# Command: idlehalt

      IDLEHALT activates built-in kernel energy saving functionality if
      n is not 0.
      IDLEHALT is a CONFIG.SYS / FDCONFIG.SYS command.

## Syntax:

      idlehalt=n
        where n can be -1, 0, 1 or higher (default 0)

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## Options:

      - none -

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## Comments:

      IDLEHALT activates built-in kernel energy saving functionality if
      n is not 0. Value -1 enables all hooks, 1 enables only "safe" hooks,
      CPU halted only if kernel is waiting for CON char device input.
      Further hooks for n=-1 and n>0 depend on the kernel version:
      In addition to the safe hooks, other hooks can get activated, for example
      one for int 0x2f, ax=0x1680 "release time slice".
      Note: In rare cases, entering or leaving HLT mode (which causes big
      changes in CPU power consumption) can cause crashes if cheap power
      supplies or mainboards cannot properly filter the transients.
      Underclocking the whole system may help.
      Linux always does a few HLT at boot time, to force a hang on buggy
      systems early (boot with no-hlt to disable HLT).
      P90 may have buggy HLT? www.tavi.co.uk/ps2pages/ohland/halt.html
      IDLEHALT is a command internal to kernel.sys and needs no other file
      in order to work.

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## Examples:

      IN CONFIG.SYS / FDCONFIG.SYS:
        idlehalt=1

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## See also:

      config.sys
      fdconfig.sys

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## File:

      Please read this command's lsm file also.
      You will find the updated version (internet) here and
      the version described in this manual page here.
      The lsm file contains information about the name of the programmer,
      the download site, and some other command related information.

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      Copyright © 2003 Robert Platt, updated 2008 by W. Spiegl.

      This file is derived from the FreeDOS Spec Command HOWTO.
      See the file H2Cpying for copying conditions.