Patent ID: 8448239

Claim:
A storage controller comprising: a partitioning mechanism to partition a storage device into partitions having one of three or more levels of security, wherein the partitioning mechanism comprises register sets to define a range of locations within the storage device for each security level, and wherein the partitioning mechanism is coupled to be responsive to a plurality of signal lines provided on a bus by a bus master to indicate a security level in which the bus master is operating, and to allow execution of instructions in a partition only when the bus master is operating at a security level appropriate for the partition; and a command pointer register to point to a chain of commands, the command pointer register having a plurality of bits to signify the security level of a first command of the chain of commands, and wherein each command of the chain of commands is part of a node in the chain of commands, said each node including a command, an address field to point to a next command, and a storage area to indicate a security level of the next command.