APM(8) APM(8)
NAME
apm - Advanced Power Management 1.2 BIOS interface
SYNOPSIS
(in plan9.ini) apm0=
bind -a '#P' /dev
aux/apm [ -d device ] [ -m mountpoint ] [ -s service ]
DESCRIPTION
Aux/apm presents at mountpoint (default /mnt/apm) an inter-
face to the APM 1.2 BIOS (see apm(3)) device (the default is
to try /dev/apm, followed by #P/apm). If a service is spec-
ified, the interface will be posted at /srv/service as well.
The directory contains the following files.
battery
Contains one line for each battery in the system. Each
line lists three fields: the status (a string, one of
unknown, high, low, critical, or charging), the percent
charge remaining, and an estimate of the amount of time
left in seconds. If either or both of the last two are
unknown, the corresponding field will be zero.
ctl The ctl file is used to set power management modes for
various parts of the system. Control messages are of
the form ``device verb,'' where device is one of
system, display, storage, lpt, eia, network, and
pcmcia, and verb is one of enable, disable, standby,
and on. Enable and disable control whether power man-
agement is active for the device, while standby puts
the device into standby mode and on brings it back to
full power.
event
Reads from this file will block until an APM event has
occurred. A large enough read is guaranteed to return
an integral number of textual event descriptions, one
per line.
SOURCE
/sys/src/cmd/aux/apm.c
/acme/bin/Battery
BUGS
The verbs suspend and off should be supported but doing so
requires nontrivial help from the kernel.
Page 1 Plan 9 (printed 11/6/25)