Siemens PANEL PC 877 operating instructions Memory cache field, Memory Cache field

Detailed descriptions 17.6 BIOS setup

"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]

[Write Through]

[Write Back]

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 background (default)

17-44	SIMATIC Panel PC 877
	Operating instructions, Release 07/2006, A5E00877780-01