Kbase P4986: What is the difference between write-throught and Write-back (write-in) controller cache ?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
4/14/2010 |
|
Status: Verified
GOAL:
Write cache explained.
GOAL:
What is the difference between write-through and Write-back (write-in) controller cache ?
FACT(s) (Environment):
All Supported Operating Systems
OpenEdge Category: Database
FIX:
Write-through
Every WRITE operation to the cache is accompanied by a write of the same data to main memory. If this is implemented, then the input/output processor need not consult the cache directory when it reads memory, since the state of main memory is an accurate reflection of the state of the cache as updated by the central processor. Although this scheme simplifies the accesses for the input/output processor, it results in fairly high traffic between central processor and memory, and the high traffic tends to degrade input/output performance. Write-back (write-in)
In this scheme, the central processor updates the cache during a write, but actual updating of the memory is deferred until the line that has been changed is discarded from the cache. At that point, the changed data are written back to main memory.