Patent ID: 6125403
Filing Date: 2000-09-26
Classification: G06F

Abstract:
A method encoded in the form of binary program instructions for implementing a caching virtual device driver responsive to file I/O requests within a Microsoft Windows operating system, said operating system being provided with a virtual device driver (VxD) identified as the Installable File System Manager (IFSMGR), said method implemented on a local node computer system of a networked data processing system having at least one server computer system, said local node having a central processing unit (CPU), random access memory, a local data bus, and at least one local mass storage device on which data can be alterably stored, said server system having at least one mass storage device on which data can be alterably stored, said method comprising the steps of:providing for establishing a hook to the IFSMGR VxD at boot time initialization of the Windows operating system;providing for receiving a call from the IFSMGR VxD whenever the local node system processes a file I/O request;providing for assuming control of the request determining whether or not each request involves data on a mass storage device that has been configured by the user for caching;providing for returning control of the request to the IFSMGR VxD if a request does not involve data on a mass storage device that has not been configured for caching;if a request does involve data on a mass storage device that has been configured for caching, then providing for determining whether or not data which satisfies the request resides within an established cache at the local node;if data which satisfies the request resides within the established cache, then providing for supplying that data to the local data bus, and returning control of the request to the IFSMGR VxD; andif no data which satisfies the request resides within the established cache, then providing for retrieving a block of data, which includes the data which satisfies the request, from the server system's mass-storage device, storing the retrieved block in the cache, and supplying the data which satisfies the request to the local data bus, and returning control of the request to the IFSMGR VxD.