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Fujitsu MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES Command Queuing Function, Untagged queuing

Models: MAN3735 MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES MAN3367 MAN3184

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1.4Command Queuing Function

The IDD equips a command queuing function. Through queuing of commands, the IDD can receive multiple commands in advance and execute them.

There are two methods used in the queuing function, tagged and untagged. In tagged queuing, the IDD can receive multiple commands from each INIT. In untagged queuing, the IDD can receive a single command from each INIT.

Both queuing methods are possible for the IDD, but an INIT can use only one queuing method at a time. However, if another INIT selects a different method, the IDD controls both methods of command queuing.

1.4.1Untagged queuing

Using untagged queuing, the IDD can receive a command from an INIT while it is executing processing of a command from another INIT. The IDD can receive one command at a time from each INIT. It is the role of the INIT to confirm that only one command is issued every time.

When the IDD receives a new command from an INIT, if it is processing another command from a different INIT, or if it is currently executing its initial self-diagnosis, that command is queued in the command queue. In this case, the IDD executes disconnect processing after command queuing processing is completed.

After the IDD finishes executing the current processing command, if there is a command in the queue, it fetches that command and executes it. If there are multiple commands in the queue, they are fetched and executed in the order in which they were received.

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.

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Fujitsu MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES specifications Command Queuing Function, Untagged queuing
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MAN3735, MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES, MAN3367, MAN3184 specifications

Fujitsu's MAN3184, MAN3367, and MAN3735 series disk drives represent a significant advancement in storage technology, catering to the needs of businesses seeking reliability, performance, and high capacity. These drives are designed for enterprise environments, providing exceptional data integrity and speed essential for effective data management.

The MAN3184 series is renowned for its high rotational speed of 10,000 RPM, which significantly enhances data access times. With a capacity of up to 18.4 GB, these drives are suitable for applications requiring quick read and write operations. The series employs an improved read/write head technology, which reduces latency and increases overall performance. This technology is complemented by advanced error correction mechanisms, ensuring the reliability necessary for critical data applications.

Transitioning to the MAN3367 series, these drives offer increased storage capacity and improved performance metrics. With capacities reaching up to 36.7 GB, they cater to growing data demands in modern enterprises. They also feature a 10,000 RPM spindle speed, ensuring that the drives can handle intensive workloads with ease. The MAN3367 drives include SCSI interface support, making them versatile and easy to integrate into various systems. The inclusion of intelligent caching algorithms allows for faster data retrieval, while built-in thermal management features ensure optimal performance, even under heavy usage.

The MAN3735 series takes performance up another notch, boasting higher capacities of up to 73.5 GB. These drives are particularly suited for environments that require high reliability and availability. The series utilizes a state-of-the-art SCSI Ultra160 interface, which maximizes data transfer rates, ultimately enhancing overall system efficiency. Additionally, the MAN3735 series employs advanced data protection technologies, including power loss protection and predictive failure analysis, which proactively minimizes potential downtime.

All these series of Fujitsu disk drives are built with a focus on durability and sustained performance. They are designed to operate seamlessly in high-demand environments, ensuring that organizations can rely on them for critical applications. Their compact design and energy-efficient operation make them an ideal choice for modern data centers looking to optimize space and reduce power consumption.

In summary, Fujitsu's MAN3184, MAN3367, and MAN3735 series disk drives deliver a blend of high capacity, performance, and reliability. These drives incorporate advanced technologies that address the evolving needs of enterprise storage solutions, making them a valuable asset for any organization aiming to enhance their data management capabilities.