IBM thinkpad r30 Hardware Maintenance Manual page 62

meaning of each icon:
7
6
Symbol
(1) Drive in use
(2) Numeric lock
56
ThinkPad R30/R31 HMM
Color
Green
Green
Meaning
Data is being read from or
written to the hard disk. Do
not enter standby mode or
power off the computer
when this indicator is on.
The numeric keypad on the
keyboard is enabled. You
enable or disable the
keypad by pressing and
holding the Shift key, and
pressing the NumLk key.
For details, see the User's
Reference.