7K200 SATA OEM Specification

12.3 Power-off considerations

12.3.1Load/Unload

Load/Unload is a functional mechanism of the HDD. It is controlled by the drive microcode. Specifically, unloading of the heads is invoked by the commands:

Command

Standby

Standby immediate

Sleep

Response

UL -> Comp.

UL -> Comp.

UL -> Comp.

“UL” means “unload”.

“Comp” means “complete”.

Table 33 Device’s behavior by ATA commands

Load/unload is also invoked as one of the idle modes of the drive.

The specified start/stop life of the product assumes that load/unload is operated normally, NOT in emergency mode.

12.3.2Emergency unload

When HDD power is interrupted while the heads are still loaded, the microcode cannot operate and the normal 5V power is unavailable to unload the heads. In this case, normal unload is not possible, so the heads are unloaded by routing the back-EMF of the spinning motor to the voice coil. The actuator velocity is greater than the normal case, and the unload process is inherently less controllable without a normal seek current profile.

Emergency unload is intended to be invoked in rare situations. Because this operation is inherently uncontrolled, it is more mechanically stressful than a normal unload.

A single emergency unload operation is more stressful than 100 normal unloads. Use of emergency unload reduces the start/stop life of the HDD at a rate at least 100X faster than that of normal unload, and may damage the HDD.

12.3.3Required power-off sequence

Problems can occur on most HDDs when power is removed at an arbitrary time. Examples:

Data loss from the write buffer.

If the drive is writing a sector, a partially-written sector with an incorrect ECC block results. The sector contents are destroyed and reading that sector results in a hard error.

Heads possibly land in the data zone instead of landing zone, depending on the design of the HDD. You may then turn off the HDD in the following order:

1.Issue Standby Immediate or sleep command.

2.Wait until COMMAND COMPLETE STATUS is returned. (It may take up to 350 ms in typical case)

3.Terminate power to HDD.

This power-down sequence should be followed for entry into any system power-down state, or system suspend state, or system hibernation state. In a robustly designed system, emergency unload is limited to rare scenarios such as battery removal during operation.

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Hitachi HDS723020BLA642 manual Power-off considerations, Emergency unload, Required power-off sequence
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HDS723020BLA642 specifications

The Hitachi HDS723020BLA642 is a high-performance hard disk drive that exemplifies the balance between reliability and advanced technology, making it an excellent choice for a range of applications, from desktop computers to enterprise storage solutions. This 2TB SATA hard drive is designed to meet the growing data storage needs of users who demand both speed and efficiency.

One of the key features of the HDS723020BLA642 is its impressive rotational speed of 7200 RPM. This speed facilitates faster data access and improved overall performance, significantly enhancing the user experience during data-intensive operations such as gaming, video editing, and large file transfers. Coupled with a SATA III interface, this drive facilitates data transfer rates of up to 6 Gb/s, providing an efficient conduit for moving data quickly between the hard drive and the motherboard.

The drive comes equipped with a large 64 MB cache, which plays a crucial role in buffering read and write operations. This substantial amount of cache memory allows the drive to temporarily store frequently accessed data, leading to reduced latency and enabling smoother multitasking capabilities. Users will benefit from faster load times and reduced wait periods when working with large files.

Reliability is another defining characteristic of the HDS723020BLA642. Hitachi, now a part of Western Digital, has a longstanding reputation for producing durable hard drives. This model incorporates advanced technologies, such as the Fluid Dynamic Bearing (FDB) for quieter operation and better longevity. The drive also features an enhanced error recovery system that minimizes the risk of data loss, making it a suitable option for both personal and professional use.

In terms of power efficiency, the HDS723020BLA642 is designed to consume less power during operation compared to older hard drive models. This efficiency not only helps in reducing operational costs but also contributes to a longer lifespan for the drive itself.

Overall, the Hitachi HDS723020BLA642 hard drive combines speed, reliability, and efficiency into a compact package, making it an ideal choice for users needing a substantial amount of storage without compromising on performance. Whether for upgrading an existing system or building a new one, this drive offers a blend of technology and durability that caters to modern storage demands.
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