A hard drive is one of the most important components in modern computing devices. It provides non-volatile data storage, meaning it retains data even when powered off. Hard drives have a wide variety of uses, both for individual consumers and in enterprise environments.
Quick Answers
Some quick answers to what a hard drive would be used for include:
- Operating system installation – The operating system boots from and runs off the hard drive
- Program and application storage – All software and apps are installed and run from the hard drive
- User file storage – Documents, photos, music, and other user files are stored on the hard drive
- Game storage – Games are installed and saved onto the hard drive
- Media storage – Movies, TV shows, and other media files are stored on the hard drive
Operating System Installation
One of the primary uses of a hard drive is to store the operating system. When a computer first boots up, it loads the operating system from the hard drive into memory and runs it from there. Without a hard drive, a computer cannot boot into an operating system.
Both Windows PCs and Macs require a hard drive for installation of their respective operating systems, such as Windows 10 or macOS. Servers also boot and run enterprise operating systems from hard drives. Operating systems require significant disk space, with modern versions like Windows 10 taking up 20GB or more.
The hard drive allows permanent storage of the OS and allows it to be safely modified and updated. If the OS was on volatile RAM alone, any changes would be lost every time the system powered off.
Program and Application Storage
Hard drives provide storage space for all types of software and applications. When new software is installed on a computer, it writes its program files to the hard drive. This includes things like:
- Productivity software like Microsoft Office
- Creative suites like Adobe Photoshop
- Games like Call of Duty
- Music production tools like Ableton Live
- And any other computer programs
Without a hard drive, apps and software could not be permanently stored and would need to be loaded in each time from an external source. Modern applications require significant storage space, with popular games like Call of Duty taking up over 100GB.
The hard drive allows users to build up a library of installed applications that they can access at any time after the initial install. It provides persistent storage so that all software data, settings, and preferences are safely maintained.
User File Storage
In addition to software, hard drives give users space to store their own personal files and documents. This includes:
- Documents – Word docs, PDFs, spreadsheets, etc.
- Pictures – JPEGs, RAW photos, PNGs, etc.
- Videos – MP4s, MOVs, AVI files
- Music – MP3s, WAVs, FLACs
Users can organize these files into folders and directories which are all cataloged by the file system on the hard drive. Files can be easily accessed later by navigating to their path.
Hard drive capacity allows people to accumulate large personal media libraries with thousands of files. For example, a 500GB hard drive could store over 100,000 songs or hundreds of hours of video.
Game Storage
Modern video game installations take up significant hard drive space. For example:
- Call of Duty: Modern Warfare (2019) – 175GB
- Red Dead Redemption 2 – 150GB
- Forza Horizon 4 – 100GB
Games of this size could not fit on smaller solid state drives, making large mechanical hard drives necessary. Games also require hard drive space for saving progress, downloaded updates, and downloadable content additions.
Console hard drives allow users to have libraries of installed games available to play instantly. On PCs, Steam and other game launchers enable managing and launching all games from a central interface.
Media Storage
Multimedia files like movies, TV shows, and music are also stored on hard drives. Media collectors and servers store thousands of files:
- Movie buffs have movie libraries spanning terabytes.
- Music collectors have extensive discographies in lossless audio.
- Photographers store thousands of RAW high res photos.
This amount of media storage is only possible with the large capacities of mechanical hard drives. For example, a 4TB drive could store over 500 HD movies.
Hard drives make built-up media libraries retrievable at any time. Often, external USB hard drives are used for extra storage and portability.
Other Consumer Uses
Hard drives have some other common uses on consumer devices:
- Game Consoles – Store game installs and saves.
- DVRs – Record live TV and allow pausing/rewinding live TV.
- Laptops – Store the operating system and files on the go.
- Media streamers – Store movies and shows locally for on-demand playback.
For all these devices, the hard drive enables robust local storage for large amounts of media and data.
Enterprise and Server Uses
Hard disk drives also have some key uses in enterprise IT and servers:
- File servers – Store company files and make them available over the network.
- Application servers – Host server applications and web apps.
- Database servers – Store large structured datasets for databases.
- Email servers – Store inboxes for company email accounts.
- Backup/archival – Make backups of critical data and archive old/inactive data.
Enterprise servers require reliable high capacity storage. Hard disk arrays with multiple drives can be configured for redundancy and extra capacity.
Primary Storage Medium
Hard disk drives became the primary form of everyday storage in computers starting in the 1960s. Their electro-mechanical engineering allowed much greater data density than predecessors like magnetic tape or drum memory. Their inexpensive per-bit cost made them ideal for the proliferating personal computer market starting in the 1980s.
Even with the advent of solid state flash storage in the 2000s, hard drives remain an affordable storage workhorse. Their mechanical moving parts make them unsuitable for portable devices like smartphones, but ideal for high capacity stationary storage.
Almost all modern servers, desktop PCs, and game consoles rely on internal HDDs as their primary long-term storage medium.
Reliability and Accessibility
Hard disk drives provide reliable and readily accessible storage. Because they are non-volatile (retain data without power) and random access (data can be accessed in any order) they have key advantages over sequential storage like tape.
Hard drives give operating systems, applications, and users a permanent storage location to call home. System files, programs, and personal data remains intact and quickly accessible between power cycles.
This reliability enables users to turn off their devices without worrying about losing data. It also enables backups, snapshots, hibernation, and virtual memory.
Cost Effectiveness
Even with declining prices, solid state drives are still more expensive per gigabyte than hard drives. As of 2020, 1TB hard drives provide the lowest cost per gigabyte for everyday bulk storage:
| Storage Medium | Cost Per GB |
| Hard Disk Drive | $0.02 – $0.05 |
| Solid State Drive | $0.10 – $0.20 |
This makes HDDs ideal for high capacity consumer storage needs like media libraries. In the enterprise, HDD arrays can achieve petabyte scale data warehouses on budget.
Hard drive mechanisms have also greatly improved over decades of refinements while retaining fundamental mechanical designs. This has maximized their cost efficiency.
Speed and Performance
Hard drives have traditionally traded some speed for their low cost and high capacity advantages. But modern HDDs have bridged much of the performance gap with SSDs by incorporating:
- Larger cache buffers
- Increased platter density (1TB+ per platter)
- Improved spindle speeds (10k+ RPM)
- Faster controllers and interfaces (SATA III, SAS)
For many consumer workloads, modern HDDs provide sufficient performance. Even lower RPM large capacity drives can sustain 100+ MB/s sequential speeds.
In servers, performance critical applications are often placed on SSDs, while hard drives provide economical bulk storage. Hybrid configurations are also popular, with hot data cached on an SSD tier.
Large Capacities
The highest capacity drives on the consumer market are mechanical hard disk drives, with models as high as 20TB now available. Enterprise drives reach into the dozens of terabytes.
This is made possible by continuing advances in areal density – the amount of data that can be stored on a single platter. Current technology allows over 1TB per square inch.
SSDs remain far behind HDDs in capacity. The largest single SSDs are around 100TB, while HDDs reach much higher total capacities through multi-drive arrays.
Evolving Usage
While HDDs remain essential in many use cases, solid state drives are taking over some areas formerly dominated by mechanical disks:
- Laptop primary storage – Faster, lighter SSDs allow for slimmer more portable laptops.
- High performance computing – SSDs provide far higher IOPS and throughput for speed critical tasks.
- General consumer use – Falling SSD prices make them viable for more basic everyday computing needs.
However, HDDs continue to be ideal for bulk data storage. Users with large media libraries will likely always need spacious and economical hard drives.
In the enterprise, nearline HDDs provide affordable scale-out bulk capacity. While all flash arrays have performance advantages, they do not match the petabyte scale possible with spinning disks.
The Future
Hard disk drive technology continues to evolve. Some future improvements may include:
- Larger capacities approaching 50TB+ in consumer drives
- Helium sealed drives, allowing for more platters and denser packaging
- Shingled Magnetic Recording, overlapping tracks for increased density
- Heat Assisted Magnetic Recording for greater density
- Faster spindle speeds up to 15k RPM
While SSDs continue to outpace HDDs in performance, hard drives still provide the most economical solution for mass capacity. HDD technology will evolve enough to ensure disks have a place in the storage hierarchy for the foreseeable future.
Conclusion
In summary, hard disk drives are primarily used any time large amounts of data need to be reliably stored in an affordable manner. This includes operating system installation, application storage, user file repositories, game installs, media collections, and enterprise data storage.
Mechanical hard drives continue to offer high capacities, decent performance, and very low per-gigabyte pricing. These factors ensure HDDs remain relevant in the computer storage landscape despite the rise of flash-based competitors.