[echelon]

The hand is a pointer on the queue to the current cache item being inspected. The cache miss eviction behavior depends on if the pointed to element is marked as visited.

If you're familiar with LRU/LFU, ring buffers (though this isn't such), and data structures this will probably make a lot more sense.

A rigorous course in data structures is fantastic for any engineer. Everything is data structures and algorithms at the end of the day.