Backups, family archives, and simply transferring files from one computer to another can all be done with something as small as an external hard drive. Representing an internally complete analogue of a conventional hard drive, an external hard drive differs only in that it is placed in a special box that allows you to connect it directly to the device connectors.
What to look for when choosing an external hard drive?
Before you make a purchase of an external hard drive, you need to choose a model with the necessary parameters, so you first need to decide on the goals of its further operation. How many files should fit on the disk, and what type they will be, whether its appearance and mobility are important — all these factors determine the need for memory, speed and dimensions of the hard drive.

Dimensions and weight
External hard drives are measured in inches and can have one of two standard sizes: 2.5 and 3.5 inches. The first option is more mobile. Hard drives of this size weigh just over 150 grams and can be easily folded into a handbag or even a pocket. 2.5-inch drives are characterized by low power consumption and the ability to work from a standard USB port. In connection, hard drives of this form factor are the most common.
3.5-inch hard drives are most often used to work on a desktop computer. Due to their hefty weight, which can reach one and a half kilograms, and the requirement for an additional power supply, such hard drives are too bulky to carry in a simple purse. They are best suited for creating archives, multimedia libraries and family photo albums.
Memory type
In modern portable hard drives, one of the types of memory can be implemented:
- HDD — on hard magnetic disks,
- SSD — solid state,
- SSHD — solid state hybrid.
Due to their low cost, HDD drives are the main type of drives. However, their sensitivity to drops, shaking and other mechanical impacts is becoming a major drawback, which is gradually forcing them to give way to more modern solid-state and hybrid drives.
The SSD drive does not contain moving parts, so this type of memory is resistant to mechanical stress. In addition, it is characterized by lower power consumption and more compact size. Despite these significant advantages, solid state drives are limited in use, since the maximum number of rewrite cycles is 100 thousand times. An SSHD drive allows you to avoid the disadvantages of the latter type, which places frequently used data in the solid state part, and the rest in the magnetic disk zone.
Selecting the size of the hard disk
Special attention should be paid to the choice of hard drive size. More mobile 2.5″ drives are usually limited to 500 GB. While larger 3.5-inch ones can contain over several terabytes of information. Based on this, the selection of volume will depend on the purpose for which the disc is purchased.
If you need a device for the constant transfer of information of this type, such as electronic documents, photographs, saved web pages, and the like, then you can limit yourself to small volumes from 250 to 500 GB.
To store an entire collection of movies and family videos, which are known to take up a lot of storage space, it is better not to limit yourself to a few hundred gigabytes, but to buy a hard drive with at least a few terabytes. Then you don’t have to look for a place on the disk for the next recording or erase unnecessary files.

Selecting a hard drive interface
How fast an external hard drive will read and write information depends on its interface. This parameter is important for full-fledged work with the device, so it should also be given its attention.
Today there are several interfaces:
- USB 2.0 is the most common option with a maximum transfer rate of 480 Mb/s,
- USB 3.0 — standard with a speed of 4.8 Gb / s,
- eSATA is a less common standard with a speed of 3 Gb / s,
- FireWire is a rare option that allows you to transfer information at speeds up to 1.6 Gb / s,
- Tunderbolt is Apple’s standard for 10 Gb/s speeds.
- Wi-Fi is a wireless technology for transmitting information at speeds up to 450 Mbps (Wi-Fi ac — at speeds up to 6 Gbps).
Although USB 2.0 is still considered the most popular interface, the obvious speed advantages of its more modern version are becoming an important factor in making USB 3.0 the rank of the most current technology. The rest of the interfaces are less common and limited by the brand.
In addition to the interface, the speed of reading information is influenced by the speed of rotation of the spindle. For 2.5-inch hard drives, this indicator is lower than for 3.5-inch ones, so the speed of finding information will be the highest for 3.5″ drives operating on the USB3.0 interface.
Before choosing USB3.0 technology, you need to make sure that the device to connect to which you purchase the hard drive has this port. Otherwise, there will simply be no benefit from buying a more sophisticated disk model, so you need to limit yourself to version 2.0.

Expert advice
In addition to the main parameters of external hard drives, there are factors that will not be obvious during the selection and purchase process, but may adversely affect the operation of the drive.
Operating system compatibility
Operating system compatibility issues can prevent the external device and computer from working together. A hardware conflict can occur if a hard drive with a more modern NTFS is connected to a computer with a FAT 32 file system. In this case, the computer simply does not determine what is written on the disk.
Hard drives with the FAT 32 file system will work fine with various operating systems, even older ones, but will not support writing files larger than 4 GB, which is not suitable for most multimedia files. Therefore, if you need to record movies and high-quality music, then the hard drive must have a FAT 32 file system.
Software
Improving the protection of information and reducing the power consumption of the hard drive is achieved by using additional programs that are often included with the device. These programs allow you to create regular backups of all information on the drive, as well as turn off hard drives after a certain period of inactivity, starting it up at the first access.
The convenience of such programs allows you to significantly expand the capabilities of external drives, so do not neglect their use. Each disk has its own set of such programs and depends on the manufacturer.
If you still have questions about how to choose an external hard drive, ask them in the comments.