ISAM

What
ISAM is a static structure treed based index

How

 * 1) Allocate leaf/data pages sequentially
 * 2) Sort the records by search key
 * 3) Allocate index pages
 * 4) Allocate overflow pages

Details

 * ISAM is a static tree structure because all inserts and deletes only modify the leaf nodes

Insertion
Data will occupy any available slot, but in the case that the page is all full, ISAM will allocate a new overflow page for the data we want to insert

Deletion
When an overflow page becomes empty, ISAM deallocates it