Abstract: Broadly speaking, a method and an apparatus is provided for processing access commands directed to a striped configuration of disks. More specifically, the method and apparatus determines a physical block address corresponding to a logical address in a redundant array of independent disks level 0 (RAID 0) system. Bit-level operations are incorporated to determine a disk in the RAID 0 system and a block number on the disk that corresponds to a particular logical address. Since the bit-level operations replace traditionally required division and modulo operations, the method and apparatus provides for more efficient processing of access commands directed to the RAID 0 system.

Abstract: Broadly speaking a method and an apparatus is provided for distributing commands to a digital data storage system. More specifically, the method and apparatus distributes read commands to a mirrored pair of disk drives in a substantially balanced manner. A read command having an associated starting address is received from an operating system. An address range is updated based on the starting address associated with the read command. A determination is made as to a portion of the address range containing the starting address associated with the read command. The read command is directed to be performed using a disk drive associated with the portion of the address range determined to contain the starting address.

Abstract: Methods and an apparatus for enabling the interoperability of a RAID implementation between different host systems by compacting the meta data so the meta data is accessible by the different systems are provided. In one embodiment, a method for enabling interoperability of a RAID implementation between different host systems is provided. The method initiates with meta data being identified for a RAID implementation. Next, the meta data of the RAID implementation is stored. Then, the RAID implementation is transferred from a first host system to a second host system. Next, the meta data for each disk of the RAID implementation is accessed in response to the start-up of the second host system. The compact meta data allows for a simplified migration process also. Computer readable media and a RAID system are also provided.

Abstract: Methods and a system for combining commands for data transfers between a drive and memory. One exemplary method includes receiving multiple read or write commands in a queue. Then, a first command of the multiple read or write commands is processed. Next, the multiple read or write commands are combined. The combination includes identifying like commands each being associated with a file stored on a drive and ascertaining which of the files associated with the like commands are contiguous. Then, a combined command is created, where the combined command consolidates the identified like commands being associated with contiguous files. Next, the combined command is issued to the drive.

Abstract: Methods and an apparatus for RAID load balancing are provided. One exemplary method includes establishing first and second counters where the first counter is associated with a first drive and the second counter is associated with a second drive. Next, a command is received form an operating system. Then, it is determined if the received command is a read command. If the received command is a read command, then the counters are examined to determine which of the counters is a lower value counter or if the counters are of equal value. Next, a drive associated with the lower value counter is selected or if the counters are of equal value a first drive is selected. The lower value counter is then incremented. Then, the read command is directed to the drive associated with the lower value counter or the first drive if the counters are of equal value.