Prevent File Transfer Pandemonium

Original Article is at: http://www.download.com/Mac/EdFeature/CurrentFeature/0,15,0-562-1,00.html

by Jason Wehling

Introduction

Did you know that although you've chosen the Mac for your home or business, you're probably relying on multiple computers to get your work done? It's true. For example, even as you read this Toolkit, you're using three computers without even knowing it: your home computer, your Internet Service Provider's computer, and the computer hosting CNET's Web server. Passing through this massive network of computers, very few of which are Macs, are millions and billions of files. Unfortunately, transferring, converting, compressing, and encoding your Mac files for this trip across the Net is not only a necessity, but it can also be a daunting task—without the proper know-how and software, that is.

As a Mac user, you usually don't have to be familiar with file extensions—those letters following a period at the end of the filename, such as ".html"—since the Macintosh system doesn't rely on file extensions like other systems do. Unfortunately, the Internet isn't a Mac desktop, and if you spend much time there, you've probably run across an entire zoo of file extensions: .html, .gif, .jpeg, .sea, .hqx, .sit, .bin, and many others.

Luckily, you don't need a Master's degree in network computing to figure it out. This toolkit provides a quick, no-nonsense explanation of file transferring, deciphering cryptic file extensions, and a list of all the downloadable software you'll need to become an instant pro.

Compressing files

Compressing, as the name implies, refers to a process of making your files smaller. The cool thing about compressed files is that they contain all the information that the uncompressed file holds, but they take up less space on your hard drive and require less time to download. This can be a real life saver. While that 160 megabyte hard drive seemed vast just five years ago, it doesn't do much for you today—that is, unless you save space by compressing all those archives of your sent email! And compression makes it much faster to transfer your files across the Internet as well.

There are a number of shareware and commercial programs that will perform compression on your files. The three most popular of these are DropStuff (shareware, $30), StuffIt Lite (shareware, $30), and CompactPro (shareware, $25). Unless you have special needs, these three programs work more or less the same. DropStuff is a nice companion for your desktop because it supports drag and drop capabilities. StuffIt Lite and CompactPro both create self-extracting (.sea) archives—compressed files that do not require an expander program to be decompressed. Files compressed with either DropStuff or StuffIt Lite will be given the file extension ".sit," while CompactPro files are tagged with ".cpt" as their extension.

Encoding files

Before you scan in that picture of your newborn, compress it, and send it to your mother via email, you'll want to learn a little about encoding files. You might think of encoding as overkill: that newborn's picture isn't top secret, so why do I need to encode it? Unfortunately, if you just send the file as is, your mother is likely to receive a corrupted file that refuses to open.

One problem stems from the many computers that your picture must travel across to reach your mother's Mac—most are not likely to be Macs. But the real culprit lies in the Mac's ability to determine file types without the need for file extensions. If you double-click on a Microsoft Word document, for example, your Mac will automatically open the correct program. The Mac achieves this by reading a special component of a Mac file called a resource fork. Most other computer systems don't know what a Mac resource fork is and usually drop it off. This means that your newborn's picture will likely end up at your mom's computer with only a portion of the information intact. This is obviously a problem.

So to keep your forks all in one piece, it is often necessary to encode your files, which assures that nothing will be dropped in the journey. There are two main ways to do this: UUencoding and BinHex encoding. Both of these techniques involve transforming Mac-specific information into plain text that any computer can understand. After the file is transferred, the text is converted back into the Mac-specific information.

UUencoding gets its name from "unix-to-unix encoding" and is most often used when posting files to newsgroups (with the .uu or .uue extension). UULite (shareware, $29) is the easiest UUencoder (and decoder) to use on the Mac.

BinHexing is a special encoding scheme used only on Macs, and is the preferred encoding process for Macintosh files. BinHexed files display the .hqx extension and are found on nearly all sites housing Mac programs (like DOWNLOAD.COM). Both HQXer (shareware, $10) and BinHex (shareware, $10) provide a means of generating your own .hqx files.

Decompressing and decoding

Even if you have no need for compressing or encoding files, you've probably been on the receiving end more than once. What do you do when you encounter files named, for example, file.sea.hqx? All Internet Mac veterans answer in unison: Make sure you have a copy of StuffIt Expander! This software gem really does it all, and what's more, it's free. There are very few compression and encoding schemes not recognizable from Expander. It can identify and reconstitute all the usual suspects: .sit, .cpt, .sea, .hqx, and .bin files.

Even more impressive, Expander can deal with compression and encoding performed on systems other than the Macintosh, such as .tar, .Z, .gzip, .zip, .arc, and .uu files. But if for some reason you need to compress files that will eventually make their way to a computer other than a Mac, you may want the ability to create files like these. In this case you may want to download MacGzip (.gzip), ZipIt (.zip), or UULite (.uu).

Transfer on Floppy Disks

Of course, there will be times when you want to transfer files via floppy disks instead. For example, say you want to pass that picture of your newborn to your mom via disk. Most Mac users are familiar with this drill: just drag and drop the file onto the disk icon. But what happens when you encounter the dreaded error message, "There is not enough room on the disk"? Instead of throwing up your hands, take another look at CompactPro. It has the ability to build a compressed file with multiple sections. In other words, if the picture file takes the space of three disks, you can put a third on each disk. You just send Mom the three disks.

While this may sound strange, there are instances where you need to send your disks across the Internet. Say you picked up a cool new shareware demo on a floppy disk, and you want your buddy in Greenland to give the game a try. There are a number of programs for copying disks, such as Apple's Disk Copy. These programs will also save what is known as a disk image file. This "image" can be used by the same program and placed on another disk, making an exact copy. You just send the image file to Greenland, and your friend can put it back on a disk of his own. This technique is also useful for placing backups of your installer disks on external drives like Zip disks.

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Page Installed: 29 April 98