Using the System Unit
2-3
The following table summarizes the operations possible for each key mode switch position:
Key Mode Switch Position
Operation
Normal
Secure
Service
Reset
Yes
No
Yes
Keyboard Active
Yes
Yes
Yes
Keyboard Debug/Dump/Loading
Operating System
No
No
Yes
Normal IPL
Yes
No
No
Service IPL
No
No
Yes
Covers Locked
Yes
Yes
No
•
The Normal position is used for attended operation, which is the usual or normal
placement of the key mode switch when an operator is present and in control of the
operation at the system unit. The Reset button is active. The IPL proceeds according to
the list of devices established during the configuration of the operating system.
Note: If an operating system has never been installed, use the Service position for initial
installation.
Attention: Pressing the Reset button (when the mode switch is in the Normal or Service
position) can cause data to be damaged or lost if the operating system is still running. For
a description of the Reset button operation, see the
AIX Version 4 Problem Solving Guide
and Reference before pressing it while the key mode switch is in the Normal position.
•
The Secure position is used for unattended operation in an open environment. For
example, the system unit can be used for process control in a manufacturing area where
an operator, responsible for the system operation, is not located in the immediate area.
In the Secure position, the Reset button is not active. The Secure position prevents any
IPL. With the key mode switch in this position, someone cannot accidentally press the
Reset button and cause a loss of data.
Notes:
1. If you start the system unit while the key mode switch is in the Secure position, the IPL
of the system unit stops and the 3-digit display displays
200
. The system does not
perform any further operations until the key mode switch is set to the Normal or
Service position.
2. When the key mode switch is moved to the Secure position after IPL, all system
functions continue to operate to allow data entry and retrieval.
•
The Service position is used for attended operation when hardware or software service is
conducted. The Service position activates operating system keyboard sequences that
support error determination (debug) and storage printout (dump). In the Service position,
the system unit attempts to perform an IPL from the diskette drive. If a diskette is not
present in the diskette drive or if there is no IPL record on the diskette, the system
attempts to perform an IPL from the predetermined list of IPL devices.
Note: If the 3-digit display displays
200
, pressing the Reset button within 20 seconds will
cause the Main Menu to display.