Legacy Document

Inside Macintosh: Devices /

Chapter 6 - Power Manager / Power Manager Reference

Power Manager Dispatch Routines / Controlling the Hard Disk

SetHardDiskTimeout

You can use the SetHardDiskTimeout function to set how long the computer will wait before turning off power to the internal hard disk.

void SetHardDiskTimeout(unsigned char timeout);

timeout

The amount of time that the computer will wait after the last user activity before turning off the hard disk, expressed as a number of 15-second intervals.

DESCRIPTION

The SetHardDiskTimeout function sets how long the computer will wait after the last use of a SCSI device before turning off power to the internal hard disk. The value of SetHardDiskTimeout is expressed as the number of 15-second intervals the computer will wait before turning off power to the internal hard disk. If a value of 0 is passed in, the function sets the timeout value to the default value (currently equivalent to 4 minutes).

ASSEMBLY-LANGUAGE INFORMATION

The trap is _PowerMgrDispatch ($A09E). The selector value for SetHardDiskTimeout is 5 ($05) in the low word of register D0. The hard disk timeout value to set is passed in the high word of register D0.