Let's take a minute to talk about one of those most interesting of after-dinner topics: file systems.
Apple has been using the HFS+ file system for around two decades now, and aside from a few behind-the-scenes features like journaling, it's remained largely unchanged. In that same period we've gone from floppy disks on our Macs to having multi-terabyte SSDs. In other words, HFS+ woefully outdated. Enter APFS.
APFS (Apple File System) is an entirely new file system that will ultimately be used across all Apple products, from the iMac to the Apple Watch.
Here's a few of the new features we know about:
Encryption - multiple encryption methods offer more options to the uber-paranoid.
Snapshots - Let's say you upgrade to the new macOS and find out that a critical application doesn't work properly. Snapshots may give the ability to roll back to the way your system was immediately prior to the upgrade, and do it much faster than having to erase and restore from a backup.
Clones - Now if you make minor changes to a file, the OS only needs to keep track of the changes while keeping the underlying file data. This means that you could have hundreds of copies of even very large files (like databases) and they'll take up very little space, as each clone of the file is only the data that's changed.*
Speed - The new file system is optimized for solid-state drives (SSD), so newer Macs should see a dramatic performance boost. Some claim that Apple's primary goal with APFS is to avoid the Spinning Beach Ball of Doom—one can only hope.
It's likely this feature list will change when APFS first rolls out—which, as it turns out, may be very soon.
Apple recently issued the first beta of iOS 10.3 to developers, and apparently it converts over to the new APFS. This is smart on Apple's part: far more iOS users are likely to have their devices backed up (via iCloud or iTunes), so if anything goes wrong they can hopefully recover their data. Since users don't have direct access to the file system they way they do on macOS, there's less room for things to go wrong, and more opportunity for Apple to get it working well before the macOS release.
In the meantime, back up early, back up often, and let's all look forward to the deflating of those infernal beach balls.
* One can imagine that this may be more confusing to the end user—why is it that when they delete a 2GB file they only recover 100KB of space? I've certainly seen this confuse a number of users when Apple did something similar in the conversion from iPhoto to Photos, and a seeming duplicate of the entire library appeared, when in reality Apple was using file links to only make it look like an entirely new library.
This also leads to the possibility that if something goes wrong with the underlying file data that every copy of the file itself could be ruined. Apple's engineers apparently believe that this is low-risk with their hardware because of the error correction (ECC) it contains, and they fact that they source high-quality components from their suppliers (per Adam Leventhal); but what about users who have "upgraded" their Macs with drives from third-party vendors? This is a topic for a future post.