Abstract: The persistent binding of STP SAS addresses to SATA devices is disclosed so that SATA devices can be moved to different insertion points (ports) within a SAS expander and still properly receive I/O requests. When a SATA device is inserted into the SAS expander, it is interrogated to obtain information about the attached device. This information may be combined using a hashing function to obtain a unique ID for the SATA device. A table can be used to assign a STP SAS address to the Phy connected to the device based in the unique ID. In this manner, the same STP SAS address will be assigned to the Phy connected to a particular SATA device, regardless of where the device is connected to the SAS expander.

Abstract: A system for enabling SATA drives to be utilized in FC SANs is disclosed. To send data to a SATA drive over a FC SAN, a host sends SCSI commands encapsulated in FC frames over a standard FC link to a Fibre Channel Attached SATA Tunneling (FAST) RAID controller, where the SCSI commands are de-encapsulated from the FC frames and translated to SATA FISs. The SATA FISs are thereafter encapsulated into FC frames. The IOC that performs these functions is referred to as a FAST IOC. The SATA-encapsulated FC frames are sent to multiple disk drive enclosures over another standard FC link. The FC frames are de-encapsulated by FAST switches in disk drive enclosures to retrieve the SATA FISs, and the SATA FISs are sent to the SATA drives over a SATA connection.

Abstract: The persistent binding of STP SAS addresses to SATA devices is disclosed so that SATA devices can be moved to different insertion points (ports) within a SAS expander and still properly receive I/O requests. When a SATA device is inserted into the SAS expander, it is interrogated to obtain information about the attached device. This information may be combined using a hashing function to obtain a unique ID for the SATA device. A table can be used to assign a STP SAS address to the Phy connected to the device based in the unique ID. In this manner, the same STP SAS address will be assigned to the Phy connected to a particular SATA device, regardless of where the device is connected to the SAS expander.

Abstract: A prerequisite-based scheduler is disclosed which takes into account system resource prerequisites for execution. Tasks are only scheduled when they can successfully run to completion and therefore a task, once dispatched, is guaranteed not to become blocked. In a prerequisite table, tasks are identified horizontally, and resources needed for the tasks are identified vertically. At the bottom of the table is the system state, which represents the current state of all resources in the system. If a Boolean AND operation is applied to the task prerequisite row and the system state, and if the result is the same as the prerequisite row, then the task is dispatchable. In one embodiment of the present invention, the prerequisite based scheduler (dispatcher) walks through the prerequisite table from top to bottom until a task is found whose prerequisites are satisfied by the system state. Once found, this task is dispatched.

Abstract: A method for managing read and write data congestion in a system for executing write and read data commands and having a buffer pool of blocks for temporarily storing read and write data is disclosed. Management of the buffer pool and the initiation of read and write commands ensures that free blocks are available to temporarily store read data arriving at a host bus adapter (HBA). If the currently available blocks would be substantially consumed by the total outstanding inbound read data requested, no more write data commands will be initiated. As inbound read data is received into the buffer pool and subsequently transferred out of the buffer pool to the initiator device, the blocks in the buffer pool are freed up. When the read data transfer is completed and sufficient buffer resources have been freed up, read and write data commands may resume.

Abstract: A method for managing read and write data congestion in a system for executing write and read data commands and having a buffer pool of blocks for temporarily storing read and write data is disclosed. Management of the buffer pool and the initiation of read and write commands ensures that free blocks are available to temporarily store read data arriving at a host bus adapter (HBA). If the currently available blocks would be substantially consumed by the total outstanding inbound read data requested, no more write data commands will be initiated. As inbound read data is received into the buffer pool and subsequently transferred out of the buffer pool to the initiator device, the blocks in the buffer pool are freed up. When the read data transfer is completed and sufficient buffer resources have been freed up, read and write data commands may resume.