1. In a computing environment having an operating system and a file system, wherein the operating system includes a component that receives file system-related function calls and provides corresponding I/O request data directed to the file system, a system comprising: a plurality of filter drivers; and a filter manager that: a) registers each of the filter drivers; b) arranges the filter drivers in at least one pre-callback order, each pre-callback order corresponding to a set of one or more of the filter drivers; c) receives the request data; d) calls at least one of the filter drivers based on a selected pre-callback order, including providing callback data based on the request to each filter driver called; e) receives a status from each filter driver called; and f) passes an I/O request towards the file system including data corresponding to the callback data.