I/O Caching 101

Data items from secondary storage are cached in memory for faster access time.

HASH(object)

free/inactive list tail

hash

function

free/inactive

list head

hash

bucket

array

hash

chains

methods:

object = get(tag)

Locate object if in the cache, else find

a free slot and bring it into the cache.

release(object)

Release cached object so its slot may

be reused for some other object.

I/O cache: a hash table with an integrated free/inactive list (i.e., an ordered list of eviction candidates).