We analyzed the UNIX 4.2BSD file system by recording activity in trace files and writing programs to analyze the traces. The trace analysis shows that the average file system bandwidth needed per user is low (a few hundred bytes per second). Most of the files accessed are short, are open a short time, and are accessed sequentially. Most new information is deleted or overwritten within a few minutes of its creation. We wrote a simulator that uses the traces to predict the performance of caches for disk blocks. The moderate-sized caches used in UNIX reduce disk traffic by about 50%, but larger caches (several megabytes) can achieve much greater reductions, eliminating 90% or more of all disk traffic. With those large caches, large block sizes (16 kbytes or more) result in the fewest disk accesses.
Cited By
Gottschlich J, Vachharajani M and Siek J An efficient software transactional memory using commit-time invalidation Proceedings of the 8th annual IEEE/ACM international symposium on Code generation and optimization, (101-110)- Lee L, Scheuermann P and Vingralek R (2000). File Assignment in Parallel I/O Systems with Minimal Variance of Service Time, IEEE Transactions on Computers, 49:2, (127-140), Online publication date: 1-Feb-2000.
- Kuenning G, Popek G and Reiher P An analysis of trace data for predictive file caching in mobile computing Proceedings of the USENIX Summer 1994 Technical Conference on USENIX Summer 1994 Technical Conference - Volume 1, (20-20)
- Zwaenepoel W (2019). Protocols for large data transfers over local networks, ACM SIGCOMM Computer Communication Review, 15:4, (22-32), Online publication date: 1-Sep-1985.
- Zwaenepoel W Protocols for large data transfers over local networks Proceedings of the ninth symposium on Data communications, (22-32)
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