Data Delivery: It explains two methods for delivering data from the disk cache to the requesting process: memory-to-memory transfer or using shared memory with pointers, the latter being more efficient and allowing shared access.
Replacement Strategy: When a new sector is brought into the disk cache, an existing block must be replaced. Common strategies include Least Recently Used (LRU), where the least recently accessed block is replaced, and Least Frequently Used (LFU), which replaces the block with the fewest references. However, LFU can be less effective due to the influence of locality on reference counts.
Frequency-Based Replacement: An advanced technique divides the cache into sections (new, middle, and old) to mitigate LFU's issues, allowing blocks time to build up reference counts before being eligible for replacement. This approach is shown to be more effective than simple LRU or LFU.
Replacement Timing: Replacement can occur on-demand or be preplanned. Preplanned replacement may involve releasing multiple slots at once, especially when sectors that have been updated need to be written back to disk before replacement.
