Alice has 2 types of memory, one is type A , it is very fast buy small, it takes 5 mc to read an object and is 10GB . the other memory is type Z. it is 1TB in size and can store . Reading an object takes 200ms Alice is going to build a system where she keeps objects in both memories. She has 2048 objects all the same size. Which use up all of her type Z memory. She wants to anayle different ways she can use the 2 memories.
If alice randomly fill the type A memory and never changes it, what is her expected time to read 10 objects?
Alice now runs a workload where 20 obj per minutes. 50% of the objects she reads in are objects shes has seen in the past 30 sec. the other 50% are randomly take from the full 2048. Using the same naive strategy as before what is her expected average time to read an object?
Now Alice decides that every time she reads an object she will add it to memory A, when she needs to remove something she will remove the oldest object in the memory , what is her new BEST case AVERAGE runtime ? (continuation of q2)
WORST case AVERAGE runtime for 1 obj?