One-To-One Correspondence between Phone Model and OS Version?

[AC Question]

I keep seeing smartphone ads and reviews saying "this model runs (say) Android M v6.0". This gives me the impression that there is a bijection between smartphone models and operating system versions.
How does that even make sense though? A smartphone is a computer. A computer is just a peculiarly shaped hunk of metal, so I can run nearly any version of any OS I like on it. Right?
Weirder still is the implication that model X "comes with" Android M 6.0, so when N 7.0 comes out I can't just upgrade and use the new version on the same hardware like on a regular computer? I can't even wrap my head around this. Is there some shady lock-in magic going on here?

 

[hallux]

Android has to be set up specifically for a device. Unlike Windows, you don't go out and download the drivers needed to make a new OS run on the device you're dealing with. The device manufacturer has to integrate the drivers needed for the device into the OS build and then release it (with other customizations if they so choose) to be installed on the device (sometimes with carrier intervention). This is also dependent upon the component makers supporting the new OS for the components in the phone. For an example - look at Google not releasing N for the Nexus 5, one primary factor in that was that Qualcomm decided not to release support for the SoC that was used in that phone so Google couldn't release the OS on it.

In short, you can't just go grab an Android N release and install it on whatever device you have.

Now, if you want to go "off trail" you could find a developer that has found a way to make it work, there are other sites (or the sub forum here dedicated to your device) where there is rampant discussion about the available options and how to get them.

 

[chanchan05]

Not exactly, but it's true that you can't just update like a regular computer, and it's because of the streamlining done on the OS to be able to operate in such low power CPUs. You have to understand that a 2Ghz octacore CPU on a cellphone is less powerful than a modern 1Ghz Dual Core PC processor. Heck a single core of a modern PC processor can outperform octacore cellphone processors.

One of the effects of this streamlining is that unlike Windows installers, which contain generic drivers for a lot of common hardware (hence installation sizes reaching up to 30GB, Android doesn't have generic drivers. And unlike Windows where you put the base OS and install drivers on it, mobile OS like Android and iOS have the driver software baked into the firmware. Basically you can't slap it onto any phone and have it work. You have to open it up and install the hardware drivers into the OS base. This is why updates are slower for non-Nexus/Pixel phones. Google tests the firmware on these devices, but the firmware they used on these devices won't work on other phones. The firmware for a Pixel XL won't even work for a normal pixel because of differences in hardware.

So the manufacturers like Samsung has to develop firmwares for their phones, with the drivers for the hardware they used.

Another issue is that hardware manufacturers for cellphones do not normally release the firmware publicly, so it's not really possible to built your own update as well.

Your phone will only get an update on the mercy of the manufacturer. And sending updates cost money, which is why there is often a premium in high end devices that get the updates. Because you're paying for the updates you'll receive for the next two years as well.