Power Macintosh 8600: Hard Disk Spins Up During Sleep

I have a Power Macintosh 8600 running Mac OS 8.0 or Mac OS 8.1 and when I choose sleep from the Special menu, the machine spins down the hard disk waits a second or two, turns off the display, and spins the hard disk up again.

I would expect the hard disk to not spin up until I press a key on the keyboard. Why is this happening?
This issue is specific to the 8600 series and only occurs with Mac OS 8.0 and Mac OS 8.1. Apple is investigating a solution. If you remove the Energy Saver extension, when sleep is chosen the disk will spin down, and only when a key is pressed will it spin up again.

However, you will not be able to use the scheduled Sleep/Startup/Shut Down features without the extension. Basically, you will need to decide if immediate sleep with hard drive spin down is more important than the scheduled options.
Published Date: Feb 18, 2012