The metric reports on the ratio of requests serviced from the cache. It is the ratio of bytes serviced from the cache. The cache hit rate is higher than the cache byte hit rate because requests resulting in cache hits tend to be smaller files. Note that requests mapping to files not found are excluded from these calculations. If the cache size is zero bytes then no files are cached.
All requests are cache misses.
Here is a sample run with a cache size of 100000 bytes. Test runs with a non-zero fixed size cache cause the cache replacement policy to be exercised. Adding in the clock replacement policy to handle cache sizes specified on the command line is worth 24 of the 30 points. For the remaining points on the project, you need to implement one or more additional cache replacement policies. In implementing these policies, you may need to change or add to the information stored for each cached file.