Power-On Password - IBM Personal System/2 50 Technical Reference

Power-On Password
RT/CMOS RAM has 8 bytes reserved for the power-on password and
its check character. The 8 bytes are initialized to hex 00. The
microprocessor can only access these bytes during power-on self-test
(POST). After POST is completed, if a power-on password is
installed, the password bytes are locked and cannot be accessed by a
program. A power-on password can be from 1 to 7 characters.
During power-on password installation, the password (1 to 7 keyboard
scan codes), is stored in the security space.
Power-on password installation is a function of a program contained
on the Reference diskette. Once the power-on password utility has
been installed, the password can be changed only during the POST.
When the new power-on password is installed, changed, or removed,
the password is not visible on the display.
The system unit cover can be physically locked to prevent
unauthorized access to the battery. This helps prevent unauthorized
battery removal and loss of power-on password and configuration
information.
For information about the keyboard password, see the "Keyboard and
Auxiliary Device Controller" section in the Hardware Interface
Technical Reference.
3-28 Model 50 System Board