IBM R31 - Manual (Page 59)

meaning of each icon:
7
6
Symbol Color Meaning
(1) Drive in use Green 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.
(2) Numeric lock Green 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.
MT 2656, 2657, 2676 53