Introduction to External Hard Drives

The Basics

What is an External Hard Drive?

You're probably aware that your computer has memory, or at the very least that you're able to save your various files and documents on the computer and then go back and retrieve them later. All that information that you save to your computer is saved into a hard drive of some sort. We often refer to hard drives as a form of data storage. An external hard drive is essentially just a portable data storage system. Without going into the intricate details of memory, simply know that an external hard drive allows you to save information and documents to a small portable device that you can remove from one computer and bring to another, allowing you to easily transfer that saved information and back it up. For more information about formatting hard drives, see this article.


Why would someone need one?

Here at Hamilton, if you are taking a video class you will be required to have an external hard drive of your own. This is because the video files you will be working with are too large to be stored in the student storage server the school provides, and you will want to be able to work on your projects on different computers as well as have them backed up. Students who are not taking a video class may still find it useful to have an external hard drive for the reasons mentioned earlier. Basically, purchasing an external hard drive will provide convenience and security for one's data.



Purchasing an external hard drive is a great way to back up important files and keep all of your work in one central location. Think of it as a portfolio of your work! When purchasing a drive, there are some technical details to consider.



While USB ports are found on all computers, there are many versions and some can be slow to transfer large files (think video files). Firewire and Thunderbolt ports are faster, but might only be available on Apple hardware. Look for a drive that has multiple types of connection ports.


If you're buying an external drive, portability is important. Some drives can be powered right through their connection port, which means you don't need to carry the "wall wart" power cable. Also consider the size of the case. Small drives are easy to carry


Hard drives are delicate and a big bump can destroy the drive and your data. Look for a drive that rugged enough to stand up to trips in your backpack to the computer lab.


Bigger is better, but for the same price point you'll trade features for capacity. Video is the one medium that quickly eats up your hard drive space. If you plan on taking a class that uses video, think big... 500GB should do.



The platform which you intend to use your external hard drive with will determine the formatting that is required for it. The resource center contains pages explaining ways to format your external hard drive for all of your possible needs, but in this section is some information as to what the different formats are and what they are for.

The Formats

FAT32 (File Allocation Table)
  • Natively read/write FAT32 on Windows and Mac OS.
  • Maximum file size: 4GB
NTFS (Windows NT File System)
  • Natively read/write NTFS on Windows.
  • Maximum file size: 16TB
HFS+ (Hierarchical File system, aka Mac OS Extended)
  • Natively read/write HFS+ on Mac OS.
  • Required for Time Machine
  • Maximum file size: 8EiB  ( Note: More than large enough for any file in the modern world.)


How do the Formats affect you?

You will need to select the correct format for the platform you intend on using your external hard drive with. If you are primarily a PC user who will not need to transfer files on a Mac, then NTFS is the format for you, and luckily for you most external hard drives are sold already formatted as NTFS. If you are primarily a Mac user who will not need to transfer files on a PC, then you would choose HFS+ (Mac OS extended). If you are a user who will have to transfer files across both platforms, then life becomes a bit more complicated. The information about the formats above may lead you to assume that you would simply format as FAT32, since it can read/write on Windows and Mac OS, however this is not a good idea for the following reasons.

  • FAT32 offers no security
  • FAT32 has a max file size of 4GB. This is an issue if you are a video student where you will likely deal with files larger than this.
  • FAT32 is overall a less efficient and reliable format.

So what does a user who needs to transfer across platforms do? There are a few solutions, but the one we suggest and provide directions to here at Hamilton is to partition your external hard drive into 3 partitions, and format each partition as a different Format. This will allow the user to read/write files on both platforms, and also transfer files under 4GB in size from either platform.

So how does someone format an External Hard Drive?

Directions on how to perform all of the above formatting have been included in the ITS Resource Center. The links are included below.

Formatting for Primarily PC Users

Formatting for Primarily Mac Users

Formatting for Users working with Both Platforms


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