This preview shows page 1. Sign up to view the full content.
Unformatted text preview: d ﬁle system such as AFS, the local disk serves as a cache that is managed by the AFS client process running on the local machine. In most cases, caches operate automatically and do not require any speciﬁc or explicit actions from the program. 6.3.2 Summary of Memory Hierarchy Concepts
To summarize, memory hierarchies based on caching work because slower storage is cheaper than faster storage and because programs tend to exhibit locality. ¯ ¯ Exploiting temporal locality. Because of temporal locality, the same data objects are likely to be reused multiple times. Once a data object has been copied into the cache on the ﬁrst miss, we can expect a number of subsequent hits on that object. Since the cache is faster than the storage at the next lower level, these subsequent hits can be served much faster than the original miss. Exploiting spatial locality. Blocks usually contain multiple data objects. Because of spatial locality, we can expect that the cost of copying a block after a miss will be amo...
View Full Document
- Spring '10
- The American