What is an external hard drive?

A hard drive is a computer part that stores data. Music, videos, and any such files are data. External hard drives are used with internal hard drives to hold more data and to make the data portable. You can securely store data on an external hard disk and keep it safe.

Let’s say you have a lot of media and it must be stored somewhere and carry it often. Here is where external hard disks fit in.

Why do you need an external hard disk?

I say leaving all your precious contents to computer without a backup is a bad idea. Therefore backup is a must if you are not ready to lose your data.

Portability is another important factor. You may want to copy files from your friend’s computer, say some really big files like games or lots of movies; you need an external hard disk.

Types of external hard disks

There are 3 types of external hard disks.

  • Desktop hard disk
  • Pocket hard disk also called portable hard disk
  • Solid Sate Drive (SSD)
How to Buy an External Hard Drive - 7 Factors to Consider 13
How to Buy an External Hard Drive - 7 Factors to Consider 14

Desktop Hard Disk

It usually consists of a 3.5-inch spinning disk mechanism and requires an external power supply to run. It must be placed near the computer and is connected via USB cable. The 3.5 inch has a maximum capacity of 4 TB. All desktop hard drives come with a cooling fan to increase the life.

Another category of desktop hard drives is multiple external hard disks which contain 2 or more hard disks in 1 case. It is also called RAIDs (Redundant Array of Independent Disks). The advantages of RAIDs are:

  • Increased storage space
  • Increased speed
  • Increased protection

Disadvantages are:

  • Increased complexity
  • Increased price

There are several levels of RAIDs like 0,1,2,3 … For the great protection of data; you should choose 1, 5 or 10. Other levels have great speed, capacity etc… The attributes vary with levels.

Pocket or Portable Hard Disks

Unlike desktop HDD, they can be carried around. They have 1.8 inches or 2.5-inch spinning disk mechanism. The main advantage is that it requires no power adapter.

Solid State Drive (SSD)

They have no moving parts like ‘spinning disk mechanism’. Therefore has a very high data transfer speed with USB 3.0 or above. They are commonly used in notebooks because their size is small compared to other HDDs. They also have a very good shock resistance. But they are slower when plugged into a USB 2.0 port. They are not so popular because of the high price. SSD’s are 3 times costlier than HDD’s of the same capacity.

How to Buy an External Hard Drive - 7 Factors to Consider 15


Searching for the best portable hard drive? Here is the list of best 15 hard drives compared with specs and key features. Choose the best of everything…

How to Buy an External Hard Drive - 7 Factors to Consider 16

Factors to Be Considered When Buying an External Hard Disk


A hard drive consists of a spinning disk mechanism. The speed of the hard disk is the speed of spinning measured in r.p.m(revolutions per minute).

Usually, hard disks have an r.p.m of 5400 or 7200. But there are hard disks with larger as 10000 r.p.m.

To conclude, as r.p.m increases copying speed also increases. Those who work with large files such as video editing or graphics related works should consider buying high r.p.m disks.


Hard disks are connected to the computer via USB cable. The copying speed also depends on the type of connecting port. USB 2.0 works with lower r.p.m while USB 3.0 works with high r.p.m. Therefore USB 2.0 is much slower. It supports a maximum transfer speed of 60MB per sec while USB 3.0 supports 600MB per sec. We can see the 3.0 is 10 times faster than 2.0.


Most of the hard disks have a capacity between 120GB and 4TB. Choose one that fits your need. For personal use, to store movies, music, and games, 1TB will be enough. But for those who work with larger files (graphic designers, game developers, video editors) need to store them securely and will have to purchase a hard disk with larger storage space.


When it comes to hard drives, the brand is an important factor. You must not lose your precious data believing in some local brands for the sake of money. It is always safe to buy from a reputed and well-known manufacturer. Some of the trusted brands are




Western Digital


G Technology

Buffalo etc…

Another thing is that external hard disks get damaged easily. Many HDDs suddenly fail without any reason. Therefore it is better to buy an HDD with at least 2-year warranty.


Desktop HDDs require the power supply to work with and are not portable. Since they consist of moving parts, portability is a real issue. Hard disks can wear out easily due to the shaking and rattling caused by travel. If you travel a lot, and your hard disk is a companion throughout, look for rugged hard disks. Rugged hard disks will withstand most of the shocks. If your hard disk does not ‘travel’ a lot, there is no point in wasting some more money on rugged hard disks.


Nowadays, external hard disks come with a password protection option which is very useful in protecting the data from theft. Hard disks with advanced protection like fingerprint recognition will be more expensive.

Physical Size

As explained above, there are two types of HDDs classified according to the physical size. 3.5 inch is the desktop type and need cooling fans and thus more space. 2.5 inch is the portable type and is best for travel purposes.

To conclude…

Change is inevitable and HDDs will also be subjected to change. Capacity and speed will increase, new technologies will be introduced. What we can do is to buy the best available in the market.

Check out 7 Best Portable HDDs from Cheap to Top Class

Check out 11 Best HDDs For Photographers – Desktop Portable & Wireless

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