Apple's Next-Gen APFS File System: What It Brings to the Table

It is clear as day that among all tech companies Apple has the most loyal customer base, and we all actually know why: quality products, breathtaking designs, regular innovation, creative marketing and many other factors could not but attract passionate user support. But what may really make your jaw drop is the fact that Apple’s advanced operating systems and high-end hardware have been running on a file system that is older than a lot of Apple fans – HFS+ is just a slightly improved version of HFS which was introduced in 1985, more than three decades ago, back when floppy disks didn’t belong in a museum and were in fact widely used. Since then, the world of technologies has changed beyond recognition, we’ve gone from awkward bulky machines to sleek and lightweight portable gadgets, but the Apple company seemed extremely persistent in the attempt to teach their old dog new tricks. Thankfully, they gave up this idea in the long run, and in 2017 we got that so much needed breath of fresh air: the Apple File System (APFS). It has recently become available with macOS High Sierra, while iPhone and iPad users have been able to upgrade their devices since the beginning of the year by installing iOS 10.3. The new file system is also going to replace the existing HFS+ on other Apple’s devices like Apple Watch and Apple TV. But what is special about this long-awaited tech and how does it differ from its predecessor?

To begin with, most Apple devices use solid state drives (SSDs) and built-in flash, which store data in a completely different way than hard drives and floppies, that were considered state-of-the-art technologies when HFS was introduced. In contrast, APFS is specially designed for solid-state storage, thus is perfectly able to suit the needs of modern computers and mobile devices, which results in significantly improved performance and storage capacity. Yes, you heard it right: your old gadget may suddenly appear to be capable of storing more data.


The reason for it is that APFS allows using storage space and resources efficiently. For instance, thanks to the cloning feature, if you make a copy of a file, APFS knows that there is no need in storing two exact copies and just creates a location link that points back to the original data. As a result, clones are created instantly and take up no additional space. (It should be mentioned that this is just an underlying technology that helps to avoid duplication, for us, end users, clones continue to present as two separate files.) In addition, back-ups have also become smarter owing to the use of snapshots, which are read-only pointers to the original volume and its data at a particular point in time. They get updated only when changes are made to the original volume, making it possible to revert these changes if needed and take up no additional space. In keeping with the theme of storage space, space sharing is another awesome feature of APFS for those who employ partitions, which allows to break up a single physical disk into multiple volumes without predefining their size and make them shrink or grow dynamically depending on the data they contain by sharing available free space between them. If even this is not enough to impress you, unlike HFS+, APFS supports sparse files, in which empty bytes are represented by metadata so that storage space is not wasted on them (non-sparse file systems reserve file space in advance, even if the file itself is empty).

Secondly, APFS was developed with security in mind and offers much more sophisticated encryption options. In addition to full disk encryption, it allows encrypting individual files and even sensitive metadata using single-key as well multi-key encryption. The encryption mode can vary between AES-XTS and AES-CBC depending on the hardware.

Moreover, APFS replaces journaling with a new efficient copy-on-write metadata scheme, which keeps the old data around for the duration of the writing procedure to make sure that updates to the file system are crash protected.


Furthermore, APFS uses atomic safe-save, which performs any file operation (for example renaming or moving a file/directory) such that it is either verified as completed or it appears as though it never happened at all. This ensures that if for some reason, such as a power outage, the operation was interrupted, the original file remains intact.

Besides, fast directory sizing allows you to get a speedy response whenever you want the information concerning the size of files, folders, apps, etc.


Obviously, this brand-new file system offers a great many advantages, but, as we know, every coin has two sides, and, on the flip side, APFS has its own flaws as well.


First and foremost, APFS is not compatible with Fusion Drives and traditional spinning hard drives, making it impossible for the folks whose computers rely on them to enjoy its benefits.

Secondly, a lot of software, especially professional applications and some games have problems running on APFS. Few developers have managed to their programs with the support of APFS, hence, some of them may fail to launch at all and some won’t operate properly. Such software crashes may not only impede your work, but sometimes even result in the loss of valuable information. That is why you should always ensure that you have a proper backup of your data. However, if you failed to prevent the catastrophe anyway, don’t let your heart sink: luckily, software that supports data recovery from APFS is already available on the market (for example all editions of Recovery Explorer 6.13), so you can easily get your files back provided they are not overwritten.


Also, although all HFS+-formatted volumes can be read or written by a Mac formatted in APFS, this won’t work backwards: APFS controlled drives are compatible only with hardware using APFS, or Macs employing HFS+ but necessarily running macOS High Sierra.

Moreover, it is a quite new file system, therefore, some time needs to pass for it to be thoroughly tested and fine-tuned. Those who made a switch have already reported some serious bugs. For example, Disk Utility used to make the password for an encrypted APFS volume readable by anyone by showing it in plain text after the user clicked on “show password hint”. Of course, Apple quickly fixed that embarrassing issue with the next release, but who knows what unpleasant surprises may be still waiting for us.


Ironically, while being a vital component of any electronic device, the file system is probably not that feature the average user draws attention to in the first place. Still and all, it serves as the major means your operating system relies on for organizing data, and we all hope that the Apple File System won’t disappoint us and will do this job perfectly well for years to come.

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