Computer Lessons for Kids and Small Adults
Lesson 3 - Files, the Overview
The idea about files and directories is very important and actually if you can get a firm grasp of files, you are then on the downward side of the learning curve. If you understand files, you'll be able to figure out most things, and a lot of the black magic involved in using a computer, and a lot of the fear, will simply disappear. These lessons will spend a lot of time talking about files.
First I'll give a quick overview of files and then we will make comparisons between files and things you already know.
What do I mean by Files?Files are clumps of computer data stored somewhere in your computer. Each file has a name, a location, and a length, and usually a date of when it was last changed. Files are stored in several places.
Any files that are in the memory of the computer are lost when the power is turned off. That is not as scary as it sounds because what you usually have in memory is only a temporary copy of the file, the original stays on the hard drive or floppy or wherever it is usually kept. Pretty well the only time the original is in memory is when you are creating a new file and haven't saved it yet.
- on floppy disks
- on hard drives
- on CD's
- in the computers memory (RAM)
- in the computers special read only memory (ROM)
- on tapes of a tape back-up device.
What Do Files Do?Files hold and store information that can be read by the computer. That's all they do.
What Kinds of Files Are There?All files are basically the same, they all have a name, a location, a date and they all hold information. However, they can hold lots of different kinds of information, so we often think of this as different kinds of files. Actually it is just the type of information that is different.
Here are some of the main types of files you will encounter. They often have certain letters at the end of their names so you can tell from their names what sort of information is inside. Some files you can easily look at the information inside and many others you can't, at least not without a program that is specifically designed to look inside that type of file.
name What's inside What does it do? anything.com A list of instructions for the computer, a program It runs, you execute it by typing the name or double clicking on it. anything.exe A list of instructions for the computer, a program It runs, you execute it by typing the name or double clicking on it. Bigger and more common that .com's anything.bat A list of instructions for the computer, a program It runs, you execute it by typing the name or double clicking on it. Usually small and quite easy for you to make readme.txt Text, that is readable information. It is there for you to read. anything.gif Graphical information When viewed using a graphics program, you can see the picture. lesson3.htm Textual information When viewed using a browser program, you can see the text in a pretty format. When viewed using an ordinary editor, you can see the text and the codes that make it pretty.
What do you do with files?What you do with a file depends on the type of information that it holds, but some things can be done with all files.
- Run them - if they hold a program.
- Look inside them, if they hold graphics information or text.
- Listen to them, if they hold audio information.
- Copy them - this is one of the main things you will do. When you run a program, what actually happens is that the file, with the program inside, is copied from the long term storage device into the RAM, where its' list of instructions are executed (run). You also copy files from a floppy to your hard drive or from one place on your hard drive to another.
- Move them - This is like copying except that the original is NOT left behind. It is often safer to copy a file from one place to another and then delete the original, once you are sure the copy went well.
- Delete them. When you no longer need a particular file, you can zap it.
- Create them. When you compose a document in a word processor or any other program such as an editor or spreadsheet, you are creating a new file. Usually saving goes hand in hand with creating.
That is enough for an overview. You probably now are pretty sure what I mean when I talk of a file. Next comes two comparisons of files to things that are familiar and then a sort of history of files. A lot of this information is repeated again and again, so if you don't understand what I mean, don't worry about it, I'll be saying it again later! As I said, getting a firm grasp of handling files is essential to becoming a computer guru. It's almost all you need.
Lesson 4 - Files, Are Like Records