FDAPM is an advanced Power Management tool.
(none) If no options are given, default is to show both the
INFO and the STATS output (if shell loaded, otherwise,
when loaded through INSTALL, default is to do APMDOS).
APMoff Disable plain BIOS APM energy saving mode. MS POWER syntax
compatibility alias: "OFF".
OFF Same as APMoff, for compatibility with MS power.
APMbios Enable plain BIOS APM energy saving mode. MS POWER syntax
compatibility alias: "STD".
STD Same as APMbios, for compatibility with MS power.
APMDOS This should give you maximum energy savings. It is the
only mode that causes FDAPM to stay resident in RAM.
To stop, select APMbios/APMoff.
ADV:MAX Maximum energy savings, for compatibility with MS power.
ADV:MIN Minimum energy savings, for compatibility with MS power.
ADV:REG Restricted energy savings, for compatibility with MS power.
INFO Show information about APM status. Displays things like
battery fill percentage.
STATS Show information about APM status / APMDOS. Displays things
like CPU busy time percentage, if resident FDAPM or POWER
is loaded in memory.
FLUSH Flushes the disk caches (writes back data to disk).
SPINUP Wakes up IDE disks (again).
SPINDOWN Flushes the disk caches and stops IDE disks on the first 2
IDE controllers. Use at your own risk. The disks will spin
up again when you use them again. The disks have builtin
"intelligence" for that. To save energy automatically, you
can often use a BIOS setup option which tells the disk at
boot time that it can spin down itself (it has a builtin
timer!) whenever it has not been accessed for a while.
ACPIOFF As POWEROFF but explicitly uses ACPI instead of APM. Note
that the classic functions will use ACPI, too, if no APM
BIOS support is present. The system is placed into S5
soft-off after flushing caches and spinning down disks.
Useful to compare APM / ACPI handling.
STANDBY Flushes the disk caches, enter stand-by mode. Requires APM
or ACPI and an ATX or newer power supply.
SUSPEND Flushes the disk caches, stops (will auto wake up) IDE disks,
suspends system. Useful if you have a BIOS with suspend to
disk, to avoid spinning the disks right before suspend needs
them. Requires APM or ACPI and an ATX or newer power supply.
PURESUSP As SUSPEND / POWEROFF, but does not stop IDE disks first.
Requires APM or ACPI and an ATX or newer power supply.
POWEROFF Flushes the disk caches, stop IDE disks, power off VGA and
system. Requires APM or ACPI and an ATX or newer power
PUREOFF As SUSPEND /POWEROFF, but does not stop IDE disks first.
Useful if your BIOS would otherwise wake up the disk right
before cutting off power (ouch). Requires APM or ACPI and
an ATX or newer power supply.
VGAoff Switches EGA/VGA DPMS screen off (no auto wake up!).You have
to type FDAPM VGAon or to reboot to switch on. VGAoff is no
screensaver. Use idledpms as screensaver instead.
VGAon Switches EGA/VGA DPMS screen on again. Just pressing a key
after using the VGAoff function will NOT enable video again,
this is not a screen saver. It is only a way to turn video
on and off without any kind of system monitoring or
ZapStats Clear STATS counters.
SPEEDn Set system speed to n/8 (n * 12,5%) of max. (0 halts until
'power' pressed). Use SPEED9 to show current setting.
SPEED9 is the recommended way to test if your system does
use ACPI in a FDAPM compatible way. Requires ACPI.
SPEED0 Speed 0 will put the system into S1 standby (press the ATX
power or sleep button to continue) CPU-wise. None of the
other devices will sleep. Use the PCISLEEP tool if you want
to do experiments with PCI Power Management.
COLDboot Do a reboot with BIOS tests (POST) (after flushing the disk
caches) by telling the 8042 keyboard controller to pulse
the hardware reset circuits. Very similar to a real cold
reboot - only in rare cases, pressing the reset button or
power-cycling the computer will give you a "colder" reset.
WARMboot Do a reboot without BIOS tests (POST). Usually safe but can
crash if you use incompatible protected mode software, like
some versions of EMM386. Flushes the disk caches before
HOTboot Try a reboot at once using int 19h (will often crash!).
Before attempting the reboot, FDAPM tells caches to flush
(write back data to disk) themselves and waits for a moment.
HELP Shows the help.
/? Shows the help.
FDAPM is a replacement for MS-DOS Power.
APM: Advanced Power Management.
ACPI: Advanced Configuration and Power Interface.
ATX: Advanced Technology Extended.
DPMS: Display Power Management Signaling.
Case is irrelevant, "-" or "/" are not needed.
All harddisk sleep/standby/off related options automatically add a
delay to give the harddisk time to change state. All of those and all
reboot related options tell caches to write back dirty buffers to
disk before the real action begins.
Please read fdapm.txt in the fdapm packet for more information, see:
fdapm apmdos gives you maximum energy savings
fdapm speed2 sets speed to 2x12,5% = 25% of maximum speed e.g. for
Copyright © 2004 Eric Auer, updated 2008 and 2022
by W. Spiegl.
This file is derived from the FreeDOS Spec Command HOWTO.
See the file H2Cpying for copying conditions.