Why does turning something off and on fix problems?

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I know it works most of the time with my pc and my smartphone, but yesterday at the dentist a drill didn’t work correctly, so they turned the entire chair and all the appliances connected to it off and on and the drill was working again. Why does this fix so many problems when nothing is changed in the hardware itself?

In: Technology

it resets the software. pc,phone and even the chair at the dentist all have some form of software on them. If it is a problem with the software a reboot resets it and hopefully it starts to work as expected again.

Electrical devices store data as an electrical charge. The electrical charge is stored in a component called a capicitor. Capicitors won’t hold a charge forever though. If you turn the device off, the capictors will start to lose their charge. This is why it’s typically advised to leave it off for 30 seconds to a minute, the give the capicitors time to drain. When you turn the device back on, everything is starting with a clean slate.

* Turning a device off and then back on is like swatting a fly.
* It doesn’t solve the root problem of the fly.
* It just makes the fly go away for some time.
* Maybe the fly comes back, maybe it doesn’t.
* The reason for this is because there is a flaw in the logic programmed into the device or software.
* Most of these flaws are caught with testing before the device/software is released.
* But some flaws only popup when there is a very specific set of conditions and testing for every combination of possibilities to reveal these conditions is hard and time-consuming.
* Re-starting the device clears anything in memory and start the program over from the beginning.
* So it doesn’t stop the flaw from existing, it just resets the conditions that can cause the flaw to be a problem.

Many complicated tools and devices rely on a computer to function. Computers are incredibly complex, and in complex systems you will inevitably encounter an error. This can be caused by a programmer making a mistake, by a flaw in the hardware, or numerous other things that could go wrong. Sometimes, one error can be overcome, but as a computer continues to run for long periods of time there are more chances for errors it can’t overcome, or for an accumulation of errors that combined cause a problem.

Computer systems are designed to overcome a lot, but there is always a limit to what they can handle, eventually they inevitably find themselves in a state they can’t go back from, and can’t go forward from. So the solution, is to reset the computer to a base state, a state that it always knows how to go forward form.

By turning it off, removing all power, we rest the state completely. Then when we power it on, it behaves as it always does upon being powered on, which should be perfectly functional.

For much more complex systems, like a PC or smartphone, which can store a lot of data even while off, sometimes errors can persist even after you turn off the power. This is why you often eventually need to do a “factory rest” which also deletes all the data – somewhere in that data is something wrong, or typically many somethings wrong, and all added together the system just isn’t working correctly, unless you delete it all and start from scratch.

A computer program is like driving a car through a busy city. As it runs it makes lots of decisions about what way to go based on what is happening around it, where it just came from and where it is headed next. Most of the time the car knows exactly where it is and exactly where it’s going. Sometimes the situation might cause the car to go down a different road, one where it’s never been before. Maybe a sign was pointing the wrong way? Maybe he missed his exit? Maybe there was a traffic jam or maybe he misread a street name? All of a sudden the program is lost aimlessly driving about different places but not really knowing where to go. It might drive around in circles, go somewhere it shouldn’t, go completely off the map or even crash! Turning our program off puts the car back at the start or in another known location and gives it the chance to try again. If the traffic is just right this time, and all the road signs are in the right places, and the car makes all the right decisions , it should get to where it needs to go.