The Four Questions
	The questions you need answered before you can successfully send attachments via email.

Before you can send an attachment to somebody, you have to know four things about them. The easiest way to tell is usually to have a few canned test messages you can send to see what they can handle. Obviously, the major effort lies with you to be able to send the same thing in the many different ways that may be required! Regardless of how bad things seem, there are standalone mail encoding/decoding programs freely available on the Internet that will allow you to send or receive anything to or from anybody. Some examples of free encoders or decoders are WinCode, MPack, and NetSend. One of my favorite decoders is the shareware program WinZip.

Here are the four questions:

(1) WHAT CAN THEY DECODE?  This is usually UU (Unix), MIME (Windows), or BINHEX (Macintosh). If you use Microsoft Outlook, you have to worry if they can decode the MS-TNEF format Outlook uses to send attachments. Some mail programs can't decode any attachment formats! All attachments have to be encoded somehow before they can be sent over the Internet. The encoding converts a "binary" attached file to a "plain-text" file, and plain text is the only thing that is guaranteed to pass through all networks along the way. Obviously, once you encode it, they have to decode it. Otherwise they see the random-looking encoded text. When things work correctly, you never know about the encoding. You attach something, and they see your attachment. Neither of you knows or cares about how it gets encoded.

(2) HOW BIG A MESSAGE CAN THEY HANDLE? Common answers range from 32k and 64k (Default Windows text and integer limitations) to 10 megs (mail account disk space limitations). I've crashed many a mail program and corrupted many a file by trying to send or receive something bigger than allowed. Amazingly, the maximum allowed size is almost never mentioned in any documentation.

(3) CAN THEY HANDLE MULTIPLE ATTACHMENTS?  Some email programs will only get the first attachment if you send several in the same message. Some others have a limit as to how many attachments they will accept. If this becomes a problem, you'll either have to send each attachment separately or archive them all together in one file (Then you have to worry about if they can un-ZIP, ARJ, LHA, ARC, PAK, or TAR whatever it is you sent them...).

(4) CAN THEY COMBINE SPLIT ATTACHMENTS?  Sometimes you'll be stuck sending something that is bigger than either you can send or the other person can receive. The only thing that can be done is to split the file into smaller parts. This is so common that many mail programs handle the splitting, naming (1 of 3, 2 of 3, etc.) and concatenating automatically. But most mail programs can't do it at all!
 
 

If the person you are sending to has BASIC (Even the QBASIC that has been included free with MSDOS since version 5.0), you can embed the text from UUDECODE.BAS in your message. To make sure UUDECODE.BAS isn't itself encoded, you'll have to include it in the BODY of your message. You'll have to instruct the recipient to save your message with just the lines with line numbers to a separate file named UUDECODE.BAS. Do it by cutting and pasting or whatever, but be sure to save it as "plain text". Then start whatever BASIC program is available and open UUDECODE.BAS wherever it was stored. When UUDECODE is run, it will ask for the input file (the saved message with the uu-encoded file in it) and the output file (the name of the attachment). If you're smart, the first thing you'll send is a better decoding program so the recipient won't have to use UUDECODE.BAS ever again. Even smarter is to send a small decoding program just in case the person has a size problem.

Another approach is to send whatever you want as a self-extracting program in text format. How is this done? Well, less than half of the PC instructions use bytes that can be printed out as text, but an enterprising programmer named Jim Tucker used those few commands to build build a full encoder/decoder/extractor program. It's called netsend, and as long as the recipient can figure out how to clip text, they can get whatever you send them. Well, since COM files can't be any bigger than 64k, that limits you to sending small files. But it's still a big help! Netsend can also produce a "mini uu decoder" (called muud.com) which, because it is plain text, can be sent to people in the body of a message! Click here to see an actual output from netsend where I've encoded one of my graphics called "logo1.gif".

Of course, there are always other "gotchas" waiting for you. For example, if the person you are sending to has Outlook, they might have security set up to not even show certain types of attachments. If you send to an AOL account, AOL might convert multiple attachments into a single zipped attachment. Or maybe the other guy's mail client will foolishly trigger on some word in your message. Like sending a line with nothing but a period on it might end your message. Or sending the word "begin" followed by two spaces could hide your message.