Abstract: A method for implementing security management in a storage area network by controlling access to network resources. Initially, a resource provider communicates with potential resource users, such as host computers, servers, and workstations, to allow the users to discover the resources available on the storage area network. Resource users that have not previously logged in to a particular resource supply identification information to the resource provider, which places the information in a ‘not yet approved entity’ table. The ‘not yet approved entity’ table is made available to a management station. An administrator, using the management station, then determines whether to authorize use of resources. If access to the requested resource is allowed, the resource user identification information is stored in an ‘approved entity’ table. A login is then allowed by the resource user to the selected resource.

Abstract: A system for generating a virtual point-in-time copy of a selected subset (e.g., a selected volume or logical unit) of a storage system. The present system operates by using a bitmap in storage system controller cache memory to indicate blocks of memory in the selected volume that have been overwritten since the snapshot was initiated. When a write to the selected volume is requested, the cache bitmap is checked to determine whether the original data (in the area to be overwritten) has already been copied from the selected volume to a temporary volume. If the original data was previously copied, then the write proceeds to the selected volume. If, however, the original data would be overwritten by the presently requested write operation, then an area containing the original data is copied from the selected volume to a temporary volume. Reads from the temporary volume first check the bitmap to determine if the requested data has already been copied from the selected volume to the temporary volume.