Streaming Logs | Hitachi HDS721075CLA632, HCS721050CLA382, A7K2000

9.13.1.1Urgent bit

The Urgent bit in the Read Stream and Write Stream commands specifies that the command should be completed in the minimum possible time by the device and shall be completed within the specified Command Completion Time Limit.

9.13.1.2Flush to Disk bit

The Flush to Disk bit in the Write Stream command specifies that all data for the specified stream shall be flushed to the media before posting command completion. If a host requests flushes at times other than the end of each Allocation Unit, streaming performance may be degraded. The Set Features command to enable/disable caching shall not affect caching for streaming commands.

9.13.1.3Not Sequential bit

The Not Sequential bit specifies that the next read stream command with the same Stream ID may not be sequential in LBA space. This information helps the device with pre-fetching decisions.

9.13.1.4Read Continuous bit

If the Read Continuous bit is set to one for the command, the device shall transfer the requested amount of data to the host within the Command Completion Time Limit even if an error occurs. The data sent to the host by the device in an error condition is vendor specific.

9.13.1.5Write Continuous bit

If the Write Continuous bit is set to one for the command, and an error is encountered, the device shall complete the request without posting an error. If an error cannot be resolved within the Command Completion Time Limit, the erroneous section on the media may be unchanged or may contain undefined data. A future read of this area may not report an error, even though the data is erroneous.

9.13.1.6Handle Streaming Error bit

The Handle Streaming Error bit specifies to the device that this command starts at the LBA of a recently reported error section, so the device may attempt to continue its corresponding error recovery sequence where it left off earlier. This mechanism allows the host to schedule error recovery and defect management for content critical data.

9.13.2Streaming Logs

The Streaming Data Transfer feature set requires two error logs and one performance log. These logs are accessed via the Read Log Ext command; the information included in the error logs is volatile and is not maintained across power cycles, hard resets, or sleep. These error logs are 512 bytes in length and retain the last 31 errors that occurred during any Streaming Data transfer.

Hitachi hard disk drive specifications

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.

Hitachi's hard drives incorporate various technologies that enhance their performance and durability. Features such as staggered start-up, which gradually powers on the drive, help minimize power surges and increase the longevity of the device. Moreover, Hitachi's commitment to quality ensures that each drive undergoes rigorous testing, guaranteeing functionality and reliability.

Overall, the diverse range of models from Hitachi provides effective solutions for anyone from casual users to enterprises, combining storage capacity with advanced technologies to meet the evolving demands of modern data storage.