On the Fediverse, someone recently ran a poll about whether people could live without their (smart)phone. I said that I could (assuming that magically there were no mandatory phone apps) but that it would be annoying, and one of the reasons was that my phone is the best alarm clock I've ever had ( as I got rubbed in my nose recently , although it's not flawless ). Afterwards, I started thinking about why my phone's alarm is so good or at least so much to my tastes.

The simple, obvious, and more or less wrong answer is because my phone is a computer. This is more or less wrong because these days almost everything is a computer, or at least has a general purpose computer inside it; your flashlight might be a computer ( and perhaps runs an open source flashlight OS ), for example. This has happened because using a tiny cheap computer is often the simplest, cheapest, and fastest way to implement features (rather than designing a bespoke electronic circuit). So a physical, dedicated alarm clock could certainly be a computer and some of them probably are.

My taste in alarm clocks is silence and darkness; noises or light make it hard for me to sleep. Many physical alarm clocks glow, tick, or both. My phone doesn't do this but that's somewhat an accident of history. Phones started out not being able to afford the power to keep their screens on and lit all the time, or regularly making noises, and so you could turn on an alarm, set the phone down, and it would naturally be dark and silent until the alarm went off. Some modern phones have enough power and clever enough displays that they can keep a display lit up (and they're very proud of it so they often do it by default), but you can disable this and get back to a silent dark object.

(I believe that electric alarm clocks have traditionally been plugged into the wall partly to use wall electricity for time keeping; the grid frequency is extremely stable. Since they are plugged in they could use that wall power for all sorts of glowing and noise-making.)

Another part of the phone being such a good alarm clock is that an alarm clock application gets to use a large, general purpose, highly capable interface in the form of the phone's touchscreen. This allows an alarm clock application to expose a lot of functionality in an easily discovered form. I have named alarms that repeat on various different days of the week at different times in the morning and I turn on and off as required, and all of this is straightforward to see, keep track of, and manage. A physical alarm clock computer could implement all of the same software features of repeating alarms, day of the week alarms with different times, and so on, but it would struggle to expose them to people in a way that people could easily interact with. If you only have a simple physical interface in the form of some buttons and a limited display (and maybe a dial or two), in practice you're limited to features that are simple to express through those physical interfaces. Very few people will love a physical clock so much that they'll spend five or ten minutes laboriously setting up a new alarm through what we could call a 'narrow' interface.

(The cheat for this is to delegate the complex interface to an app on your phone, which then talks to the device with more limited input and UI capabilities over, say, Bluetooth.)

The phone's general purpose touchscreen interface isn't necessarily ideal for any specific thing (I have a simple kitchen clock with only a few buttons that's much easier to use for what I want than the phone's timer stuff). But it does let you have a lot of quite capable interfaces for a whole assortment of different (virtual) devices, among other sorts of software.