IBM 8669 - Eserver xSeries 342 Hardware Maintenance Manual page 47

System board jumper blocks
Any jumper blocks on the system board that are not shown in the illustration are
reserved. For normal operation of the system, no jumpers should be installed on
any of the jumper blocks.
Boot block jumper
If the BIOS has become damaged, such as from a power failure during a flash
update, you can recover the BIOS using the boot block jumper and a BIOS flash
diskette. See "Recovering BIOS code" on page 16 for information about the boot
block jumper.
System board switch block
The switch block contains microswitches 1-8. As shown in this illustration, switch 8
is at the top of the switch block and switch 1 is at the bottom.
The following table describes each switch.
Table 2. Switches 1-8
Switch
number Description
1- 4 Reserved
5 Clock frequency selection.
When On, the host bus speed is 100 Mhz. When Off, the host bus speed is 133 Mhz. The default
setting is off. Set this to Off to optimize the system performance.
6 Password override. (Toggling this switch allows one opportunity to enter the Setup Utility to change
or delete the power-on password.)
See "Setting the password override switch" on page 27 for more information.
1 2 3
Flash boot block
recovery jumper
(J16)
37
Installing options