The Use of Air Power in the Balkans during the 1990s Air Power, Coercion and Crisis Management.

Cache space is managed using LRU, but the implicit assumption is that the cache is usually large enough to hold the set of files currently in use. If a file is created and the capability lost, the file can never be accessed but will remain forever. To prevent this situation, timeouts are used. An uncommitted file that has not been accessed in 10 minutes is simply deleted and its table entry freed. If the entry is subsequently reused for another file, but the old capability is presented 15 minutes later, the Check field will detect the fact that the file has changed and the operation on the old file will be rejected. This approach is acceptable because files normally exist in the uncommitted state for only a few seconds. For committed files, a less draconian method is used. Associated with every file (in the file table entry) is a counter, initialized to MAX_LIFETIME. Periodically, a daemon does an RPC with the bullet server, asking it to perform the standard age operation (see Fig. 7-5). This operation causes the bullet server to run through the file table, decrementing each counter by 1 ...»