Apple Macintosh PowerBook 150 - Manual (Page 72)

Spinning down the hard disk
The hard disk is one of the main consumers of battery power. To extend work
time while you are using your battery, it is a good idea to turn off the hard
disk when you are not using it. This is called “spinning down” the hard disk.
To spin down the hard disk:
1 Click the HD Spin Down module in the Control Strip.
A pop-up menu appears.
2 Choose Spin Down Internal Hard Disk.
The icon shows that the hard disk is off.
The hard disk automatically turns itself back on when the computer needs it.
63 The Control Strip