Streaming Performance log | Hitachi HDS721010CLA632, A7K2000

11.18.7 Streaming Performance log

Table 112 defines the format of the log returned by the Read Log Ext command, when the LBA Low register is 20h. This data set is referred to as the Streaming Performance Parameters log, the length of which (in sectors) is statically indicated in Read Log Ext log address 00h (Log Directory).

The host should base its calculations on the larger of its Typical Host Interface Sector Time and the device reported Sector Time values, and on the sum of the device reported Access Time values and any additional latency that only the host is aware of (e.g. host command overhead, etc.).

Description	Bytes

Stream Performance Parameters log version	2

K, Number of Regions in Sector Time Array	2

L, Number of Positions in Position Array	2

M, Number of Position-differences in Access Time Array	2

Sector Time Array	K*8

Position Array	L*8

Access Time Array	M*4

Reserved

Table 112 Streaming Performance Parameters log

Description	Bytes

LBA of reference location (LBA(7:0)...LBA(47:40))	n-(n+5)

(Identify Device words (99:98))/65536 time units per sector at the reference location	(n+6)-(n+7)

Table 113 Sector Time Array Entry (Linearly Interpolated)

Description

LBA of start of region (LBA(7:0)...LBA(47:40))

Position number in the range 0...32767

Bytes

n-(n+5)

(n+6)-(n+7)


Table 114		Position Array Entry (Linearly Interpolated)

	Description		Bytes

	Difference in position from last stream access to new stream access		n-(n+1)
	Time that may be required to begin access at new stream access position, in		(n+2)-(n+3)
	(Identify Device words (99:98))/256 time units

Table 115		Access Time Array Entry (Linearly Interpolated)

Hitachi hard disk drive specifications

156

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.

On the other hand, the DSDS7210C09EN-04 is a part of Hitachi's enterprise-oriented offerings. This drive is engineered for demanding applications, featuring advanced technologies such as error recovery controls and enhanced data protection features. With a focus on reliability and performance, the DSDS7210C09EN-04 serves well in server environments and for high-performance computing.

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