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A computer computes, but I/O does work... or at least it keeps things fed so that it can do the work, and shows you what it did.

A computer has a few parts. The CPU is the "Central Processor Unit". This is the part of the computer that actually crunches numbers; moves data around or takes instructions and processes them. When people talk about "the computer" they are often talking about the CPU. But the CPU just executes instructions; that wouldn't have any value at all if it couldn't talk to you or other devices.

I/O stands for input/output. These are all sorts of ports and connectors that usually talk through cables to other devices, or that gathers or conveys information to you. This is actually the most important part of a computer, and the most overlooked.

  • Your keyboard and mouse are input devices. They allow you to tell the computer things like enter a character or move the cursor (arrow).
  • The screen (display) is an output device; it allow the computer to tell you things, like show you what you just did.
  • Printers are output devices.
  • Scanners and digital cameras (or cell phones) are input devices to bring in photographs or images.

It is this input and output that allows the computer to be valuable to you.

Speed of change

Most of the confusion in computers and I/O is because the staggering speed of change and evolution. We're learning and improving things so fast, that computers, and all the adaptors and connectors have to adapt to keep up. And while we are in transition, we often have both old style connectors and newer (better) ones, so that people can use their old devices and newer ones together: Saving them from having to replace everything at once. Eventually the old ones are replaced and will die out; but during that transition, there's a lot more to know. And since we keep adding new ones, it stays confusing.

Many people are intimidated by the acronyms and jargon; but most of it is really quite simple.

  • You need to connect two devices, usually with a cable that's designed for that purpose.
  • That cable has connectors at the ends that plug into ports; you just need to match them up properly.
  • Internally, the devices need to not only be able to physically connect to each other but they also need to talk the same language (protocol); think of a telephone, just because you can call anywhere in the world, doesn't mean that you'll be able to understand what they are saying, so you have to agree on the language.

The wide array of connections is what confuses people; but it is actually very common sense:

  • The video cable connects the computer to a monitor
  • There are often ports for sound input (a microphone) and sound output (speakers).
  • There's often USB for a mouse and keyboard, printers, scanners and other devices (if they aren't wireless).

Don't let the jargon scare you. All these I/O ports have different names and numbers and speeds; but this isn't much more complex than things you already know, like your house; which has the same concepts. Water, Electricity and Gas come in, and sewage goes out. Phone and cable come in and out, and some things like electricity have multiple versions (110 or 220). If you can understand this for your house, then you can easily learn the same stuff about your computer. I/O isn't that hard.


📚 References

Written 2002.03.11