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Fujitsu MAN3735, MAN3367, MAN3184 specifications Look-Ahead Cache Feature, Caching operation

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

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2.2Look-Ahead Cache Feature

In order to use the data buffer more effectively and improve the disk drive's effective access speed, the IDD is equipped with a simple cache feature called a "Look-Ahead Cache Feature." The Look- Ahead cache feature is an effective, simple cache function for an INIT which reads data block groups on the disk media sequentially using multiple commands.

2.2.1Caching operation

When the IDD is executing a READ command or a READ EXTENDED command, it reads the requested data from the disk media and transfers it to the INIT while at the same time reading (looking ahead at) data blocks which are subsequent to the last logical data block specified in that command to the data buffer. Then, when a READ command or READ EXTENDED command issued later specifies any of those Look-Ahead data blocks, the IDD transfers those data directly to the INIT from the data buffer without accessing the disk media. In this way, when continuous logical data block groups are read sequentially by multiple commands, mechanical access operations can be eliminated and effective access time greatly reduced.

An INIT can prohibit the operation of this Look-Ahead cache feature by setting the caching parameter described in section 2.2.2.

(1)Caching object commands

Commands which execute caching operations are the commands shown below:

ξREAD

ξREAD EXTENDED

If all the data block groups which are objects of the processing specified in these commands, or a portion of the data blocks, including the top logical data block specified in these commands are relevant data (See item (2)) for caching in the data buffer (if they hit), when the IDD receives a command and performs disconnect processing, it immediately reconnects and sends the data on the data buffer which can be transferred to the INIT. The caching operation can be disabled by the FUA bit of the READ EXTENDED command. If "1" is specified in the FUA bit, the IDD reads data from the disk media.

On the other hand, if the top logical data block specified in a command is not relevant data for caching in the data buffer (if they miss), reading of data is performed from the disk media using the old cache segment.

(2)Data which are objects of caching

Data which exist in the data buffer and which are objects of caching in item (1) (data which are not accessed from the disk media but are transferred to the INIT from the data buffer) are as described below.

a)Data read by a READ or a READ EXTENDED command and which have been read to the data buffer by Look-Ahead are data which are objects of caching. Depending on the timing for halting Look-Ahead, it is possible that data read by the READ command will be overwritten by Look-Ahead.

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Fujitsu MAN3184, MAN3367, MAN3735 SERIES DISK DRIVES specifications Look-Ahead Cache Feature, Caching operation
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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.