Search Sequence in the ICM Server Cache 
When the ICM Server Cache (ISC) is being searched for a requested object, the following steps are taken, in this order:
● First the UFO List is checked to see if this request has already been rejected once by the system and is to be rejected again.
●
The
application then looks in the Main
Memory of the ICM server cache (Memory Cache), and 
icm/HTTP/server_cache_<xx>/memory_size_MB
establishes the size of the part of the ISC in main memory.
●
The
application then looks for the object in the File on the hard disk that the ISC is using
(Disk Cache). The
parameter icm/HTTP/server_cache_<xx>/size_MB
establishes the total size of the ISC (a part of which is instantly accessible
as it is stored in main
memory).
See: