Technical data

Configuring the Computing Unit
5-7
SIMATIC Panel PC 670 Computing Unit Equipment Manual
Edition 12/01
Memory Cache
The following shortcut menu when you choose this menu option:
PhoenixBIOS Setup Utility
Item Specific Help
System Time:
ESC EXIT
System Date:
[ 15:35:32 ]
Select Item
Select Menu
+ / –
Enter Select
Change Values
Sub-Menu
F9
F10
Setup Defaults
Save and Exit
Diskette A:
[ 1.44 MB, 31/2” ]
Primary Master
[4326MB]
Primary Slave
[None]
Memory Cache:
Boot Options
Keyboard Features
[Write
Hardware Options
System Memory:
Extended Memory:
Main
Secondary Master
[CD-ROM]
Secondary Slave
[None]
[ 01/23/1999 ]
640 KB
63 MB
Controls caching of system
conventional memory and
memory above one megabyte
Disabled
Write Through
Write Back
F1 Help
Figure 5-4 Memory Cache Menu
A cache is a fast memory buffer between the CPU and main memory (DRAM).
Recurrent memory access operations are executed in the fast cache, instead of
main memory, if the function is enabled. In rare instances involving some hardware
and software combinations, it may be necessary to disable the cache because the
program execution times or delays are too short on account of the fast cache.
[Disabled] Cache is disabled
[Write Through] Write access is not completed until the entry has been made in main
memory.
[Write Back] Write access is completed immediately. The entry in main memory
takes place in the background (default)