Temporary computer file system implementing using anonymous storage

Abstract

A devtmp device driver provides the functionality of temporary files by representing a virtual device and including the virtual device among several devices within which a file system can store files. Rather than storing data in and retrieving data from a physical device, the devtmp device driver stores data in and retrieves data from anonymous storage through a swap file system which manages anonymous storage for a virtual memory system. A file system uses the devtmp device driver in the same manner the file system uses conventional device drivers which store data in and retrieve data from secondary storage devices. Since the devtmp device driver represents a virtual device whose data are stored in anonymous storage managed by the swap file system, the total amount of storage available for storing data of temporary files is shared among the various components of a computer process to successfully satisfy various needs of various computer processes. Temporary files can be accessed through a main file system, e.g., the UNIX file system, using a delayed-write-mode. In the delayed-write mode, the file system does not write metadata of a device to secondary storage and writes substantive data of files stored on the device only when insufficient primary storage is available to store the substantive data. Accordingly, temporary files are stored in primary storage so long as primary storage is available for such temporary files and are stored in, or moved to, secondary storage when primary storage is unavailable.