8.7Drive Address Register

Drive Address Register

7

HIZ

6

-WTG

5

-H3

4

-H2

3

-H1

2

-H0

1

-DS1

0

-DS0

Table 29 Drive Address Register

This register contains the inverted drive select and head select addresses of the currently selected drive.

Bit Definitions

HIZ

-WTG

-H3,-H2,-H1,-H0

-DS1

-DS0

High Impedance. This bit is not driven and will always be in a high impedance state.

-Write Gate. This bit is 0 when writing to the disk device is in progress.

-Head Select. These four bits are the one's complement of the binary coded address of the currently selected head. -H0 is the least significant.

-Drive Select 1. Drive select bit for device 1, active low. DS1=0 when device 1 (slave) is selected and active.

-Drive Select 0. Drive Select bit for device 0, active low. DS0=0 when device 0 (master) is selected and active.

8.8Device/Head Register

Device/Head Register

7

1

6

L

5

1

4

DRV

3

HS3

2

HS2

1

HS1

0

HS0

Table 30 Device/Head Register

This register contains the device and head numbers.

Bit Definitions

LBinary encoded address mode select. When L=0, addressing is by CHS mode. When L=1, addressing is by LBA mode.

DRV

Device. This product ignores this bit.

HS3,HS2,HS1,HS0 Head Select. These four bits indicate binary encoded address of the head. HS0 is the least significant bit. At command completion, these bits are updated to reflect the currently selected head.

The head number may be from zero to the number of heads minus one.

In LBA mode, HS3 through HS0 contain bits 24-27 of the LBA. At command completion, these bits are updated to reflect the current LBA bits 24-27.

Hitachi hard disk drive specifications

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Hitachi HUA722010CLA330/1, HCS721050CLA382, HCS721032CLA382, HCS721025CLA382 Drive Address Register, Device/Head Register

HCS721016CLA382, HCS721050CLA382, HCS721025CLA382, HDP725050GLA360, HUA722050CLA330/1 specifications

Hitachi's lineup of hard disk drives, including models such as HDS721075CLA632, HDS721032CLA362, HDS721032CLA662, HDS721050CLA362, and DSDS7210C09EN-04, offers a variety of features catering to different storage needs. These drives are widely recognized for their reliability, performance, and efficiency, making them suitable for both consumer and enterprise applications.

The HDS721075CLA632 model, with a capacity of 750GB, strikes a balance between performance and storage capabilities. It operates at 7200 RPM, ensuring quick access to data while maintaining low latency. Its 32MB cache enhances data transfer rates and improves overall system responsiveness. This HDD is particularly useful for gaming, multimedia, and office applications, allowing users to store a substantial amount of data with quick retrieval times.

The HDS721032CLA362 and HDS721032CLA662 share many similarities and are both designed for budget-conscious consumers. With a capacity of 320GB and a 7200 RPM, they offer efficient storage solutions for everyday tasks. The 32MB cache buffer enables efficient caching of frequently accessed files, providing a smooth experience for users.

Another notable model is the HDS721050CLA362, which features a capacity of 500GB. Like its counterparts, this drive operates at a speed of 7200 RPM and utilizes a 32MB cache, which ensures optimal performance for data-heavy applications. This model stands out for its energy efficiency, resulting in lower operational costs, making it an appealing choice for businesses and energy-conscious consumers alike.

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