5.3 Disk Drive Error Recovery Processing

If error correction is permitted but immediate correction is not permitted (DCR = 0, EER = 0), reading of data as in item (2) is retried up to the number of times specified in the other MODE SELECT parameters ("Number of Retries during Read" or "Number of Retries during Write").

If error correction is prohibited (DCR = 1, EER = 0), reading of data as in item (2) is retried up to the number of times specified in "Number of Retries during Read" or "Number of Retries during Write."

If the error cannot be recovered from even when this retry processing is executed, the IDD terminates the command that is currently being executed with a CHECK CONDITION status. The sense key in the sense data at this time is "MEDIUM ERROR [=3]" and the sense code indicates "Unrecovered read error [=11-00]."

(4)Other internal IDD errors

If an irrecoverable error other than those in items (1) to (3) above is detected internally in the IDD, the IDD terminates the command that is currently being executed with a CHECK CONDITION status. The sense key in the sense data at this time is "HARDWARE ERROR [=4]."

5.3.2Auto alternate block allocation processing

The IDD is equipped with a function which automatically executes alternate block allocation processing for defective data blocks detected during execution of the READ and READ EXTENDED commands.

(1)Auto alternate block allocation processing during a read operation

This function is enabled by specifying "1" in the ARRE flag in the MODE SELECT parameters. Furthermore, this function is applicable to the following commands only.

•READ command

•READ EXTENDED command

When this function is permitted, if, during read processing to the data area, an error which is an object of retry processing is detected, and which it is impossible to recover from even when reading is retried (see Section 5.3.1 (2)) the number of times specified in the "Number of Retries during Read" field in the MODE SELECT parameters, the IDD allocates an alternate block for that data block and executes copying of the alternate block to the data area. Alternate block allocation processing is the same as processing with the REASSIGN BLOCKS command. Furthermore, recovered data copied to the alternate block are data which are read out, skipping the ID area, if there is an ID area, or they are data which have been corrected through the ECC.

This function is applied twice only during execution of one command. Alternate block allocation processing and copying are executed for the first and second defective data block to be detected during execution of a command, but if a third defective data block is detected, the command that is being executed at that point is terminated with an error. However, by the INIT's reissuing the same command, auto alternate block allocation is applied sequentially and error recovery can be attempted.

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Fujitsu MAS3735, MAP3367, MAP3147, MAP3735 Disk Drive Error Recovery Processing, Auto alternate block allocation processing
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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.
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