Difference between revisions of "Hard disk drive"

From Pulsed Media Wiki
(→‎Information)
 
(→‎Guides: →‎Linux: →‎Information: →‎Pulsed Media)
 
Line 1: Line 1:
 +
= Hard Disk Drive (HDD) =
  
−
A '''hard disk drive''' ('''HDD''') is an [[electromechanics|electromechanical]] [[Computer storage|data storage device]] that stores and retrieves digital [[Data|data]] using [[Magnetism|magnetic]] storage. It uses one or more rigid, rapidly rotating disks ([[platter]]s) coated with magnetic material. Data is written to and read from the platters by [[Read/write head|magnetic heads]], typically mounted on a movable arm called an [[Actuator (computing)|actuator arm]]. HDDs are a form of [[Non-volatile memory|non-volatile storage]], meaning they retain stored data even when powered off.  
+
A Hard Disk Drive (HDD) is an electromechanical device used for storing digital data. It stores and retrieves information using magnetic storage on one or more rapidly spinning disks, called platters. Data is written to and read from these platters by magnetic heads, which move across the disk surfaces on an arm. HDDs are a form of permanent storage, meaning they keep your data even when the power is off.
  
−
For many years, HDDs were the primary form of secondary storage for [[Computer system|computer systems]], storing operating systems, applications, and user files.  
+
For many years, HDDs were the main type of storage in computers for operating systems, applications, and user files.
  
−
== Overview and Purpose ==
+
== What HDDs are For ==
−
HDDs provide persistent storage for digital data. Unlike [[Random-access memory|RAM]], which is volatile and loses data when the power is removed, HDDs retain data indefinitely until it is intentionally erased or the drive fails. They offer high storage capacity at a relatively low cost per gigabyte, making them suitable for storing large amounts of data.  
+
HDDs provide lasting storage for digital information. Unlike temporary computer memory (RAM), HDDs hold onto data indefinitely until you remove it or the drive breaks. They offer large storage capacities at a relatively low cost per gigabyte, making them ideal for holding vast amounts of data.
  
−
The performance of an HDD is limited by the speed at which the platters spin and the time it takes for the read/write heads to move to the correct location on the platters.
+
The speed of an HDD is affected by how fast the platters spin and how long it takes for the read/write heads to find the correct spot on the disk.
  
−
== Basic Components ==
+
== Main Parts of an HDD ==
−
A typical hard disk drive consists of several key physical components enclosed in a sealed case to protect them from dust and contaminants:  
+
An HDD has several key physical parts inside a sealed case:
  
−
; Platters
+
Platters: These are rigid, circular disks with a magnetic coating where data is stored. Several platters are often stacked together.
−
: Rigid, circular disks made of aluminum, glass, or ceramic, coated with a magnetic material. Data is stored magnetically on the surfaces of these platters. Multiple platters are often stacked on a central spindle.  
 
  
−
; Spindle Motor
+
Spindle Motor: This motor spins the platters at a constant high speed (e.g., 7,200 revolutions per minute).
−
: Rotates the platters at a high, constant speed (measured in revolutions per minute or RPM). Common speeds include 5,400, 7,200, 10,000, and 15,000 RPM.  
 
  
−
; Read/Write Heads
+
Read/Write Heads: Tiny electromagnets on the end of an arm that read and write data. They float just above the platter surface.
−
: Tiny electromagnets mounted at the end of the actuator arms. There is typically one head for each surface of each platter. The heads do not touch the platter surface but "fly" on a cushion of air created by the spinning platters.  
 
  
−
; Actuator Arm (or Access Arm)
+
Actuator Arm: A movable arm that holds the read/write heads and moves them across the platters to access different data areas.
−
: A movable arm that holds the read/write heads. Controlled by an actuator mechanism (often a voice coil motor), it moves the heads back and forth across the platter surfaces to position them over the correct data tracks.  
 
  
−
; Logic Board (Printed Circuit Board - PCB)
+
Logic Board (PCB): The electronic circuit board that controls the drive's operations, managing data transfer and head movements.
−
: Contains the electronic components that control the drive's operations. This includes the drive's controller, which manages data transfer between the drive and the computer's interface, error correction, and the operations of the spindle motor and actuator arm.  
 
  
−
== How it Works ==
+
== How an HDD Works ==
−
When the computer needs to read or write data from or to the HDD:
+
When your computer needs to access data on the HDD:
  
−
The spindle motor spins the platters up to their operating speed.  
+
The spindle motor spins the platters to full speed.
−
The actuator arm moves the read/write heads across the platters to the correct radial position, locating the specific data track.  
+
 
−
As the relevant sector on the track spins under the head, the head either:
+
The actuator arm moves the read/write heads to the correct position over the data track.
−
'''Reads:''' Detects the magnetic polarization of tiny areas on the platter surface and converts this into electrical signals, which the logic board translates into digital data.  
+
 
−
'''Writes:''' Sends electrical pulses to the head, which magnetizes tiny areas on the platter surface with the appropriate polarization to represent digital data.  
+
As the specific data spot spins under the head, the head either:
−
The logic board manages the data flow between the heads and the computer's storage interface.
+
 
−
The time it takes to position the heads over the correct track (seek time) and wait for the correct sector to rotate under the head (rotational latency) are significant factors limiting HDD performance, especially for random data access.  
+
Reads: Detects magnetic changes and converts them into digital data.
 +
 
 +
Writes: Changes the magnetic polarization on the platter surface to store digital data.
 +
 
 +
The time it takes for the heads to move and for the correct data to spin into place are the main factors limiting HDD performance, especially for quickly accessing scattered pieces of data.
  
 
== HDD vs. SSD Comparison ==
 
== HDD vs. SSD Comparison ==
Line 44: Line 44:
 
|-
 
|-
 
! Feature
 
! Feature
−
! [[Hard disk drive|HDD]]
+
! HDD
−
! [[Solid-state drive|SSD]]
+
! SSD
 
|-
 
|-
−
! Moving Parts
+
| '''Moving Parts'''
−
| Yes (platters spin, arm moves)
+
| Yes (spinning platters, moving arm)
 
| No (all electronic)
 
| No (all electronic)
 
|-
 
|-
−
! Speed (Access Time)
+
| '''Speed (Access)'''
−
| Slower (milliseconds due to mechanical movement)
+
| Slower (milliseconds)
 
| Much Faster (microseconds)
 
| Much Faster (microseconds)
 
|-
 
|-
−
! Speed (Sequential Throughput)
+
| '''Speed (Overall)'''
−
| Slower (e.g., up to ~250 MB/s for SATA HDDs)
+
| Slower (up to ~250 MB/s for common types)
−
| Much Faster (e.g., up to ~550 MB/s for SATA SSDs, several GB/s for NVMe SSDs)
+
| Much Faster (hundreds to thousands of MB/s)
−
|-
 
−
! Speed (Random IOPS)
 
−
| Much Lower
 
−
| Much Higher
 
 
|-
 
|-
−
! Durability (Shock/Vibration)
+
| '''Durability'''
−
| Lower (vulnerable to physical impact during operation)
+
| Lower (sensitive to shock/vibration)
 
| Higher (more resistant)
 
| Higher (more resistant)
 
|-
 
|-
−
! Power Consumption
+
| '''Power Use'''
−
| Higher (especially during spin-up and seeking)
+
| Higher
 
| Lower
 
| Lower
 
|-
 
|-
−
! Noise
+
| '''Noise'''
−
| Audible (spinning platters, head movement)
+
| Can be audible
 
| Silent
 
| Silent
 
|-
 
|-
−
! Cost per Gigabyte
+
| '''Cost per GB'''
 
| Lower
 
| Lower
 
| Higher
 
| Higher
 
|-
 
|-
−
! Maximum Capacity
+
| '''Capacity'''
−
| Typically higher maximum capacities available (e.g., 20+ TB)
+
| Typically higher max capacities
−
| Max capacities are increasing but often trail HDDs at the highest tiers
+
| Max capacities increasing, but often trail HDDs
−
|}  
+
|}
−
 
 
−
== HDD Interfaces ==
 
−
HDDs connect to the computer's [[Motherboard|motherboard]] via standard interfaces:  
 
−
 
 
−
'''[[SATA]] (Serial ATA):''' The most common interface for consumer and enterprise HDDs, offering up to 6 Gbit/s (SATA III) throughput.  
 
−
'''[[SAS]] (Serial Attached SCSI):''' A more robust interface typically used in enterprise environments, offering higher speeds (e.g., 12 Gbit/s, 24 Gbit/s), dual-port capabilities, and better suitability for demanding server workloads.  
 
−
'''[[Parallel ATA|PATA]] (Parallel ATA):''' An older, slower interface that was replaced by SATA.  
 
−
'''[[USB]] (Universal Serial Bus):''' Used for external hard drives.  
 
−
== HDD Performance Metrics ==
 
−
Key metrics for evaluating HDD performance include:
 
−
 
 
−
'''[[Clock rate|Rotational Speed (RPM)]]:''' How fast the platters spin. Higher RPMs (like 7,200 or 15,000) generally mean lower rotational latency and higher data transfer rates.  
 
−
'''[[Data transfer rate|Transfer Rate]]:''' The speed at which data can be read from or written to the platters sequentially (e.g., MB/s). This is fastest on the outer tracks.
 
−
'''Seek Time / Latency:''' The average time it takes for the read/write heads to move to a specific track and for the desired sector to rotate under the head. This is the biggest performance bottleneck compared to SSDs.  
 
−
'''[[Input/output operations per second|IOPS]] (Input/Output Operations Per Second):''' A measure of the number of random read or write operations a drive can perform per second, heavily impacted by seek time and rotational latency for HDDs.  
 
−
== HDD Usage Areas ==
 
−
Despite the rise of SSDs, HDDs remain relevant and widely used for specific applications:
 
  
−
'''Bulk Data Storage:''' Storing large volumes of data where cost per gigabyte is a primary concern (e.g., large media libraries, archives, data lakes).
 
−
'''Backups:''' Storing backups of data due to their high capacity and lower cost.  
 
−
'''Archiving:''' Long-term storage of data that is not frequently accessed.  
 
−
'''Server Storage:''' Used in servers, particularly for workloads that involve large sequential writes or require massive capacity, where the performance characteristics of SSDs are not strictly necessary for all data tiers.
 
−
== HDDs in Pulsed Media Services ==
 
  
−
[[Pulsed Media]], like many hosting providers offering storage-intensive services, utilizes [[Hard disk drive|HDDs]] alongside [[Solid-state drive|SSDs]] to cater to different performance and capacity needs. While SSDs are often used for operating systems or performance-critical applications, HDDs are fundamental for providing the large-capacity storage that services like [[Seedbox|seedboxes]] and certain types of [[Virtual private server|VPS]] or [[Dedicated server|dedicated server]] plans require.  
 
  
−
Pulsed Media utilizes '''fast and powerful enterprise-grade HDDs''' for offering its [[Computer storage|storage service]]s, particularly for providing ample storage space for users' files. These are not standard consumer desktop drives but are designed for the demanding environment of continuous server operation:
+
== Typical Uses ==
 +
Even with the rise of SSDs, HDDs are still widely used for specific tasks:
  
−
'''Higher Reliability:''' Enterprise drives have higher Mean Time Between Failures (MTBF) ratings and are built for 24/7 operation.  
+
Bulk Data Storage: Storing very large amounts of data where cost is a main concern, such as large media libraries or archives.
−
'''Performance:''' Often feature higher RPMs (like 7,200 RPM or more) and use [[SAS]] interfaces for better performance and connectivity options in server arrays compared to consumer SATA drives.
 
−
'''Designed for Servers:''' Include features like enhanced error correction, vibration resistance, and consistent performance needed in multi-drive server configurations and [[RAID]] arrays.  
 
−
'''High Capacity:''' Enable offering large storage quotas that would be prohibitively expensive with SSDs.
 
−
By using enterprise-grade HDDs, Pulsed Media can offer reliable, high-capacity storage services that meet the needs of users requiring significant space for their data, complementing their use of SSDs for performance-sensitive applications or service tiers. The specific speed and reliability users experience depend on the exact drive models and the [[RAID]] configuration used in the underlying server infrastructure.
 
  
−
== See also ==
+
Backups: Storing copies of data due to their high capacity and lower cost.
  
−
[[Solid-state drive|SSD]]
+
Archiving: Long-term storage of data that isn't accessed often.
−
 
−
[[Computer storage]]
 
−
 
−
[[Magnetic storage]]
 
  
−
[[Flash memory]]
+
Server Storage: Used in servers, especially for tasks involving large data writes or requiring huge storage capacity where extreme speed isn't needed for all data.
  
−
[[SATA]]  
+
== HDDs in [[Pulsed Media]] Services ==
 +
Pulsed Media, as a hosting provider offering storage-heavy services, extensively uses Hard Disk Drives (HDDs) alongside Solid-State Drives (SSDs) to meet various performance and capacity demands. While SSDs are reserved for fast-access needs, HDDs are crucial for providing the vast storage required for services like seedboxes and certain Virtual Private Server (VPS) or dedicated server plans.
  
−
[[SAS]]
+
Pulsed Media employs fast and powerful enterprise-grade HDDs to deliver its storage services, providing ample space for user files. These are not standard drives found in home computers; they are built for the demanding, continuous operation of server environments:
  
−
[[RAID]]
+
Higher Reliability: Enterprise drives are designed for 24/7 use and have a much longer lifespan in server conditions.
  
−
[[RPM]]
+
Performance: They often spin faster (like 7,200 RPM or more) and use advanced interfaces (like SAS) for better performance and connectivity within large server setups, outperforming typical consumer drives.
  
−
[[Pulsed Media]]
+
Server-Optimized: These drives include features like improved error correction and vibration resistance, which are essential for stable performance in servers with many drives working together in RAID configurations.
  
−
== External links ==
+
High Capacity: They make it possible for [[Pulsed Media]] to offer massive storage quotas that would be too expensive to provide with SSDs alone.
  
−
[https://www.google.com/search?q=https://www.computerhope.com/jargon/h/harddisk.htm Computer Hope: Hard disk drive]
+
By using these high-quality, enterprise-grade HDDs, Pulsed Media offers reliable and cost-effective high-capacity storage services. This setup perfectly complements their use of SSDs, ensuring that users get the right balance of speed and space for all their data needs. The actual speed and reliability you experience depend on the specific drive models and how they are arranged in the server infrastructure, often using RAID technology for better performance or data protection.
  
−
[https://www.seagate.com/products/enterprise-drives/ Seagate Enterprise Drives Information]
 
  
−
[https://www.google.com/search?q=https://www.backblaze.com/blog/hdd-versus-ssd/ Backblaze: HDD vs SSD] (Includes real-world reliability data)
+
== See Also ==
  
 +
*[[SSD]]
 +
*[[HDD]]
  
−
[[Category:Hard disk drives]]
+
[[Category:Information]]
−
[[Category:Computer storage]]
 
−
[[Category:Magnetic storage]]
 
−
[[Category:Computer hardware]]
 
−
[[Category:Electromechanical devices]]
 
−
[[Category:Technical terms]]
 
−
[[Category:Pulsed Media]]
 

Latest revision as of 08:27, 10 June 2025

Hard Disk Drive (HDD)

A Hard Disk Drive (HDD) is an electromechanical device used for storing digital data. It stores and retrieves information using magnetic storage on one or more rapidly spinning disks, called platters. Data is written to and read from these platters by magnetic heads, which move across the disk surfaces on an arm. HDDs are a form of permanent storage, meaning they keep your data even when the power is off.

For many years, HDDs were the main type of storage in computers for operating systems, applications, and user files.

What HDDs are For

HDDs provide lasting storage for digital information. Unlike temporary computer memory (RAM), HDDs hold onto data indefinitely until you remove it or the drive breaks. They offer large storage capacities at a relatively low cost per gigabyte, making them ideal for holding vast amounts of data.

The speed of an HDD is affected by how fast the platters spin and how long it takes for the read/write heads to find the correct spot on the disk.

Main Parts of an HDD

An HDD has several key physical parts inside a sealed case:

Platters: These are rigid, circular disks with a magnetic coating where data is stored. Several platters are often stacked together.

Spindle Motor: This motor spins the platters at a constant high speed (e.g., 7,200 revolutions per minute).

Read/Write Heads: Tiny electromagnets on the end of an arm that read and write data. They float just above the platter surface.

Actuator Arm: A movable arm that holds the read/write heads and moves them across the platters to access different data areas.

Logic Board (PCB): The electronic circuit board that controls the drive's operations, managing data transfer and head movements.

How an HDD Works

When your computer needs to access data on the HDD:

The spindle motor spins the platters to full speed.

The actuator arm moves the read/write heads to the correct position over the data track.

As the specific data spot spins under the head, the head either:

Reads: Detects magnetic changes and converts them into digital data.

Writes: Changes the magnetic polarization on the platter surface to store digital data.

The time it takes for the heads to move and for the correct data to spin into place are the main factors limiting HDD performance, especially for quickly accessing scattered pieces of data.

HDD vs. SSD Comparison

Comparison of Hard Disk Drives and Solid-State Drives
Feature HDD SSD
Moving Parts Yes (spinning platters, moving arm) No (all electronic)
Speed (Access) Slower (milliseconds) Much Faster (microseconds)
Speed (Overall) Slower (up to ~250 MB/s for common types) Much Faster (hundreds to thousands of MB/s)
Durability Lower (sensitive to shock/vibration) Higher (more resistant)
Power Use Higher Lower
Noise Can be audible Silent
Cost per GB Lower Higher
Capacity Typically higher max capacities Max capacities increasing, but often trail HDDs


Typical Uses

Even with the rise of SSDs, HDDs are still widely used for specific tasks:

Bulk Data Storage: Storing very large amounts of data where cost is a main concern, such as large media libraries or archives.

Backups: Storing copies of data due to their high capacity and lower cost.

Archiving: Long-term storage of data that isn't accessed often.

Server Storage: Used in servers, especially for tasks involving large data writes or requiring huge storage capacity where extreme speed isn't needed for all data.

HDDs in Pulsed Media Services

Pulsed Media, as a hosting provider offering storage-heavy services, extensively uses Hard Disk Drives (HDDs) alongside Solid-State Drives (SSDs) to meet various performance and capacity demands. While SSDs are reserved for fast-access needs, HDDs are crucial for providing the vast storage required for services like seedboxes and certain Virtual Private Server (VPS) or dedicated server plans.

Pulsed Media employs fast and powerful enterprise-grade HDDs to deliver its storage services, providing ample space for user files. These are not standard drives found in home computers; they are built for the demanding, continuous operation of server environments:

Higher Reliability: Enterprise drives are designed for 24/7 use and have a much longer lifespan in server conditions.

Performance: They often spin faster (like 7,200 RPM or more) and use advanced interfaces (like SAS) for better performance and connectivity within large server setups, outperforming typical consumer drives.

Server-Optimized: These drives include features like improved error correction and vibration resistance, which are essential for stable performance in servers with many drives working together in RAID configurations.

High Capacity: They make it possible for Pulsed Media to offer massive storage quotas that would be too expensive to provide with SSDs alone.

By using these high-quality, enterprise-grade HDDs, Pulsed Media offers reliable and cost-effective high-capacity storage services. This setup perfectly complements their use of SSDs, ensuring that users get the right balance of speed and space for all their data needs. The actual speed and reliability you experience depend on the specific drive models and how they are arranged in the server infrastructure, often using RAID technology for better performance or data protection.


See Also

Retrieved from "https://wiki.pulsedmedia.com/index.php?title=Hard_disk_drive&oldid=1003123"