Command Processing

a)When there is an error in the CDB, the IDD responds with a CHECK CONDITION status at the point when that command is fetched from the queue.

b)If the IDD is in the not ready state at the point when the queued command is fetched, it responds with a CHECK CONDITION status.

c)If a UNIT ATTENTION condition is generated before the queued command is fetched, a CHECK CONDITION status may be replied.

1.4.2Tagged queuing

Through the tagged queuing function, the IDD can receive multiple commands from the same INIT or from different INITs until the command queue is full. The number of commands that it is possible to receive by the IDD is 128 maximum, without relation to the INIT. When the IDD receives a new command, if the command queue is full, it responds to the new command with the QUEUE FULL status.

The IDD manages the command queue, but it is possible for the INIT to add or clear commands from the queue. When adding a command to the queue, it is possible for the INIT to specify the order in which commands should be executed or the command that should be executed next to the IDD.

If the disconnect right is not recognized in the IDENTIFY message of a tagged command, the IDD responds with a BUSY status.

Through the QUEUE TAG message, the INIT can attach a unique tag (ID) to each command. The INIT can set that command’s pointer correctly by the tag sent when the IDD reconnects. One INIT can issue multiple commands to the IDD only when the respective commands have unique tags.

If an ORDERED message is used, the IDD executes the other commands not included in the ORDERED message in the order in which they are received. All commands received with a SIMPLE message before commands are received with an ORDERED message are executed before those commands received with the ORDERED message. All commands with SIMPLE messages received after commands received with the ORDERED message are executed after the commands received with the ORDERED message.

Commands received with a HEAD OF QUEUE message are registered at the top of the queue for waiting execution. The IDD does not interrupt the current command execution and executes them after completion of current command execution. When commands with the HEAD OF QUEUE message are received continuously, the IDD first executes the command which was received last.

During the IDD executes or queues a tagged command, the same INIT must issue untagged commands except when the IDD is in the sense hold state.

The IDD handles a series of linked commands as if it were processing a single command and processes the series of commands by the tag received with the first command. A command with a HEAD OF QUEUE received before processing of a series of linked commands is completed is executed by the IDD after all the linked commands in the series have been executed.

The RESERVE, RELEASE and RESERVE EXTENDED commands should be issued together with an ORDERED message. If the HEAD OF QUEUE message is used with these commands, previously issued commands and reserved states may become redundant.

The TEST UNIT READY and INQUIRY commands do not influence the state of the IDD, so they can be issued together with a HEAD OF QUEUE message.

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Fujitsu MAP3147, MAP3367, MAS3735, MAP3735, MAS3367 specifications Tagged queuing
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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.

Similarly, the MAP3367 and MAS3367 models are geared towards both enterprise and mid-range server environments, providing a storage capacity of up to 300 GB as well. These drives also operate at a spindle speed of 15,000 RPM, offering swift access times that enhance overall system performance. The MAP3367 employs the Ultra 320 SCSI interface, allowing for significant bandwidth and ensuring data is transmitted efficiently.

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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