What software and hardware components are involved? Is there a general sequence?
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In broad terms, all electronic devices with computing elements have a bit of permanent memory which stores the program. On startup, after the actual chips and circuitry have powered up, the CPU or processor will automatically (this is the automated sequence in the processor when it starts up) go to a fixed memory “location” and look for a program to run.
The designer of the device will put their startup code there. At a very basic level, it is the same for any device with a processor.
The process is called [booting](https://en.wikipedia.org/wiki/Booting), and the wiki article has all the details about what components are involved.
Basically, when power is applied, there’s a chip that’s responsible for resetting the memory to all 0s and resetting the processor and other chips to a “default” state, then they perform internal checks to see if “everything is ok”, then the processor looks at the first sector on the hard disk to see if it finds instructions for loading up an operating system, Windows, Linux, whatever.
Long ago, most electronics were made with chips that could perform command steps, but they weren’t full computers — microcontrollers. Think of the coffee maker with a timer and screen. It’s just a very basic, cheap chip that can do time, trigger on/off, make a beep, etc. It’s kind of hard to say these “boot” the same way a computer does because there’s no real operating system to boot. They just execute a few commands when power is applied (like turning on the screen and displaying the time), wait for further inputs, and update the time.
It was cheaper to make chips like this than to waste resources putting full microprocessors in them, because those were much more expensive. But these days we have cheap ARM chips, the same thing in all of our phones, but far less powerful. They’re in everything, especially if something’s a “smart” product. These boot an operating system, even if a very small and simple one.
I had an earlier LCD TV. It didn’t have a full computer chip, it just had chips and other electronics that did specific things to turn signal into pixels and sound. It turned on and displayed the picture almost instantly. Today, any TV is going to have an ARM chip and an operating system, so it has to boot before you see anything. To make it look like it doesn’t boot, usually turning them off only blanks the screen and turns off the speakers, but the operating system is still running. That’s why you see in the manual that there’s power draw when it’s turned off.
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