Seven years ago, on 27 March 2017, Apple introduced one of the most fundamental changes in its operating systems since Mac OS X 10.0 Cheetah was released 16 years earlier. On that day, those who updated iOS to version 10.3 had their iPhone’s storage silently converted to the first release of Apple File System, APFS. Six months later, with the release of macOS 10.13 High Sierra on 25 September, Mac users followed suit.
At the time, these were huge gambles. The potential for disaster was significant, and at the last minute, Apple decided that those Macs with Fusion Drives had to stay with its old Mac OS Extended File System (HFS+) for another year before they too could start up from APFS. In some markets, notably South Korea, even Apple’s own software failed to cope with changes in the way that file names were handled by the new file system.
Although APFS has certainly had its moments over the last seven years, Apple’s gambles have paid off, and proved key to the success of Apple silicon Macs. Had there been no APFS, many of the fundamental technologies like Secure Boot and the Signed System Volume (SSV) would have been far tougher if not impossible to implement. Macs and Apple’s devices had been in dire need of a modern file system for years; while there was a time when it looked as if that could have been ZFS, in 2014 Apple decided to write its own file system from scratch, with Dominic Giampaolo and Mike Mackovitch as lead engineers.