Sense Data Error Recovery Methods

5.3Disk Drive Error Recovery Processing

This section explains concerning error recovery processing methods and procedures executed by the IDD for each type of disk drive related error. The INIT can control the error recovery processing methods executed by the IDD using the MODE SELECT parameters.

5.3.1Error states and retry processing procedures

(1)Seek error

Mechanical malfunctions of the disk drive during a seek operation and failure of serial addresses detected during verification of the ID area to match are included in this error.

When a seek error occurs, the IDD first executes rezero seek, then tries repositioning at the target cylinder and restarts the original processing. If the error is not recovered from, retry processing (rezero seek and repositioning) is performed up to the number of times specified in "Number of Retries during Seek Error" in the MODE SELECT parameters.

If the error cannot be recovered from even when retry processing is executed the specified number of times, the IDD terminates the command which is currently being executed with a CHECK CONDITION status. The sense key in the sense data at this time is "HARDWARE ERROR [=4]" and the sense code indicates "Mechanical positioning error [=15-01]" or "Positioning error detected by read of medium [=15-02]."

(2)Read error in uncorrectable data

This error is a failure to detect the Sync Byte pattern during reading of data or an ECC error for which correction processing is impossible. If this error is detected, the IDD, after waiting one revolution of the disk media, tries reading again. When the error is not recovered from, reading is retried repeatedly the number of times specified in the MODE SELECT parameter ("Number of Retries during Read" or "Number of Retries during Write").

In cases where correction is possible during execution of retry processing, the processing procedure is according to "Correctable Data Read Error" in item (3). If errors cannot be recovered from even after retry is executed the specified number of times, 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 "Sync byte not found for data field [=13-00]" or "Unrecovered read error [=11-01]."

In this error retry processing, rereading accompanied by head offset processing is performed.

(3)Correctable data read error

This error is a correctable ECC error when data are being read. Processing methods when this error is detected differ depending on the values specified in the EER flag and DCR flag in the MODE SELECT parameters.

If immediate correction of errors is permitted (DCR = 0, EER = 1), the IDD immediately makes error corrections in the data buffer and sends the corrected data to the INIT. Also, in the case of Verify processing, at the point when it judges that correction is possible, it regards verification as being successful and continues processing of subsequent data blocks.

5 - 22

C141-E167

Page 255 Page 257
Page 256
Image 256
Fujitsu MAP3147, MAP3367, MAS3735 Disk Drive Error Recovery Processing, Error states and retry processing procedures
Page 255 Page 257

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.
Top Page Image Contents