You may think that computers are doing little if anything while you are sleeping. While you are dreaming, you might think, if you think of it at all, computers are sitting mostly idle, running the odd screensaver program, waiting for you to return, your faithful servant.
Of course, some computers, like web servers, could be serving different people. Computers could be handling the requests from people around the world who are awake and working and reading and surfing the web. Some computers handle requests 24 hours a day, rarely having any time to themselves, to reboot, to load new software.They process requests until they are shutdown intentionally or fail dramatically.
But just like your body is resting and your brain is dreaming/sorting things out in the wee small hours of the morning, so too do some computers take the night time to get themselves together. While you are sleeping, they are running backups, processing files they don’t get to process in the daytime, defragmenting their disks, cleaning out their caches and buffers. Many computers have utility roles, doing a myriad of tasks you can only imagine. Plus for every set of computers handling your requests, there are entirely different sets of machines that check and make sure that the machines you use are working properly.
If the earth can be said to be automatic, so too can it be said of the many thousands of computers that are running while you are sleeping, running to keep the world running in the 21st century.
And I have thought of all this while I test run batch programs on a set of test computers during the graveyard shift, in order to insure that the real computers that we run can handle the volume of requests that the real (not test) computers will eventually have to handle. For in my case, what computers are doing while you are sleeping are helping me do my job successfully which will help you in ways you don’t even know (not only, but partially, because you are sleeping).