is not used again.
apm.exists=ignore: Do not get power status. The BIOS-APM will not be used again.
apm.exists=status: Try to get power status (default). The various internal parameters that store the status of the batteries and mains power can be tested using the apm.warn and apm.boot bootstrings. These allow booting to be aborted and a warning issued if there is insufficient power available.
A GetStatus error does not stop APM being used; in this case, the apm.warn= and apm.boot= conditions are not tested.
apm.exists=verbose: Print messages on failure; otherwise, apm.exists.status is silent on errors.
apm.warn=test: Issue a warning if the test is true. The syntax of the boolean test is defined on hasapm(ADM).

The apm.warn=test and apm.boot=test strings are used typically to prevent booting when the batteries are exhausted.

The default apm.boot test is:

   ac.online | charge.high | charge.low | (!charge.unknown & % >= 15)

which permits the boot process to proceed if AC mains power is being used or the batteries have sufficient charge.

The default apm.warn test is:

   !ac.online & (charge.low | charge.critical | (!charge.unknown & % <= 25))

which issues a warning if AC mains power is not being used and the BIOS-APM reports that the batteries are low.

The SCO OpenServer system can only use a BIOS-APM system if it supports an optional 32-bit Protected Mode interface. In the absence of such an interface, the following keywords are obeyed:

apm.no32pm=disable: Try to disable APM.
apm.no32pm=ignore: Print warning message and proceed to boot. APM will not be used (default).
apm.no32pm=ok: Same as ignore but no warning is printed.

Otherwise, if the 32-bit Protected Mode interface is available:

apm.connect=disable: Try to disable BIOS-APM interface. Proceed with boot.
apm.connect=must: Try to connect, and stop booting if this fails.
apm.connect=no: Do not use the BIOS-APM interface. Proceed with boot.
apm.connect=yes: Try to connect, and continue to boot even if this fails (default).

apm(HW)

Syntax

Description

See also