Siemens SIMATIC PANEL PC 877 User Manual
Page 236
Detailed descriptions
17.6 BIOS setup
SIMATIC Panel PC 877
17-44
Operating instructions, Release 07/2006, A5E00877780-01
"Memory cache" field
The following context menu appears when you select the option “Memory cache” in the main
menu:
Figure 17-5 "Memory Cache" field
The cache is a high-speed memory buffer between the CPU and memory (DRAM).
Repeated memory access operations are executed in the fast cache, and not in the main
memory, provided the feature is enabled. In some cases it may be necessary to disable the
cache for certain types of hardware and software because intentional program runtimes or
delay times may be prevented by the fast cache.
[Disabled]
Cache is disabled
[Write Through]
Write access is not concluded until the entry has
been made in main memory
[Write Back]
Write access is concluded immediately, the entry
in main memory takes place in the background
(default)