Patent ID: 6799255
Filing Date: 2004-09-28
Classification: G06F,Y10S

Abstract:
A method of operating a storage controller for controlling access to data storage, the storage controller having a data port for connecting the storage controller into a data network for data transmission between the data storage and host processors in the data network, said method comprising:a) storing in memory information identifying a first host processor and, in association with the information identifying the first host processor, information identifying a first specification for the first host processor of a first subset of the data storage to which access by the first host processor is restricted to by said storage controller, and storing in the memory information identifying a second host processor and, in association with the information identifying the second host processor, a second specification for the second host processor of a second subset of the data storage to which access by the second host processor is restricted to by said storage controller, wherein the first host processor has access through the data port to the first subset of the data storage and the second host processor has access through the data port to the second subset of the data storage, the first subset of the data storage being different from the second subset of the data storage so that the first host processor is restricted from accessing through the data port at least some data storage in the second subset of the data storage and so that the second host processor is restricted from accessing through the data port at least some data storage in the first subset of the data storage; b) receiving at the data port a request for storage access from one of the first and second host processors, the request from said one of the host processors containing an identification of said one of the host processors and a specification of a portion of the data storage to access, and the storage controller responding to the request for storage access by: (i) decoding from the request for storage access the identification of said one of the host processors contained in the request for storage access; (ii) searching the memory to find the information identifying the host processor identified by the identification decoded from the request for storage access, and (iii) upon finding the information identifying the host processor identified by the identification decoded from the request for storage access, accessing in the memory the respective specification which is associated with the information identifying the host processor identified by the identification decoded from the request for storage access, in order to determine whether or not the portion of the data storage specified by the request for storage access is contained in the respective subset of the data storage specified by the respective specification which is associated with the information identifying the host processor identified by the identification decoded from the request for storage access, and (iv) accessing the specified portion of the data storage upon finding that the portion of the data storage specified by the request for storage access is contained in the respective subset of the data storage specified by the respective specification which is associated with the associated information identifying the host processor identified by the identification decoded from the request for storage access.