Abstract: Methods and apparatus that enhance the performance of computer file systems, and in particular the performance of read-only operations in such file systems. The invention can be implemented in a suite of computer program modules that together make up a performance enhancement product. The invention can transparently exist in an operating system after an initial setup is completed. The initial setup involves identifying what directories or files are to be monitored in order to intercept access requests for those files and to respond to those requests with enhanced performance. A system administrator can specify what directories or files are to be monitored. A high-performance index of monitored directories or files is maintained. When a monitored file is opened, a file identifier used, thereby bypassing the access of any directory meta data information. In one embodiment, access to monitored files is enhanced by pinning files in the data cache maintained by the file system cache manager.