A new cooperative caching mechanism, PACA, along with a caching algorithm, LRU-Interleaved, and an aggressive prefetching algorithm, Full-File-On-Open, are presented. The caching algorithm is especially targeted to parallel machines running a microkernel-based operating system. It avoids the cache coherence problem with no loss in performance. Comparing our algorithm with another cooperative cache one (N-Chance Forwarding), in the above environment, better results have been obtained by LRU-Interleaved. We also evaluate an aggressive prefetching algorithm that highly increases read performance taking advantage of the huge caches cooperative caching offers.