Abstract: A system and method for protecting shared system files enhances system stability by preventing system files shared by applications, such as DLL files, from being overwritten with invalid files during installation or update of applications or by user actions. A monitoring component monitors changes to the system files. When the monitoring component detects that a protected system file is being changed, it saves a copy of the original file and informs a file protection service of the change. The file protection service checks the modified file to determine whether it is valid. If the modified file is invalid, the system file is restored to its original contents using the copy saved by the monitoring component. Unauthorized importation of system files by application installers or update packages is prevented by requiring the use of a certificate issued by a party with proper authority.

Abstract: Method and apparatus for maintaining a queue structure having data nodes within a computer memory. The queue is maintained by the steps of maintaining a pool of available data nodes for use in maintaining the queue structure. Data is added to the queue structure by adding a nodes to the queue structure. Each data node includes a data portion, a link for addressing other data nodes in the queue structure, and an identifier. Data within the queue is accessed and then removed from the queue but the data nodes are preserved in memory by adding them to the pool of available data nodes. New data nodes are added to the queue by first checking the data pool, which in an exemplary embodiment is in the form of a stack, to determine if there are any nodes available in the pool before creating a new data node.