This section summarizes kernel-mode support routines that NT drivers can call, according to the following general categories:
·Support routines that drivers can call while processing IRPs in Section 1.2.1
·Support routines that higher-level NT drivers can call to allocate and set up IRPs for requests to lower drivers in Section 1.2.2
·Support routines that drivers can call to use file objects in Section 1.2.3