H is explained in the next paragraph. You now must invent some workloads. A simple workload assumes that each of these operations is equally likely to occur. A hot item is accessed frequently and a cold item is accessed infrequently. Thus, you decide to use a Zipf distribution to model this hot-cold workload .
Zipf distribution favors some values more than others.
To generate an operation in this workload, you will have to first make a random choice of one of the three operations, and then you will have to select a key using the Zipfian distribution. Further assume that you have a database with 1000 keys. You then realize that you might be able to illustrate some other really cool points if you were to try some alternative workloads. After all, you have the simulator all built. You decide to try a workload in which the insertions and deletions dominate the lookups.