Your Internet Consultant - The FAQs of Life Online

6.14. I grabbed a program with FTP, but it won't run on my system. What's wrong?

If you've downloaded a program (or graphics file, sound file, or whatever) to your computer from the Internet, but it won't run (or display or play or do whatever it is supposed to do), take heed: Any of a hundred little things could have gone wrong to mung your copy of the file.

Note: Thousands of files are copied each day from public archives such as anonymous FTP sites. Most of these sites are moderated; that is, before a file is made available to the public, someone checks it to make sure it works. It's not impossible that a the file you downloaded from a public archive is corrupt, but it is unlikely.

A common mistake is failing to transfer binary files (such as programs, archives, graphics, and such) in binary mode. If you don't explicitly specify binary transfer modem when FTPing a file and downloading it from your host to your PC, most programs assume that you want text mode. Copying a binary file in text mode is a sure way to make it unusable. Don't worry, everyone occasionally forgets to use the right transfer mode.

Inexperienced users often fail to translate or "uncompress" files before trying to use them. Most archive sites on the Net use some form of file compression and/or translation on their files. File compression allows files to use less hard disk space. Naturally, compressed files need to be uncompressed before use. Translated files are those that have been converted from 8-bit (binary) format to 7-bit format. Again, you'll have to turn these files back into binary before you can use them.

You need to know how those files have been tweaked before you can make them usable again. You will find some files that have been tweaked in multiple ways; for instance, compressed and translated.

Chapter 4, "How Can I Communicate with People Around the World?" contains questions and answers concerning how to tell if your file has been translated with BinHex, uuencode, or btoa, three popular translation formats.

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