(2)Alternate block allocation

Alternate data blocks are allocated in defective sector units for defective data blocks (= sectors) on the disk media by the IDD's internal defect management methods.

a.Spare sector area

Spare sectors for allocation as alternate blocks are secured in one or both of the following areas. When the INIT initializes the disk media, it can specify the spare sector area to be prepared on the disk drive and the size of that area. For details, see the description in Section 3.1.2 "Spare Area for Alternates" in the "Product Manual."

•Spare sectors within a cylinder

Spare sectors are secured in the final track of each cylinder. They are used as alternate blocks for defective sectors within the same cylinder.

•Alternate cylinders

This is an exclusive cylinder for allocation of alternate blocks. Alternate cylinders are secured only in the specified quantity in order from the topmost cylinder. Spare sectors in an alternate cylinder are used only in the case that the spare sectors within each cylinder are used up and alternate block allocation is not possible within the same cylinder.

b.Alternate block allocation methods

Alternate block allocation processing is performed using one of the following methods.

•Sector slip processing

This is a method of skipping defective sectors and writing the logical data blocks corresponding to those sectors in order in physically consecutive sectors. Sector slip processing is performed only within the same cylinder as the defective sectors and until all the spare sectors within that cylinder are used up.

•Alternate sector processing

This is a method of allocating logical data blocks corresponding to defective sectors to unused spare sectors within the same cylinder or to unused spare sectors in an alternate cylinder.

c.Alternate block allocation processing

Alternate block allocation processing is implemented by the FORMAT UNIT command, REASSIGN BLOCKS command or "Auto Alternate Block Allocation Processing." In sector slip processing, the defective sectors re excluded and logical data blocks are located in physically consecutive sectors, but when alternate block processing is performed, the affected logical data blocks are located in spare sectors which are not physically consecutive with the previous and following logical data blocks which are physically located on the disk. For details, see the description in Section 3.3.2 "Alternate Block Allocation" in the "Product Manual."

6 - 2

C141-E124-01EN

Page 288 Page 290
Page 289
Image 289
Fujitsu MAN3735 Spare sectors within a cylinder, Alternate cylinders, Sector slip processing, Alternate sector processing
Page 288 Page 290

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.
Top Page Image Contents