I-Bus IBC 2600, User Manual

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Chapter 4 - Advanced Setup
4-9 IBC 2600 User’s Guide
Three options are available:
S
Select Disabled to disable L2 cache memory.
S
Select WriteThru to use the write-through caching algorithm.
S
Select WriteBack to use the write-back caching algorithm.
System BIOS Cacheable
The System BIOS, which is in the F000H memory segment, is automati-
cally shadowed to RAM for faster execution. This option indicates that
this memory segment can be read from or written to cache memory.
The Setup screen displays the system option:
System BIOS Cacheable Enabled
Available options are:
Disabled
Enabled
Video or Adapter ROM Shadow
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.
Each option allows for a segment of 16KB to be shadowed from ROM to
RAM. If one of these options is enabled and there is BIOS code present
in that particular segment, the BIOS is shadowed. Video BIOS shadow-
ing may be done in two 16KB segments at C000H and C400H. Enabling
shadowing can speed up the operation of a machine because RAM can
be accessed more rapidly than ROM and the data bus is wider to RAM.
The default setting for the video BIOS segments is
Cached.
Other 16KB ROM segments may be shadowed in the memory area from
C800H to E000H, depending upon preferences and system require-
ments. The ROM area that is not used by ISA adapter cards is allocated
to PCI adapter cards.
The Setup screen displays the system option:
XXXX,16K Shadow Cached
where XXXX is the base address of the segment of memory to
be shadowed.