TCP_HIT
A valid copy of the requested object was in the cache.

TCP_MEM_HIT
A valid copy of the requested object was in the cache, AND it was in memory so it did not have to be read from disk.

TCP_NEGATIVE_HIT
The request was for a negatively-cached object. Negative-caching refers to caching certain types of errors, such as "404 Not Found." The amount of time these errors are cached is