Abstract: Methods and structure for transferring additional parameters through a communication interface with limited parameter passing features. Features and aspects hereof provide for generating and transmitting multiple related commands from an initiator device to a target device where one or more initial commands provide additional parameters. The additional parameters are utilized in processing the last of the multiple commands to actually perform a desired data transfer. The initial commands and the data transfer command may all be associated by encoding of a common tag or sub-tag value in each command. The initial commands may be read/write commands having a zero data transfer length. The associated data transfer command may be a read/write command having a non-zero data transfer length. The initial commands each provide one or more additional parameters for processing the data transfer command in addition to the standard parameters that may be encoded in the data transfer command.

Abstract: Methods and structure for transferring administrative information through a communication interface. Features and aspects hereof provide for exchanging administrative information between an initiator device and a target device using read and write commands encoded with a reserved sub-tag value. In the context of a Serial Advanced Technology Attachment (SATA) system, a portion of a parameter (e.g., the LBA parameter) of a read or write command (a Native Command Queuing command) is defined to encode a sub-tag value. One or more sub-tag values are reserved to indicate that the corresponding read or write command is related to the exchange of administrative information rather than the reading or writing of data on a storage device. A parameter value encoded in the LBA field or data length field of the read or write command indicates administrative data to be returned to the initiator or to be updated within the target device.

Abstract: A disk drive is disclosed for executing a preemptive multitasking operating system comprising tasks of varying priority, including a disk task for processing disk commands by initiating seek operations and configuring parameters of a read/write channel, a host task for initiating disk commands in response to host commands received from a host computer, a background task for initiating disk commands to perform background operations including a defect scan of the disk, and an execution task for arbitrating the disk commands generated by the host task and the background task and for transmitting the arbitrated disk commands to the disk task.

Abstract: A method for managing data blocks in a cache buffer defining date block segments, and for automatically transferring data into and out of the cache buffer. A cache list comprises a plurality of entries each including information identifying a corresponding cache segment, and a set of consecutive data blocks stored in the cache segment. Providing cache status for a requested set of date blocks includes traversing the cache list to locate entries identifying the starting data block in the requested set, and consecutive data blocks successively following the starting data block without interruption, and identifying as a missing data block the first data block in said succession, including said starting data block, not identified in any entry. The missing data block is used to provide status: a full hit if the missing data block is not in the requested set; a miss if the missing data block is the starting data block in the requested set, or a partial hit otherwise.