5.3 Host Commands

(2) READ SECTOR(S) (X’20’ or X’21’)

This command reads data of sectors specified in the Sector Count register from the address specified in the Device/Head, Cylinder High, Cylinder Low and Sector Number registers. Number of sectors can be specified from 1 to 256 sectors. To specify 256 sectors reading, ‘00’ is specified. For the DRQ, INTRQ, and BSY protocols related to data transfer, see Subsection 5.4.1.

If the head is not on the track specified by the host, the device performs an implied seek. After the head reaches to the specified track, the device reads the target sector.

If an error occurs, retry reads are attempted to read the target sector before reporting an error, irrespective of the R bit setting.

The DRQ bit of the Status register is always set prior to the data transfer regardless of an error condition.

Upon the completion of the command execution, command block registers contain the cylinder, head, and sector addresses (in the CHS mode) or logical block address (in the LBA mode) of the last sector read.

If an unrecoverable error occurs in a sector, the read operation is terminated at the sector where the error occurred. Command block registers contain the cylinder, the head, and the sector addresses of the sector (in the CHS mode) or the logical block address (in the LBA mode) where the error occurred, and remaining number of sectors of which data was not transferred.

At command issuance (I/O registers setting contents)

1F7H(CM)

0

0

1

0

0

0

0

R

1F6H(DH)

x

L

x

DV

Start head No. / LBA

 

 

 

 

 

 

[MSB]

 

 

 

1F5H(CH)

Start cylinder No. [MSB] / LBA

 

 

 

1F4H(CL)

Start cylinder No. [LSB] / LBA

 

 

 

1F3H(SN)

Start sector No. / LBA [LSB]

 

 

 

1F2H(SC)

Transfer sector count

 

 

 

 

1F1H(FR)

xx

 

 

 

 

 

 

 

C141-E258

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Fujitsu MHW2040AC, MHW2060AC manual Read Sectors X’20’ or X’21’, Msb
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MHW2060AC, MHW2040AC specifications

The Fujitsu MHW2040AC and MHW2060AC are notable hard disk drives (HDDs) that have been widely used in various computing applications, especially in laptops and compact devices. These models are part of Fujitsu's commitment to providing reliable storage solutions that meet the demands of modern computing.

The MHW2040AC offers a storage capacity of 40 GB, while the MHW2060AC provides a slightly larger capacity at 60 GB. This range of storage makes both models suitable for users looking for dependable space for documents, multimedia files, and software applications. Both drives utilize a 2.5-inch form factor, ideal for mobile computing, as they are lightweight and designed to fit into space-constrained environments.

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In summary, the Fujitsu MHW2040AC and MHW2060AC are reliable, efficient, and user-friendly hard disk drives that combine moderate capacities with advanced features designed to enhance performance, ensure data integrity, and extend device longevity. These drives are well-suited for a range of applications, making them a solid choice for users seeking dependable storage solutions.
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