Methods and apparatus for updating file systems

摘要

A file system in a computer is disclosed. The file system is configured to service file access requests between an application program and a first data storage subsystem. The file system includes a first persistent module coupled to receive a first file access request. The first persistent module is associated with the first data storage subsystem. The first file access request pertains to the first data storage subsystem. The file system includes a first transparently unloadable module coupled to the first persistent module to service the first file access request. The first transparently unloadable module is configured to be dynamically unloadable from the computer, wherein the first persistent module includes a blocking arrangement for blocking the first file access request at the first persistent module to allow the first transparently unloadable module to be unloaded without causing an error in the application program. The first persistent module includes memory for storing data necessary to allow the first file access request to be serviced in a manner substantially transparent to the application program after a substitute transparently unloadable module associated with the first data storage subsystem is loaded in place of the first transparently unloadable module.