Transcript
Micah Sargent (0:00)
Coming up on Hands on Mac, let's take a look at a way to reclaim disk space without getting rid of any of your files. Stay tuned. Podcasts you love from people you trust.
Leo Laporte (0:16)
This is Twit.
Micah Sargent (0:26)
Welcome back to Hands on Mac. I am Micah Sargent, and today we are taking a look at a really cool app that will help you reclaim disk space on your Mac. And this isn't your classic Mac app where you are like a cleaning app where you're looking through the different files that you have and you're sorting to find the largest files and seeing if you still need those or the ones that haven't been modified in a long time. No, instead, this is going to make use of an interesting quirk or feature, depending on how you see it in Mac macOS that gives the ability for the operating system to kind of refer to the same file in different places at the same time. So before we can actually take a look at the app, which I'm going to go ahead and tell you is called Hyperspace, I want to tell you a little bit about how the macOS file system actually works. The macOS file system default file system, I should say is APFS, Apple protected file System. And one of the features of this operating system, or rather file system, is to create multiple versions of the same file without creating multiple files. So it's kind of hard to understand. And the way that I want to explain this is by thinking about you being a person and waking up in the morning and putting on an outfit. Okay, maybe you wear pajamas to bed. You wake up in the morning, you switch out of those pajamas into what you're going to wear for the day. You underneath that are still you. But you in pajamas looks one way and you in your morning attire look another way, right? But you beneath those things is still the same. Think of the thing beneath the clothes as data. This is the information that makes up the base file. You, in this case, in this metaphor that we're doing, and the clothes that you are putting on that kind of refer to you with some changes. That's metadata. That's the stuff that is happening to you, right? That's the thing that's being changed about you by putting on clothes. The same thing sort of applies to files in macOS in the sense that you have a base file that is the data, and then the changes that get made to that file or to that data, rather is called metadata. That's the idea that it's referring to the base data and making changes to it. So in a sort of other file system, I should say, I could say a classic file system, but there are some instances where that's not the case in other file systems. What happens when you put clothes on the file, whenever you add that metadata is the operating system will create a new file for it. So you will have Micah in pajamas, Micah wearing a coat, Mica in shorts, right? And each of those is each its own file and its own bit of data with metadata added on top. So that ends up adding up to a lot of information that's getting stored on your disk. What APFS does, what Apple Protected File System does, is it says, look, I know that's mica underneath there. So I really only need secretly, behind the scenes, without us realizing as users, one version of Mica and then each of the files that we're creating, Mica in pajamas, Micah in a coat, and Micah wearing shorts. It's just the part of the data, a very much smaller part, the metadata that says, here's how that file has changed. So it's just the pajamas, it's just the shorts, it's just the coat. But whenever we go to access that, the file system refers to that metadata and adds it to that file, that data itself, to create the file. I keep saying file, but really we want to think about it as data and metadata together they make the file. So then you get Mica with shorts, Micah with a coat, Micah in pajamas, without needing to have three different micas, just one of them, because I am just one. Right? And that's all that it takes. So if you've had your system for a long time, if you've had your Mac for a long time, so you come from a time when Apple Protected File System wasn't part of what you've done, what you're using, or if you are using kind of mixed systems where maybe occasionally you work with Windows or There are a bunch of different reasons why Apple Protected file system on your Mac might not be doing that proper clever behind the scenes feature of making one bit of data and tying it to these different metadata versions, thereby getting rid of all that extra stuff. And so as you go forth, as you continue to make things, once APFS is set up, then it's not going to be an issue because in almost every case it will use this method. So what does one do if one wants to reclaim space on one's machine making use of this very cool feature of apfs? Well, one uses a little app called Hyperspace that you can get in the App Store. This app is a really cool app that is created by hypercritical and it lets you look at the files on your system and find those instances where we can instead of having three different micas, we compress it down to one and just have the metadata that is linked in multiple places. So let's take a look at what this is like on the Mac listeners.