2007年7月4日 星期三

User Mode Driver Framework

User Mode Driver Framework Development Concepts
  • allows an intermediate driver to load in user mode
  • cannot directly access hardware
  • some drivers will be more stable in user mode
  • reflector in kernel makes a user mode driver work as if it was a kernel mode driver
User Mode Driver Framework Architecture



The user mode driver framework is divided into two physical components.
  • the user mode driver reflector, which reside inside the device manager.
    • manages the user mode driver host processor.
    • forwards the requests that are issued by the device manager.
    • provides services for a user mode driver.
  • the user mode driver host, which is a user mode application that is launched and managed bye the user mode driver reflector.
    • it is used at the kernel's request to launch and to manage a user mode driver.
    • it is responsible for mounting the API of a volume in order to receive forwarded requests from the user mode driver reflector.
Registry
  • stores configuration information for applications, drivers, and the OS.
  • OS uses registry to locate and load device drivers.
  • Same basic setup as the desktop windows OS registry.
  • space is limited, so keep any new entries short.
Device Manager
  • manages devices and their interfaces.
  • decides which drivers to load.
  • uses registry to find drivers.
  • runs continuously.

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