Data Format

(3)Automatic alternate block allocation

• Automatic alternate block allocation at read operation

If the ARRE flag in the MODE SELECT parameter permits the automatic alternate block allocation, the IDD automatically executes the alternate block allocation and data duplication on the defective data block detected during the READ or READ EXTENDED command. This allocation method is the same as with the REASSIGN BLOCKS command (alternate sector treatment).

•Automatic alternate block allocation at write operation

If AWRE flag in the MODE SELECT parameter permits the automatic alternate block allocation, the IDD executes the automatic alternate processing during WRITE command processing as described below:

1)Commands to be applied

-WRITE

-WRITE EXTEND

-WRITE at executing WRITE AND VERIFY

2)Application requirements

When any of the above commands is issued to LBA registered in the uncorrectable error log of the READ command (LBA log of uncorrectable error while the READ command is executed), the AWRE processing is applied.

3)AWRE processing

The following processings are performed when the LBA matches the one in the uncorrectable error log:

a)Primary media check

-Creates an uncorrectable error pattern (invalid LBA pattern) in the position of the error LBA, repeats the primary media check up to three times. If the error still occurs after the check repeated three times, it is judged to be defective. Then, it performs the alternate processing.

b)Alternate processing

-Alternate media check

Writes the data that causes an unrecoverable error into the alternate block, and performs the media check.

(If the alternate block is a defective sector, the block is registered to the G list, another alternate block is allocated.)

c)SA and defect map update processing (on alternate side)

When an error occurs in the alternate processing, this WRITE command terminates with error.

When the alternate processing normally terminates, the WRITE command is executed.

Depending on the alternate processing result, one of the following sense codes is returned:

Alternate processing is succeeded: 01-OC-01

Alternate medium is defective:

03-OC-01

Fatal error (SA write retry out):

03-OC-02

3-14

C141-E163

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Fujitsu MAP3147FC, MAP3735FC manual Write Write Extend
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MAP3735FC, MAP3147FC specifications

Fujitsu has been a prominent player in the hard disk drive market, with its MAP3147FC and MAP3735FC models standing out in terms of performance and reliability. These drives are engineered to meet the growing demands of enterprise applications, providing robust solutions for data storage in critical environments.

The Fujitsu MAP3147FC, with a capacity of 147 GB, is optimized for high-speed data access and storage efficiency. This 3.5-inch SCSI drive operates at a rotational speed of 15,000 RPM, ensuring rapid data retrieval and minimized latency, making it ideal for applications requiring quick transaction processing. It features a 4 Gbps Fibre Channel interface, which enhances connectivity and system integration, promoting seamless communication between devices in storage area networks.

On the other hand, the MAP3735FC model offers a higher capacity of 300 GB. It shares similar specifications with its counterpart, including the 15,000 RPM speed, which guarantees top-notch performance for mission-critical applications. The MAP3735FC, like the MAP3147FC, incorporates advanced technologies such as Command Queuing, which optimizes the execution of multiple read and write commands in a queue. This feature is particularly beneficial in environments with high I/O demands, improving overall system throughput and efficiency.

Both drives utilize sophisticated error correction techniques, ensuring data integrity and reliability. They are equipped with features like S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology), which continuously monitors the health of the drives and helps predict potential failures, allowing for proactive maintenance and data protection.

In terms of physical characteristics, both models are designed to withstand the rigors of continuous operation. They are built with a rugged casing to protect against vibration and shock, making them suitable for use in enterprise-level servers and storage systems. Their design also allows for efficient heat dissipation, which is critical for maintaining optimal performance during extended use.

In summary, Fujitsu's MAP3147FC and MAP3735FC hard drives embody a combination of high speed, reliability, and advanced features tailored for enterprise environments. Their robust performance, large storage capacities, and reliable error correction technologies make them an excellent choice for businesses looking to optimize their data storage solutions and ensure seamless operation in demanding applications. With Fujitsu's commitment to quality and innovation, these models continue to meet the evolving needs of the data storage industry.
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