What Is The Apple File System (APFS) Introduced In iOS 10.3

File Systems are how hard drives organize data for the operating system to read. Every operating system is built to work on a file system. Windows FAT, FAT32, and NTFS. macOS uses HFS+. Apple has been operating on the Hierarchical File System (HFS) for over 30 years. At WWDC 2016 Apple announced they were going to upgrade this system. They introduced the world to the idea of Apple File System (APFS). The latest iOS 10.3 which was rolled out just days ago brings this new file system to iOS devices. Here is everything you need to know about APFS.

Why Change to APFS?

You might ask the question, why move on to a new file system when a perfectly serviceable one already existed? Operating systems can address only a limited amount of space, i.e. what date range is available, and a maximum filename length, etc.. The problem with HFS  is that it came out in 1985. Back then, the largest amount of data anyone was dealing with was a few megabytes at best. So the file system was optimized for that amount of space. It could accommodate a date range of 1904 to 2040 and address 2 TeraBytes of space as well. That was astronomical back in 1985, it is barely par for the course today. Apple saw HFS’ impending doom and improved it a little with a 1998 update called HFS+ for their OS 8.1.

Today, however, not only have storage capacities evolved, so has speed. With the advent of SSDs and its evolution (M2 SSD for example), even the upgraded file system falls short. If we are accessing lightning fast drives using methodologies devised for 20 year old computers, there are bound to be issues. To overcome those issues, Apple is introducing the APFS. A closed source file system for all devices, iPhone, iPad, iPod, Watch, Mac, etc. It is primarily designed to better utilize SSD and flash storage (as commonly used today) as well as increase security and block jailbreaks.

How to switch to APFS?

Apple will switch users to the new system via an OS update. You really won’t have to do anything other than upgrade your OS. iPhone and iPad users who have upgraded to iOS 10.3 have already switched to the new file system. macOS users running the release version of OS will have to wait a little longer. Those on the beta version of macOS have already been upgraded to APFS.

What’s good about APFS?

Now that Apple have a bespoke file system, APFS will allow for a unified code base and fewer resources required for development making it even easier to maintain. Your devices will also run faster on this new file system. This is possibly the only major change end users will notice after the upgrade.

APFS also stores files more efficiently and so, after the upgrade, you might notice a little more free space on your device. It may or may not be substantial. Some users might not see much of a difference at all. What most will notice is that the device works better. Once APFS is available for macOS, users will be able to observe how much faster files copy.

What Makes APFS Faster?

A computer’s understanding of speed is much different from a user’s. For example, a system takes a set amount of time to boot up. Some users might consider it fast if their icons and wallpaper within 5 seconds of pressing the power button (even if there are items loading in the background), while some users might consider it fast to copy large files quicker. Speed is relative and a matter of perception as far as humans are concerned.

APFS is designed to give you the illusion of speed. For example, the APFS prides itself on low-latency. Which means it prioritizes app launches and data delivery. You won’t see a waiting spinner or beach ball as frequently anymore. 

Is APFS better suited for SSD?

Even though people think of SSDs as a recent phenomenon, they aren’t. In the 70’s they were called EAROMs (Electrically Alterable Read-Only Memory) and the first commercially sold SSD was called Bulk Core, in 1976! However, back then, as was the case with all processors and RAM, accessing anything electronically was slow. This would be the case for over 3 decades. So even though the technology existed, it was not treated as a priority.

Today, most of Apple’s current gen platforms (with the exception of some Mac Pros) operate with a variant of Solid State Storage, ‘Flash Storage’ chips. These are embedded on to the boards. This keeps the eco-system condensed (it is part of how they achieved the slim Macbook Air years before any competitor) and APFS optimizes how this storage is addressed.

For example, APFS supports TRIM command, which came about when SSDs went mainstream. TRIM tells the host operating system which parts of the drive are null i.e. no longer have data on them. With SSDs, this is instantaneous. So people who like keeping free space, will be able to acquire it as quickly as they can click ‘Delete’.

What’s Unique about APFS?

Another touted feature of APFS has been snapshot and cloning. The traditional methodology of copying from one source onto another has been to store items in a temporary location, and then copying those onto the target storage. This is to prevent damage/data loss on either side in case something goes wrong.

In APFS, Snapshots create a read-only version of the entire system one time. This means, it is just a copy of the original data, but it does not occupy any physical space. If you make changes to your original, the snapshot will take space to store it. This helps in retrieving any original copies or reverting any changes you might want made. Similarly, when you create a Clone, you keep a space-efficient copy of your entire system (real files, folders and all). It will also start occupying space as you make changes. This makes storage a very time-efficient endeavour.

For MacOS users who rely on partitions. APFS basically creates a container around all partitions instead of doing something permanent. This comes in handy when you run out of space on one partition and have ample left over in another. You can simple borrow space from another partition whether or not it is physically adjacent to the partition (SSDs render the need for proximity in storage obsolete anyway).

Legacy File Systems usually make room for a file before actually copying it. APFS supports sparse files, which basically use up only the amount of space as is physically taken up.

How safe is APFS?

With APFS, what used to be hard disk level encryption on macOS and file level encryption on iOS is now modified into system wide encryption operated under a consistent single-key and multi-key implementation. An example of a single key encryption would be you securing your own files/folder under a password. Multi-key is when you sign in to a website where it is secured at your end (one key) as well as the server end (another key). Simply put, it has the makings of a ubiquitous security system making it harder to penetrate using traditional methods.

  • Ian Weir

    Apple still hasn’t found a way of installing it on a fusion drive on iMac’s