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Fujitsu MAP3367, MAP3147, MAS3735 Command Queuing Function, If disconnect processing is impossible

Models: MAP3735 MAP3147 MAS3367 MAP3367 MAS3735

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1.4 Command Queuing Function

When a command is in the queued state, if a RESET condition occurs, or if the IDD receives a TARGET RESET message from any INIT, it clears all the commands in the queue. At this time, the IDD generates on UNIT ATTENTION condition for all the INITs.

When an ABORT message is sent from an INIT that has issued a command which is in the queue, if the correct LUN (0) is specified, only the command issued by that INIT is cleared and the other commands in the queue are not effected. If the LUN is not identified, an ABORT message which specifies an illegal LUN (1 to 7) does not effect the commands in the queue.

Untagged queuing exception processing (events and operations executed by the IDD) is shown below.

• If the TEST UNIT READY, REQUEST SENSE or INQUIRY command is received.

When one of these commands is received, if there is no link instruction in that command, the IDD executes that command immediately without queuing the command or executing disconnect processing. At this time, there is no effect on the commands from other INITs which are currently being executed, or on the commands in the queue.

If these commands contain link instructions, they are queued.

• If disconnect processing is impossible.

If disconnect processing is impossible because the INIT which issued the command does not meet the conditions for permitting a disconnect (see Section 1.3.3), or if the DISCONNECT message is rejected by the INIT even though it meets the conditions for permitting a disconnect, the IDD responds with a BUSY status without queuing the received command except the case described in item 1) in following Note during executing or queuing command already. If this is not the case, the received command is executed immediately.

• If the IDD is reserved

If the IDD has been reserved by an INIT using the RESERVE command and receives a TEST UNIT READY command after that, when that command conflicts with the reserved state, it responds with a RESERVATION CONFLICT status. Commands after that are queued, and the reserved state is checked when a command is fetched from the queue. Conflicts with the reserved state are explained in the description of the RESERVE command (Section 3.1.11).

Note:

Through the operation of the command queuing function, except for exceptions described on this page, the IDD does not respond to commands issued by the INIT with a BUSY status. This function is applied under the multi-initiator environment, and overhead for re-issuing commands caused by the BUSY status is unnecessary. Normally, the INIT does not have to be aware of the existence of a queuing function, but it is necessary to exercise caution in the following items when controlling input/output processing.

1)When a command is queued, the time from the queuing of the command to its actual execution will vary depending on the commands already in the queue, or on the content of the processing currently being executed. Particularly in cases where the FORMAT UNIT command and START/STOP UNIT command (Immed = 0), and data access commands which specify large processing block counts, are already queued or being executed, the newly queued command will be forced to wait a long time until it is executed.

2)In the following cases, a command may not be executed even after it has been queued.

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Fujitsu MAP3367, MAP3147, MAS3735 Command Queuing Function, If disconnect processing is impossible, If the IDD is reserved
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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.