I/O

So far, we learned that a computer can calculate things and make decisions, and store information, both in short term and long term fashion.

What is missing in this whole picture? Aha! We haven't talked about how the computer would communicate all the results it computed with users, which is the topic of I/O: input and output. In fact, without I/O, all those computations that a computer makes would be quite useless if we, as users, don't get to benefit from them.

Just like the CPU is a device used for computations, and RAM, cache, and disks are storage devices, computers also rely on I/O devices, most of which we use daily: a mouse, a keyboard, a screen/display, speakers, printers, scanners, etc. We learned back in Topic 1 that I/O devices split into two groups: input devices vs. output devices.

Making I/O devices work in a timely manner is critical to the efficiency of the computer: even when the CPU computes things fast, it would be a slow I/O device or slow communication between the computer and the I/O device that would 'ruin' the experience of using a computer. Just imagine playing a game, with each mouse click processed only 1 second later: ouch.