10.0Defect and error management

Seagate continues to use innovative technologies to manage defects and errors. These technologies are designed to increase data integrity, perform drive self-maintenance, and validate proper drive operation.

SCSI defect and error management involves drive internal defect/error management and SAS system error considerations (errors in communications between the initiator and the drive). In addition, Seagate provides the following technologies used to increase data integrity and drive reliability:

•Background Media Scan (see Section 10.4)

•Media Pre-Scan (see Section 10.5)

•Deferred Auto-Reallocation (see Section 10.6)

•Idle Read After Write (see Section 10.7)

The read error rates and specified storage capacities are not dependent on host (initiator) defect management routines.

10.1Drive internal defects/errors

During the initial drive format operation at the factory, media defects are identified, tagged as being unusable, and their locations recorded on the drive primary defects list (referred to as the “P’ list and also as the ETF defect list). At factory format time, these known defects are also reallocated, that is, reassigned to a new place on the medium and the location listed in the defects reallocation table. The “P” list is not altered after factory formatting. Locations of defects found and reallocated during error recovery procedures after drive shipment are listed in the “G” list (defects growth list). The “P” and “G” lists may be referenced by the initiator using the Read Defect Data command.

Details of the SCSI commands supported by the drive are described in the SAS Interface Manual. Also, more information on the drive Error Recovery philosophy is presented in the SAS Interface Manual.

10.2Drive error recovery procedures

When an error occurs during drive operation, the drive, if programmed to do so, performs error recovery proce- dures to attempt to recover the data. The error recovery procedures used depend on the options previously set in the Error Recovery Parameters mode page. Error recovery and defect management may involve using sev- eral SCSI commands described in the SAS Interface Manual. The drive implements selectable error recovery time limits required in video applications.

The error recovery scheme supported by the drive provides a way to control the total error recovery time for the entire command in addition to controlling the recovery level for a single LBA. The total amount of time spent in error recovery for a command can be limited using the Recovery Time Limit bytes in the Error Recovery mode page. The total amount of time spent in error recovery for a single LBA can be limited using the Read Retry Count or Write Retry Count bytes in the Error Recovery mode page.

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Seagate ST1000NM0001 manual Defect and error management, Drive internal defects/errors, Drive error recovery procedures
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ST2000NM0001, ST1000NM0041, ST500NM0001, ST2000NM0021, ST1000NM0021 specifications

Seagate is a renowned leader in data storage solutions, offering a wide array of hard disk drives (HDDs) suitable for various applications. Among their product lineup, the Seagate ST2000NM0041, ST500NM0021, ST500NM0041, ST1000NM0001, and ST1000NM0021 stand out as reliable options tailored for enterprise environments and general storage needs.

The Seagate ST2000NM0041 is a 2TB 7200 RPM drive designed for high-performance workloads in data centers. One of its key features is the use of the SATA III interface, providing data transfer speeds of up to 6 Gbps, ensuring quick access to data. This model supports advanced error recovery controls and features enhanced power management capabilities, which contribute to its reliable performance and energy efficiency.

Next, the ST500NM0021 and ST500NM0041 are both 500GB drives that cater to different consumer needs. The ST500NM0021 is a 5400 RPM drive, typically used in scenarios where lower power consumption is vital, such as in compact systems or external storage configurations. Its efficient design enables quieter operation, making it ideal for environments that require minimal noise. Conversely, the ST500NM0041 operates at a speed of 7200 RPM, making it suitable for more demanding applications that require swift read and write speeds. Both models utilize Serial ATA for connectivity, ensuring compatibility with a wide range of systems.

The ST1000NM0001 and ST1000NM0021 are 1TB drives that provide versatility across different platforms. Similar to their 500GB counterparts, the ST1000NM0001 features a 7200 RPM speed, optimizing performance for applications requiring faster data processing. In contrast, the ST1000NM0021 operates at 5400 RPM, designed for users prioritizing energy efficiency over speed, like in desktop and external storage solutions. Each of these drives supports advanced technologies such as Native Command Queuing (NCQ), which enhances performance by allowing multiple commands to be executed simultaneously.

Overall, the Seagate ST series hard drives offer flexible storage options for a variety of applications. With their robust features, including varied RPM speeds, power management, and compatibility with SATA connections, these drives cater to the needs of both consumer and enterprise markets, establishing Seagate as a trusted provider in the storage arena.
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