Hard drives provide storage space for computers, laptops and more. In this blog post we will explain what hard drives do, describe types of hard drives, and finally teach how to choose the right hard drive when purchasing or upgrading a computer.

As usual, we won’t get too technical: our posts are meant to be understood by users of any proficiency.

What Hard Drives Do

If this breaks, your data is toast.
If this breaks, your data is toast.

Simply put, hard drives provide non-volatile (persistent) storage of data. Non-volatile means when the computer turns off, the data is still there when it’s turned back on.  Your operating system, your files, your entire computer experience is the result of data stored on your hard drive. Storage space is measured in gigabytes (GB). It is common to find hard drives in sizes of 64GB to 1000GB (1 terabyte, or TB).

Types of Hard Drives

Hard drives are generally categorized by the mechanism used to store and access data.


Parts of a hard disk drive
Parts of a hard disk drive

Traditional, or hard disk drives (HDDs), use a spinning platter to store and read data. The best way to describe a hard disk drive is to consider an older record player with a needle and a spinning platter. Just as the needle “reads” the surface of a record and turns that data to music, a hard disk has data etched into it’s surface and read by it’s needle.

The rate the platter spins, rotations per minute (RPM), determine how fast data can be accessed. Speeds of 5400 and 7200 RPM are common. Higher RPM are generally considered higher performance.


  • Relatively inexpensive (in terms of price per GB)
  • Large storage space (available in sizes greater than 1TB)
  • Last long


  • Moving parts use power, draining laptops faster than a solid-state drive.
  • Slower data access speeds because of moving parts
  • Susceptible to fragmentation

Solid State

Comparison of drive technologies
Comparison of drive technologies

While a HDD uses a spinning platter and moving parts, a solid-state drive (SSD) uses integrated circuits (“flash” storage). This means data is written and read much faster. The lack of a motor also means SSDs use less power in laptops than their spinning counterparts. Solid-state drives are considered higher performance and are generally found in higher-end computers.


  • Fastest data access (read/write) speeds
  • Lowest power consumption
  • Not susceptible to fragmentation


  • More expensive than traditional drives
  • Generally has shorter longevity than traditional drives
  • Difficult to recover data if they fail


There are drives that attempt to provide the best of both traditional and solid-state drives by combining the inexpensive storage of a platter with the high speed of an integrated circuit. On a solid-state hybrid drive (SSHD), a few GBs of flash storage allow fast access to the operating system and frequently used programs. This provides performance similar to SSDs.

However, a platter provides several hundred GBs of storage for files such as documents, photos and videos, which don’t necessarily need the breakneck speed of solid-state storage.


  • More storage space than SSD
  • Not as expensive as a SSD


  • More power consumption than a SSD
  • Not as fast as SSD


External hard drives are great for backing up data.
External hard drives are great for backing up data.

External hard drives provide additional storage to computers and compatible devices when you can’t (or don’t need to) permanently add internal storage. External drives are frequently used to save backups or transfer large files between computers. View our data backup/recovery services.

Buying a Hard Drive

Whether you are buying a new computer, or upgrading your current computer’s storage capacity, you will want to know a few things about hard drives to make a smart purchase. View our installation and upgrade services.

Physical Size

This is more important for someone performing an upgrade than for someone buying a new computer. Laptops use a 2.5″ drive. Most tower desktops use 3.5″ drives.

Storage Size

If more than 500GB of space is desired, go for a HDD. SSD storage has increased over the years while the prices lowered, but is still more expensive than HDD storage.

Connector Type

There are two major interfaces: SATA, which is most common, and IDE, which is usually found in older computers. When upgrading a hard drive, make sure the drive’s connector type (SATA II, SATA III, or even IDE) is compatible with the motherboard.

Storage Type

HDD, SSD or SSHD. For the best performance possible, we recommend going for a SSD.


We hope this brief guide explained the mysteries for the hard drive. Stay tuned for more posts about common computer parts.

Shopping for a new hard drive? Check out the Amazon for the best prices. 

Have a question about purchasing a new computer, backing up your data, or upgrading your current system? Feel free to comment below, or contact us to schedule an appointment!

Published by Kamryn

I.T. Consultant & digital wizard