What happens if you turn a computer off while it says not to turn it off?
In: Technology
Computers have several ways to “remember” things (store information). One is what computer uses when it’s turned on, were it does calculations and runs different applications. You probably heard that computers can do billions of operations per second, and for that they need to be able to access a lot of data, very fast, without unnecessary delays. All this is done in memory called Random Access Memory (RAM). Unfortunately, making memory fast means it’s very expensive to manufacture, which limits how much you can store there. And the way such memory is made fast for truly random access creates a very severe disadvantage – it “forgets” everything if power is turned off. That is where another type of memory comes to help – long term memory based on various technologies such as hard drives, SSDs and other flash memories, magnetic tapes, or even cloud storage. All that other memory is too slow for a processor to use directly.
Various programs that you run on your computer have different needs for this long term storage. Some, like games, only read most of the time. Except when you change settings or make a progress that needs to be saved. Other programs, like a video editor, would need to both read and write quite a lot. But remember, in computer’s terms accessing that memory is very slow, therefore computers try to avoid doing that as much as possible. One way to speed things up is when applications don’t write all they have to disk immediately, but wait for the user to “save changes”. Another technique is to use “disk cache” – where part of RAM is used to store data that needs to be written to the long term storage so that applications writing that data “think” it’s all written down and can get on with the main tasks at hand. The Operating System (Windows in your case) would then write that data from the cache to the permanent location, slowly, as a background operation. There is a logic behind when the OS decides to start writing that data, it depends on how full the cache is and tries to prioritize user’s experience to make work with the computer feel smooth and fast.
Sometimes, when a user decides to shut down the computer, the disk cache is not yet empty. That means that there is still data in RAM that is not yet put into permanent storage and would be lost if power is turned off. Whatever that data is depends on usage of the computer prior to shut down. You might end up with game save to be gone. Or it might be that nothing will be lost because it was some telemetry of the OS or log files of the apps that would not get written down, stuff that you don’t need anyway. But something will be lost, therefore better wait and let the OS shut down gracefully.
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