Understanding Computers
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  Unzipping the Secrets of Downloads
Internet files are transferred sequentially from a remote server to the local host. That's nerd-speak for "the files are sent one by one from some far away computer to your computer". When you visit a web page, your computer asks for and receives the files that make up that page. The simplest web pages consist of a single file. If a page has graphics, those files are stored separately and sent along in turn. That's why background images, buttons, and pictures usually appear on a page after the text is already visible.
Downloading anything other than a web page requires the transfer of multiple files. Given that lots of folks have trouble remembering to buy everything on the grocery list, the question arises: how can anyone keep track of all those files? The easiest way is to zip them all up into one big file.
A zip file, or more correctly an archive file, is a collection of files that have been smushed together. That way, there is only one file to keep track of. An archive file is like a grocery basket. You put everything that you need into the basket and carry it away. One neat thing that can be done with archive files that can't be done with groceries is called compression, which is like freeze-drying, only better.
Like grocery baskets, archive files are useless if you can't unpack them. The tools you need for the job are called zip utilities. You can download zip utilities from the internet. The most popular zip utility is WinZip , an excellent utility, but our favourite is Ultimate Zip . It's more versatile as well as being freeware.
But how can you unzip the zip utility once you have it? Zip utilities are a special kind of archive file called self-extracting files. They unzip themselves. Many other applications can do this, including, unfortunately, viruses. You should only download from trusted sources.
Big applications take a long time to download, especially on a dial-up connection. Most people can't afford to tie up the telephone for long periods of time, and if the download is interrupted, you usually have to start over at the beginning. This problem gave rise to a family of utilities which let you break off and resume downloads. Gozilla and GetRight are two of the best known. I like a lesser-known utility called Star Downloader because it doesn't roar at me or report my nocturnal wanderings to strangers.
Many clients have asked me about the difference between downloading and uploading. Simply put, downloading is receiving and uploading is sending. There is a bit of a paradox in that you can't do one unless another computer somewhere is doing the other, but it's best not to think of these things too deeply if you want to understand computers.
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