3.2 Data Access Commands

3.2Data Access Commands

3.2.1READ (08)

Bit

Byte

7

6

5

4

3

2

1

0

0

X‘08’

1

LUN

Logical Block Address (MSB)

2

Logical Block Address

3

Logical Block Address (LSB)

4

Transfer Block Count

5

0

0

0

0

0

0

0

Link

This command reads the number of blocks of data in continuous logical data blocks specified in the "Transfer block count" field with the logical data block on the disk media specified in the "Logical block address" field in the CDB as the top.

The transfer block count can be specified up to a maximum of 256 logical data blocks. When zero is specified in the "Transfer block count" field in byte 4 of the CDB, it specifies transfer of 256 logical data blocks and when a value other than zero is specified, it specifies the number of logical data blocks that should be transferred.

When transfer of multiple data blocks is instructed by this command, when the data blocks which are to be processed come to a track boundary, cylinder boundary or zone boundary, a head switch or cylinder switch is executed automatically and reading of the specified number of blocks is performed.

When the specifications in the "Logical block address" field and "Transfer block count" field in the CDB exceed the maximum logical block address in the IDD, that command is terminated with a CHECK CONDITION status (ILLEGAL REQUEST [=5] / Logical block address out of range [=21- 00]) and the reading of data from the disk media is not executed.

Error recovery processing during execution of this command can be specified by the MODE SELECT parameter. If retry processing and data correction processing are not prohibited, when this command is completed normally, or when it is completed with a "RECOVERED ERROR [=1]" sense key report, the data transferred to the INIT by this command are error free. When a correctable error check is detected, the IDD first corrects the data errors in the data buffer, then transfers those data to the INIT.

When disconnect processing is permitted, the starting timing for reconnection processing in order to execute data transfer on the SCSI bus can be specified by the MODE SELECT parameter (buffer full ratio). Also, if the Look-Ahead cache feature is permitted, a caching operation is performed using the IDD's data buffer by this command. See Chapter 2, "Data Buffer Management," concerning details of data buffer operation and the Look-Ahead cache feature.

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Fujitsu MAS3735, MAP3367, MAP3147, MAP3735, MAS3367 specifications Data Access Commands Read
Page 126 Page 128

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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