Command Processing

(6)INTERMEDIATE CONDITION MET Status

This status is reported when it is possible to secure the cache memory area necessary to read all the logical data blocks specified in a PRE-FETCH command which specifies a link (in the case of “Immed = 1”), or when reading of all the specified logical data blocks is completed (in the case of “Immed = 0”).

The IDD does not support the PRE-FETCH command. Therefore, this status is not reported.

(7)RESERVATION CONFLICT status

This status indicates that the IDD is reserved by another INIT, and that use is impossible until the reserved status is canceled. Normally, an INIT which receives this status reissues the original command after waiting an appropriate period of time.

(8)COMMAND TERMINATED status

This status is reported when the IDD has completed the executing input/output operation when it received a TERMINATE I/O PROCESS message from the INIT.

(9)QUEUE FULL status

This status is reported if the IDD cannot register a received tagged command in the command queue because there is no empty space in the command queue.

1.3Outline of Command Processing

1.3.1Single commands

Following shows single command processing examples which are the most basic operations on the SCSI bus. Furthermore, if disconnect processing is permitted, it may be accompanied by disconnect/reconnect processing during the command execution, depending on the type of command, but this operation is omitted in the following explanation. The disconnect function is described in Section 1.3.3.

1)The INIT sets the initial values for the command in the command pointer, data pointer and status pointer.

2)The INIT selects the TARG in the SELECTION phase after obtaining the SCSI bus usage in the ARBITRATION phase. After the SELECTION phase is ended, the SCSI bus control is entrusted to the TARG.

3)If the ATTENTION condition exists when the TARG responds to the SELECTION phase, the TARG executes the MESSAGE OUT phase. Normally, the INIT sends the IDENTIFY message as the initial message and specifies the device (LUN) that is the object of the operation.

4)The TARG executes the COMMAND phase and receives the CDB from the INIT. The TARG judges the length of the CDB by the group code in the first byte of the CDB and requests transfer of the necessary number of bytes.

5)The TARG investigates the contents of the command and executes the requested operation. In the case of commands for which data transfer on the SCSI bus is necessary, the DATA IN or the DATA OUT phase is executed.

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Fujitsu MAP3147, MAP3367, MAS3735, MAP3735, MAS3367 specifications Outline of Command Processing Single commands
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MAP3735, MAP3147, MAS3367, MAP3367, MAS3735 specifications

Fujitsu, a renowned leader in technology and innovation, has developed a variety of reliable hard disk drives (HDDs) that cater to a wide range of data storage needs. Among these, the MAS3735, MAP3367, MAS3367, MAP3147, and MAP3735 series stand out for their advanced features and exceptional performance.

The MAS3735 is a high-capacity enterprise-class drive that boasts a storage capacity of up to 300 GB. Its 10,000 RPM spindle speed ensures rapid data retrieval and efficient performance, making it ideal for data-intensive applications. It utilizes a Serial Attach SCSI (SAS) interface, which allows for improved data transfer rates and increased reliability compared to traditional SATA drives. The drive is designed with advanced technologies such as error recovery and data integrity features, ensuring the safety and security of critical data.

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On the other hand, both MAP3147 and MAP3735 models provide versatile solutions for various applications, supporting capacities from 36 GB to 147 GB. The MAP3147, with its 10,000 RPM speed, is optimized for workloads requiring quick access and high throughput, making it suitable for transactional systems and enterprise applications. The MAP3735, while offering comparable capacity, emphasizes exceptional reliability and durability, which is crucial for environments that involve heavy data loads.

All these Fujitsu HDDs are characterized by their robust construction, reliability, and efficiency. They are built to withstand heavy workloads and are equipped with features like advanced thermal management and acoustic noise reduction, ensuring they operate effectively in data center environments.

In conclusion, Fujitsu's MAS3735, MAP3367, MAS3367, MAP3147, and MAP3735 series HDDs are designed for high performance and reliability, catering to both enterprise and mid-range environments. Their advanced features make them a strong choice for businesses looking to enhance their storage solutions while maintaining data integrity and system performance.
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