What is a file

[Part 3] What is a file?	Lesson plans

A file is a single piece of work created by a program.
On your computer's hard drive, there are:
	Program files created by programmers.
	Document files (not just writings) created by you.

An email message is not a file.
A file can be attached to an email message. An email message can be saved as a file.

A folder is not a file. On the computer, files are arranged in folders.

Some files that YOU can create on your computer
Program that creates the file	File examples and extensions	Typical size (KB)	Program the opens the file
MS Word (word processor)	Letter to Mary.doc	50	MS Word
MS Excel (spreadsheet)	Investments.xls	50	MS Excel
MS FrontPage (web pages)	What is a file.htm	50	MS Internet Explorer (browser)
Adobe Acrobat	IRS 1040.pdf	50	Acrobat Reader
Quicken (bookkeeping)	My accounts.QDF	500	Quicken
Digital camera, photo scanner	Photo.jpg	50-1500 (note)	Browsers, image viewers
Digital camera, movie	Birthdayparty.mpeg	200-6000	Media players
Music: CD ripping software	WhiteChristmas.mp3	6000	MP3 software players

How big is a file?
One floppy disc holds 1500 KB (kilobytes) = 1.5 MB (megabytes)
So one floppy can hold about 30 Word files.
But even four floppies might not hold one MP3 file!
See: storage media

diskette.gif

This page is a file named What is a file.htm that was created with MS FrontPage. The picture of the floppy disc is a "gif" file named diskette.gif. Click here to see what my computer screen looked like when I told FrontPage to insert the picture into this page. There are more gif files below. When the page was finished, I asked FrontPage to upload this page and its graphics files to our web host's server in Canada.
Now, when you ask MS Internet Explorer to display this page, it asks the server to serve the files to you (to download them onto your computer).

.
File sharing
	Files can be copied or moved around on your hard drive. But what if you want to give a copy of a file to someone else?

					Copy the file from PC-1's hard drive to a floppy disc. Bring or send the disc to someone else who will copy the file onto PC-2's hard drive.

	When PCs are networked to each other, files can be copied directly from one to the other.

	When PCs are connected to the Internet: PC-1 can copy (upload) a file to a server computer; then PC-2 can copy (download) the file from the server.
	Via the Internet, you can share files with anyone in the world!