All You Should Know about External Hard Drives

By Connie | Posted to Home > Wiki, updated on June 9th, 2021

Summary: In this post, you will learn the definition of external hard drives, their types and usages, factors that need to be considered when choosing one, and our picks of the best external hard drives for Mac.

Hard Drive

Basic information about an external hard drive

Let's take a comprehensive learning of the external hard drive.

What is an external hard drive

Originally, the internal hard drive of your computer is the only storage space to save your data, but with the rapid development of the information era, it's far not enough. So, to satisfy your needs for storing extra data, the external hard drive came out.

Unlike the internal hard drive that's inside a computer, an external hard drive is connected to the computer from outside via USB, FireWire, or wirelessly. As one of the external storage devices like the common USB flash drive, the external hard drive is also portable and mobile.

What is an external hard drive
Source: Forbes.com

Usage of external hard drives

There are two main purposes for you to use external hard drives. One is expanding the capacity of your computer when the internal storage space is not sufficient. The other is backing up data of your computer in case of data loss due to internal hard disk corruption or hardware damage.

Besides, as the external hard drive is portable, it also enables data exchanging between computers locally.

Available Capacity

Usually, the storage space of an external hard drive is considerable. Unlike most USB flash drives are only a few dozens of GB, external hard drives in the market are commonly in 320GB, 500GB, 600GB, 640GB, 900GB, 1000GB (1TB), 1.5TB, 2TB, 2.5TB, 3TB, 3.5TB, 4TB, even up to 12TB capacity.

But there also have some relatively small storage external hard disks. Those are 1.8-inch external hard drives in 10GB, 20GB, 40GB, 60GB, or 80GB.

Data read and write speeds

External hard drives mainly have three interfaces: USB, FireWire (IEEE1394), eSATA. The data transmission speed of the external hard drive varies from the interface.

USB 2.0 theoretically supplies 60 MB/s bandwidth, but overhead typically reduces this to an effective 25 MB/s to 30 MB/s. For the USB 3.0, its nominal transfer rate is 625MB/s. And USB 3.1, released in 2013, has up to 1250 MB/s data transfer speed. For the later USB 3.2 released in 2017, with data rate up to 2500 MB/s.

USB 2.0 interface vs. USB 3.0 interface

And the IEEE1394 interface transfer speed is 50~100MB/s. When it comes to eSATA, it can achieve such as SATA 1.5Gb/s or SATA 3Gb/s transfer speed.

IEEE 1394 interface vs. e-SATA interface

In general terms, it only takes seconds (or less) to minutes to read and write the data, of course, according to the sizes of data units.

Common external hard drive types, file systems, and brands

Generally, there two types of external hard drives, which are hard disk drives and solid-state drives. Hard drive disks (HDDs) are traditional hard disks which mainly rely on spinning magnetic disks or platters to read and write data, while solid-state drives (SSDs) use tiny gate transistors in cells that flip on or off based on electric pulses.

The most common file systems formatted in external hard drives include NTFS, APFS, exFAT, FAT, HFS Standard, or HFS Plus.

Nowadays, most HDDs and SSDs are manufactured by Samsung, Western Digital, Toshiba, Seagate, Hitachi (HGST), SanDisk, Kingston Technology, Transcend, etc. Among them, Samsung (33.6%), Western Digital(24.6%), and Seagate(15.7%) has taken up the most market share by the end of 2019.

Guide to select an external hard drive

To choose an external hard drive, we also conclude some useful tips for you.

  1. Price. According to blocksandfiles, the cost per Terabyte for a regular 2.5-inch or 3.5-inch HDD is $21 on average in 2021 while that for SSDs will be $86. But the pricing difference is shrinking continuously between HDDs and SDDs.
  2. Capacity. For the long term, an external hard drive with over 1TB capacity is better.
  3. Compatibility. Choose an external hard drive with the file system that is compatible with your operating system. If you are a cross-platform user, select an external hard drive with universal FAT or exFAT. If you have an NTFS disk which is previously formatted for Windows, you can use iBoysoft NTFS for Mac to read and write NTFS files on Mac.

Note: If you get an external hard drive with a file system that's not compatible with your machine, you can format the external hard drive.

How to format an external hard drive on Mac

How to reformat an external hard drive on Windows

  1. Reliability. It is never wrong to choose an external disk from a well-known company because they usually have high and stable quality standards. With good maintenance, SSDs has a longer life cycle (up to 10 years) than HDDs (3-5 years).
  2. Data transfer speed. Generally speaking, SSDs have faster data transfer speed than traditional HDDs. Connection interface matters too. The external hard drives with an eSATA interface have the highest data read-write performance. If you only have USB ports on your computer, it makes sense to choose an external hard drive with Thunderbolt, USB-C, or at last USB 3.1/3.0 connection.

The best external hard drive for Mac

Since Windows still take most of the market share in computer operating system, there is no doubt that most portable hard drives are manufactured mainly for Windows platform. How to select an external hard drive for Mac then?

After research, we pick up two disks for you.

1. WD My Passport for Mac 2TB ($69.99)

This WD external hard drive is cost-effective and has 3-year warranty. Having USB 3.2 interface, it offers the fast data transfer speed to improve your work efficiency. Moreover, WD My Passport for Mac pairs with Apple's Time Machine backup software.

WD My Passport for Mac 2TB
Source: Westerndigital.com

How to fix My Passport for Mac hard drive not mounting

How to fix WD My Passport not showing up or working on Mac

2. Seagate Backup Plus Ultra Touch HDD 2TB ($79.54)

With small and light design, this external hard drive provides handy backup/recover functions. By default, this Seagate drive comes formatted in the exFAT file system which is compatible with Mac OS.

Seagate Backup Plus Ultra Touch HDD 2TB
Source: seagate.com

2. Samsung T5 SSD ($119.99 - $239.99)

This Samsung SSD external hard drive is up to 2TB and is very portable. With USB 3.0 interface, this drive is suitable for most Mac machines and have a fast data tansfer speed than USB 2.0. It also comes with encryption feature and has a 3-year warranty.

Samsung T5 SSD
Source: SumSung.com

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