Public Service Announcement: You Should Not Force Quit Apps on iOS or Android

John Gruber at Daring Fireball has the definitive post on why you shouldn't force quit apps on your iOS device (double-pressing the home button and swiping them away):

The single biggest misconception about iOS is that it’s good digital hygiene to force quit apps that you aren’t using. The idea is that apps in the background are locking up unnecessary RAM and consuming unnecessary CPU cycles, thus hurting performance and wasting battery life.

That’s not how iOS works. …[U]nfreezing a frozen app takes up way less CPU (and energy) than relaunching an app that had been force quit. Not only does force quitting your apps not help, it actually hurts. Your battery life will be worse and it will take much longer to switch apps if you force quit apps in the background.

The only reason you should force quit an app is if it is misbehaving, such as not responding. All of this reasoning and advice applies equally to Android, which operates in a similar way.

If you force quit apps to keep the app-switcher clean, know that you are hurting your phone's battery life and your experience. At the time of writing there is no alternative way to keep the app switcher clean.

APFS in Detail

In June of 2016, Apple announced the file system that would be replacing HFS+: Apple File System (APFS). Adam Leventhal wrote a detailed series of posts about what’s coming in the new file system:

Apple announced a new file system that will make its way into all of its OS variants (macOS, tvOS, iOS, watchOS) in the coming years. Media coverage to this point has been mostly breathless elongations of Apple’s developer documentation. With a dearth of detail I decided to attend the presentation and Q&A with the APFS team at WWDC. Dominic Giampaolo and Eric Tamura, two members of the APFS team, gave an overview to a packed room; along with other members of the team, they patiently answered questions later in the day. With those data points and some first hand usage I wanted to provide an overview and analysis both as a user of Apple-ecosystem products and as a long-time operating system and file system developer.

Beyond losing the mass of technical debt accumulated in HFS+, the feature that appeals to me most is encryption becoming a first class citizen. This will be seamless to the end user, but provide for greater security going forward.

Multi-key encryption is particularly relevant for portables where all data might be encrypted, but unlocking your phone provides access to an additional key and therefore additional data.


APFS (apparently) supports constant time cryptographic file system erase, called “effaceable” in the diskutil output. This presumably builds a secret key that cannot be extracted from APFS and encrypts the file system with it. A secure erase then need only delete the key rather than needing to scramble and re-scramble the full disk to ensure total eradication.

Quite interestingly, APFS will be adding I/O QoS:

APFS also focuses on latency; Apple’s number one goal is to avoid the beachball of doom. APFS addresses this with I/O QoS (quality of service) to prioritize accesses that are immediately visible to the user over background activity that doesn’t have the same time-constraints. This is inarguably a benefit to users and a sophisticated file system capability.

I’m curious to see how much impact this will have in the real world, but conceptually it makes a lot of sense.

I also learned from Adam’s posts that if you want to experiment with prerelease APFS now, there is a bit of humor in avoiding interactive confirmation of the risks associated:

[diskutil] prompts you for interactive confirmation of the destructive power of APFS unless this is added to the command-line: -IHaveBeenWarnedThatAPFSIsPreReleaseAndThatIMayLoseData; I’m not making this up

Consistently Connect iPhone to Mac Over Bluetooth

Since I started using bluetooth more heavily with my iPhone and Macbook, I have had major connection issues. Once the devices were paired, trying to connect them would often result in errors. Finally, after far too much frustration, I believe I know how to connect my iPhone and Macbook consistently.

Continue reading Consistently Connect iPhone to Mac Over Bluetooth

More Back Button Confusion

In December I wrote about iOS Back Button Confusion, outlining how having multiple back buttons on the same screen in iOS creates user mistakes or slowdowns as they determine which button they should use. I recently noticed the same issue with my RSS reader of choice, NetNewsWire (which is an outstanding app for reading RSS feeds on the desktop).

Continue reading More Back Button Confusion