Hard disk drive

lastmod 2025-02-17created 2014-09-2716 edits

A hard disk drive is a non-volatile, sequential-access secondary storage device for computers. It records information as magnetic patterns on rotating platters inside a protective case, and is characterized by a spindle motor that drives these platters. Data is recorded on a magnetic material coated on the platter surfaces, and is read and written magnetically by input/output heads that float above the rotating platters.

A hard disk is a magnetic recording medium like a floppy disk, but unlike a floppy disk it records on metal platters, so it was named "hard" to mean rigid. In general, it is still widely used as an indispensable storage medium for holding the operating system of personal computers. Solid-state drives, semiconductor-based recording media superior in many characteristics, are gradually entering the storage media market as their prices fall, but because their price per unit of storage capacity is higher than that of hard disks, hard disks are still used as an important storage medium despite the performance advantage of SSDs.

Categories

• Disk sector
• Cylinder-head-sector (CHS)
• Logical block addressing (LBA)
• Advanced Format (AF)
• Data striping
• RAID
• Managing Disk Space - Notes on issues when disk space runs low.

Personal thoughts on NAS communication bandwidth

Assuming an internal network,

• A server with an SSD installed sustains about 11Mbps
• A server with an HDD installed sustains about 300Kbps

Backblaze Hard Drive Stats

• [Recommended] Hard Drive Data and Stats (Test Data)

Quarterly HDD test results published by Backblaze. In recent hardware communities, it is effectively used as one of the most authoritative sources for evaluating hard drives.

To summarize very briefly: hard drives made by Seagate are the most unstable, Western Digital and Toshiba hard drives are decent, and the HGST brand fails the least.

Reports

Backblaze Hard Drive Stats for 2020

https://www.backblaze.com/blog/backblaze-hard-drive-stats-for-2020/

Based on reliability for NAS: bought HGST - HMS5C4040BLE640 (4TB) enterprise. (2021-03-16)

Troubleshooting

When the hard disk drive is not recognized

• SR-IOV
• What is SR-IOV (Single Root I/O Virtualization)?
• Best practices for Intel® Server System Baseboard Management Controller (BMC) and BIOS security
• What is a Baseboard Management Controller (BMC)? - Definition from techopedia - IT management 2023

When using an Intel CPU with an HDD using GPT and installing Ubuntu... there was a report that tweaking sr-iov and bmc in the Bios made it work.

Documentation

Failure Trends in a Large Disk Drive Population (Google Inc)

https://static.googleusercontent.com/media/research.google.com/ko//archive/disk_failures.pdf

• jasu's blog :: Google tests 100,000 HDDs.

Favorite site

• Wikipedia (en) description of hard disk drive
• How does permanent hard disk erasure work?
• [Recommended] WEBDIR :: Understanding the hard disk ¹ (GPT, Disk sector, UEFI, Partition table, CHS, LBA)

References