Chapter 4 AMIBIOS Setup
4 2
4 2
A d v a n c e d C M O S S e t u p O p t i o n s ,
A d v a n c e d C M O S S e t u p O p t i o n s ,
Continued
F a s t G a t e A 2 0 O p t i o n
F a s t G a t e A 2 0 O p t i o n
The settings are
Enabled
or
Disabled.
Gate A20 controls the ability to access memory addresses above 1 MB by enabling or disabling
access to the processor address line A20. To remain XT-compatible and be able to access conventional memory (from 0 - 1024K),
address line A20 must always be low, so Gate A20 must be disabled. However, some applications both enter protected mode and
shut down via the BIOS. For them, Gate A20 must be constantly enabled and disabled via the keyboard controller, which is slow.
Fast Gate A20 is an alternate method of enabling Gate A20, which speeds up programs that constantly change from addressing
conventional memory to addressing memory addresses above 1 MB. For example, enabling this option allows Microsoft®
Windows® and network operating systems execute faster.
P a s s w o r d C h e c k i n g O p t i o n
P a s s w o r d C h e c k i n g O p t i o n
This option allows the end user to configure the password option. The settings are
Setup
or
Always.
If
Always
is chosen, a user
password prompt appears every time the system is turned on. If
Setup
is chosen, the password prompt does not appear when the
system is turned on but appears when the end user runs Setup.
V i d e o R O M S h a d o w C 0 0 0
V i d e o R O M S h a d o w C 0 0 0 , 1 6 K
, 1 6 K
V i d e o R O M S h a d o w C 4 0 0
V i d e o R O M S h a d o w C 4 0 0 , 1 6 K
, 1 6 K
ROM shadow is a technique in which BIOS code is copied from slower ROM to faster RAM. The BIOS is then executed from the
RAM. These options enable ROM shadowing of the video BIOS. The settings are
Enabled
or
Disabled.
