The Part About Hard Drives You Need To Know.
DECIDING HOW MUCH DRIVE STORAGE YOU NEED IS ONLY PART OF IT
A while back, after my son went off to college, he called me one day full of pride at his troubleshooting skills. On a road trip he’d seen that his friend’s rear tire was going flat and their attempts to fill it just ended up letting out more air. But in the end - thanks to YouTube - he had figured out how to use the service station air pump and got the tire fully inflated again.
As much as I loved his ingenuity, I was also embarrassed that I hadn’t done my Dad thing and at some point had showed him how to fill a tire. It was a lesson in humility. Sometimes you just assume that basic stuff is universally understood. That everyone gets it. But it’s not.
Watching some YouTube videos the other day reminded me of that experience. I’ve certainly found a lot of good advice on YouTube myself, but on the subject of digital storage, I was impressed by how confusing or imprecise it could be. These days we all have to use external drives and a crucial part of the process slid under the radar of most videos I saw. The crucial ingredient for success; choosing the right format.
Sooner or later you will need to move, copy, or archive files off your primary device - Mac, iPad, or iPhone - to a separate storage device. A hard drive or solid state drive. Fortunately, hard drive technology is so mature that you can expect good, reliable performance from any of the top brands. Your decision will be mostly based on cost, connection type, and features.
But often installing a new drive involves changing the format of that drive to ensure it works properly with the Apple ecosystem. You’ll need a Mac to do this.
You can think of drive formatting as the base language of the drive. With the proper formatting, the Operating System can read and write data in a familiar language that takes advantage of the features and efficiency of that language. Other formats may be somewhat readable, with translations, or so foreign as to not be readable at all. Drive formatting also determines file limitations; like the allowed length and characters of file names, maximum size of saved files, security features, and whether there are safeguards against file loss. Proper drive formatting for the Operating System you use is a wise precaution against data loss, performance issues, and file compatibility.
Here are the most common drive formatting options:
Mac OS Extended - Also called HFS+, the longtime standard for spinning Hard Disk Drives (HDD) that offers the most efficiency, security, and compatibility with the macOS and apps for the Mac.
APFS - Apple’s new file format for Solid State Drives (SSD) that includes advanced file management and security. It can be used on HDD’s too, but won’t offer the same performance as HFS+ on HDD’s when less than 20% of storage space remains. APFS is the default format for Time Machine drives.
NTFS - The preferred drive format for Windows PC’s. NTFS drives are readable on the Mac but cannot be written to without 3rd party software.
ExFat - Compatible with both Macs and Windows. Commonly used with thumb/flash drives with over 32GB storage capacity. Not suitable for archiving or as an active external volume.
FAT32 - Compatible with both Macs and Windows. 4GB max file size. Commonly used with thumb/flash drives with less than 32GB storage capacity. REALLY not suitable for archiving or as an active external volume.
The worldwide installed base of Windows PC’s is about 3 times that of Apple Macs, so hard drive and solid state drive sales are skewed heavily to PC compatibility by drive manufacturers. It’s important to read the fine print if you want to find a drive pre-formatted for Mac. Also, some drives will claim to be “Mac compatible” when they mean it can be re-formatted for Mac. Or, more and more, drives will be formatted as ExFat which is read and writable for both Mac and Windows but is not suitable for secure long-term storage or as an active external drive. ExFat is suitable for the temporary transfer of files between other devices and platforms but not much more.
Fortunately, you can head off issues with a quick check of any HDD, SDD, or thumb drive by using the Get Info panel on your Mac.
When you plug in your drive to the Mac, one of 3 things will happen.
You will get a pop up asking if you want to use the drive as a Time Machine backup.
You may get an error message saying that the drive is unreadable and asked if you want to format it.
The drive will just mount and show up on your Desktop and/or your Finder Window.
If you want to set up a new Time Machine backup drive, you can say yes to Door Number One and the macOS will automatically erase and reformat the drive as an APFS drive (on either HDD or SSD devices) and start backing up. If you say no, then you’ll be presented with Option 2 and go to Disk Utility to manually format it, or to Option 3 where it just mounts and shows up as a readable drive on your Mac.
In that last case, to find out what you’ve got, you can select the drive (single click) and in the Finder Menu Bar choose File > Get Info. In the Information window that pops up, you will see the format of the drive.
Usually, a brand new drive will offer you choices of #1 or #2. Having a drive mount up without a message generally means that it’s already been formatted and used for file storage or transfers. In which case you should open it up in the Finder to see what files it holds and whether you want to keep them.
It’s also important to note that reformatting any drive will erase all the data that’s already on there. Not a big deal if the drive holds files as leftovers from a file transfer from one computer to another, but a very big deal if it holds the only copy of a file you want to keep. I’ve seen plenty of extra hard drives that someone used as a “slush pile” of random files, documents, photos, and home videos that they just wanted to get off of their computer. But they didn’t intend to delete them altogether. If you are in that boat, be sure to clearly label what’s on the drive and how important they are when you move files to it.
And here’s why understanding drive formatting is a big deal. Hardly a day goes by without seeing a post about how to expand storage for a Mac or other device.
Storage space is becoming an issue for us all. Particularly those who are active photographers and videographers. Cloud storage is convenient but expensive. For some or all of our file storage physical drives are an essential part of our photo management. It may be for active storage, networked access, or long-term archiving, but we will all be buying more of them for all kinds of tasks. Whether we format it ourselves or instruct others to do it for us, knowing how to care for our data on the devices we have has become the 21st century equivalent of properly inflated tires and a regular oil change.
So keep in mind that the drive format is just as important to the safety of your precious photos as the physical drive is. Be sure that your formatting is appropriate for both your immediate and your long term tasks for that drive.
If you want more information about how to format your new or old drive you can reach out to me or check the Apple support site about using Disk Utility.
https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/mac
Solid guide here. The distinction between APFS on SSDs vs HFS+ on HDDs when storage is low is something I've seen trip people up in practice. I had a client once who couldn't figure out why their Time Machine backups were slow untill we realized they were using an SSD formatted as HFS+ instead of APFS. Switching the format cut backup times almost in half, which is a huge deal when you're doing weekly full backups of large photo libraries.
Paul, thank you for putting this summary of the disc formats together. It gave me the incentive to check the SSD drive on my MacBook, the two SSD external drives, and the external HDD. I found that all of the drives are formatted APFS, except one of the external SSDs is labeled APFS (case sensitive). Not sure how I formatted it that way but I’ll be backing it up and getting rid of that qualifier. Without your article I never would have noticed that. Thank you. Todd