In the early days of personal computing, a hard drive was an absolute necessity – there was no practical way to store programs or data without one. But with advances in technology, particularly flash-based solid state drives (SSDs), some have questioned whether the traditional spinning hard disk drive (HDD) is still a required component in a modern PC.
What is a hard drive?
A hard drive is a data storage device that uses magnetic storage to store and retrieve digital information. The earliest hard drives were developed in the 1950s for data storage on mainframe computers. The first model resembled a large drum that rotated at high speed with data recorded on the outside surface.
Modern hard drives still operate on the same basic principle but with rapidly spinning disks or platters coated in magnetic material instead of a drum. A read-write head on an arm accesses the data as the platters spin. Hard drives store data on the platters in small magnetized areas called sectors.
Because a mechanical arm has to move into position over the platters to access data, there is a delay before the data can be retrieved. This is known as the hard drive’s seek time and rotation latency. The advantage of a hard drive is that it can store very large amounts of data at a relatively low cost per gigabyte.
The rise of solid state drives
Solid state drives (SSDs) store data on flash memory chips rather than magnetic platters. Without any moving parts, SSDs have much faster data access times. Early SSDs were expensive and had limited storage capacity but this has rapidly improved over time.
A SATA III SSD can provide sequential read speeds over 500 MB/s, compared to around 100-200 MB/s for a traditional hard drive. Random access times are even faster – microseconds for SSDs rather than milliseconds for HDDs. SSDs are now available with multi-terabyte storage capacities that can rival hard drives.
With no moving parts, SSDs also offer other advantages. They operate silently, have lower power consumption, and better shock resistance for mobile computing. However, SSD costs per gigabyte remain higher than hard drives.
Uses for hard drives today
For general computing needs, SSDs have largely replaced hard drives for the primary storage volume where the operating system and applications are installed. The performance benefits of SSDs for boot times, launching programs, and opening files are too significant to ignore.
However, traditional hard drives can still be useful in a number of roles:
- Data storage and archives – HDDs offer more storage capacity for lower cost.
- External storage – External USB hard drives provide affordable storage expansion.
- Secondary internal storage – Systems may add a HDD as a secondary drive for data storage.
- Boot drives for older systems – HDDs can extend the usable lifespan for older PCs.
- Specific workloads – Some write-intensive server workloads still use HDDs.
For these applications, the advantages of SSD performance and resilience are less critical. The large capacity and low per-gigabyte cost of hard drives can make them a better solution where large storage needs outweigh the benefits of accessing data rapidly.
Drawbacks of relying solely on SSD storage
While SSD prices have dropped dramatically, HDDs still offer a significant cost advantage for high capacity storage needs. Let’s consider a scenario where a desktop computer has a 512GB SSD instead of a 256GB SSD paired with a 1TB hard drive:
- The 512GB SSD may carry a 50-100% price premium over a 256GB model.
- The user has less overall storage capacity available.
- Larger files like photos, videos, and games will quickly fill up the SSD.
- More time is required to manage storage by removing unused files.
- External drives may still be needed for backup.
By pairing a smaller SSD with a larger hard drive, total storage capacity is increased at a lower overall cost. Files that benefit from speed, like operating system and apps, reside on the SSD while bulky media files and backups use the HDD.
Is an HDD necessary for backups?
Backing up important data is vital to avoid loss should a computer fail or suffer data corruption. While external hard drives are commonly used for backup, there are alternatives that mean an internal HDD is not obligatory.
Options include:
- External SSD – More expensive per gigabyte but faster transfers and more resilience.
- USB flash drive – Small capacity but handy for incremental backups.
- Network attached storage (NAS) – Central storage on home network.
- Cloud storage – Online backup space from providers like Dropbox.
The right backup solution depends on budget, capacity needs, and whether the backup must be local. An external HDD no longer has a monopoly on providing redundant copies for backup.
Is a hard drive still needed for extra storage?
The falling prices of SSDs make them a viable option for both primary and secondary storage. Systems that need more capacity can add:
- A higher capacity SSD as the secondary drive.
- An external SSD connected via USB, Thunderbolt etc.
While HDDs have an advantage for bulk storage in terms of gigabytes per dollar, an SSD may be justified for secondary storage if transfer speed is important. For example, content creation working with large video files would benefit from the faster access speed of SSDs.
Should you still consider an HDD for older systems?
Older computers may not have an interface that can take advantage of the faster speeds of an SSD. In that case, replacing a hard drive with an SSD offers less benefit apart from ruggedness. It may be more cost-effective to continue using HDDs rather than replace aging systems.
Operating systems and software become more demanding over time. An old PC may struggle with a modern OS and apps even with an SSD. Hard drives can extend the functional lifespan of older machines by a few more years before upgrades become inevitable.
What about hard drives in servers?
In data centers, HDDs retain an advantage for certain server workloads. High capacity enterprise-class hard drives can provide huge amounts of inexpensive storage for archival data that is infrequently accessed. Big data applications like Facebook can utilize vast farms of HDDs for older posts and media.
Hard drives are also suitable for sequential write-intensive applications like log processing where data is appended continuously. The latest SATA and SAS hard drives can sustain over 200 MB/s for sequential writes.
However, databases and other enterprise apps utilizing random access patterns will benefit from the transition to solid state storage. Hybrid arrays with SSD caching tiers help combine responsive performance for frequently used data with HDD capacity.
Conclusion
At one time, hard drives were the only viable option for storage in a PC. Their mechanical limitations resulted in slow boot times and delays launching programs and accessing files. Today, SSDs have removed those bottlenecks and provide huge gains in system responsiveness.
For most home and office users, an SSD alone may meet storage needs. External drives, cloud storage, and other backup mediums mean hard drives are no longer obligatory for redundancy either. However, HDDs still serve a purpose where massive amounts of cheap storage are required.
While SSDs continue to fall in price, HDD technology has reached a point of diminishing returns. Hard drives can supplement an SSD as bulk storage in a desktop system or provide huge centralized capacity in data centers. But they are no longer an essential component just to have a functioning computer.
Summary
The key points on whether hard drives remain a necessary component are:
- SSDs have much faster access speeds and lower latency than HDDs.
- SSD prices have dropped substantially but HDDs retain a cost advantage per terabyte.
- For general computing, SSDs are now the default for the primary drive.
- HDDs are still useful for bulk data storage, archives, backups and some server tasks.
- Older systems may benefit from HDDs for boot drives due to interface limits.
- External SSDs, NAS, the cloud and other mediums can replace internal HDDs for backup storage.
- In specialized roles, HDDs still have a place and are not quite obsolete yet.
While no longer essential in all cases, the hard drive remains a relevant technology and will continue to have useful applications for the foreseeable future.