A host operating system (OS) can function as a task under a disk drive operating system. The host OS and the disk drive operating system can be run on a single processor. The processor is able to maintain the real-time response characteristics of a disk drive controller. A shared memory subsystem can be accessed by both operating systems. A disk drive storage device can access and respond to metadata about an underlying file system maintained by a host operating system (OS) to optimize data transfers between the disk drive and the host OS. The disk drive can identify the nature of read/write accesses, allowing it to prioritize and performance optimize the accesses. The disk drive can perform these functions without any changes to the block interface.