Siemens SIMATIC Box PC 620 Manual page 101

"Memory Cache" Field
The following pop-up menu appears when you select the option "Memory cache" in
the main menu:
Main
System Time:
System Date:
Diskette A:
Primary Master
Primary Slave
Secondary Master
Secondary Slave
Memory Cache:
Boot Options
Keyboard Features
Hardware Options
System Memory:
Extended Memory:
F1 Help
ESC Exit
Figure 6-4 "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
the 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 runtimes or waits are too short on account of the fast cache.
[Disabled]
[Write Through]
[Write Back]
SIMATIC Box PC 620 Manual
C79000-G7076-C639-04
PhoenixBIOS Setup Utility
[ 15:35:32 ]
[ 01/23/1999 ]
[ 1.44 MB, 31/2" ]
[4326MB]
[None]
[CD-ROM]
[None]
Disabled
[Write Write Through
Write Back
640 KB
63 MB
Select Item + / – Change Values
Select Menu Enter Select
Cache is disabled
Write access is not concluded until the entry has been made in main
memory
Write access is concluded immediately; the entry in main memory
takes place in the backround (default)
Configuring the SIMATIC Box PC 620
Item Specific Help
Controls caching of system
conventional memory and
memory above one megabyte
F9 Setup Defaults
Sub-Menu F10 Save and Exit
6-9