LinkExchange Network

This area is for the pursuit of new PC technologies I am interested in. I will khronicle the directions my research takes me, dead ends as well as yellow brick roads, since you can learn much from mistakes.


Arthur C. Clarke's Third Law: "Any sufficiently advanced technology is indistinguishable from magic."


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Konsultant's Log
Cyberdate 04.05.1997
e-mail attachments
(sending files over Internet mail)


One of the most konfusing aspects of Internet e-mail to my friends and relatives (and to me too) is the pain and suffering involved in trying to send an e-mail attachment to someone. I know this has something to do with the text-based, 7-bit nature of the Internet e-mail protocol, but I don't know much. My mother (in her early seventies and still a growing grrrl), is leaping ahead of me in some areas of PC technology. She has purchased (and interfaced) a digital camera to her system (I have not even seen one yet), and has been e-mailing JPEG graphics files of the photos she has been snapping to relatives and friends. Some of the recipients cannot view the files. This situation has stirred me to investigate this Internet e-mail protocol that is second nature to any self-respecting UNIX propeller-head.


Before we dive into the dirty details of Internet e-mail file transfer technology, let's make sure we have a problem. In my mother's case above, she was sending JPEG files from America OnLine. I told Mom that this format came from the "Jet Propulsion Laboratory", but I must 'fess up here and korrect my error. It really stands for "Joint Photographic Experts Group".

From the AOL "Members helping Members" area I found the following info about the AOL mailer program:

America Online automatically converts your files to MIME format when you send an attached file to an Internet address. Just attach a file to your e-mail message and click the Send button.
When you receive a MIME-encoded attached file from an Internet address, America Online will automatically decode the file for you if you are using AOL for Windows or AOL for Macintosh. AOL for DOS users will have to use the program, AOMAC2PC, to decode the file. AOMAC2PC can be downloaded from the AOL file libraries by using keyword FILESEARCH and the search word "aomac2pc."

As you can see, Mom didn't have to do anything beyond attaching the graphic file to her e-mail message. AOL automatically "MIMEd" it. Those of us who received it at their AOL e-mail address likewise didn't have to do anything beyond pressing the "download" button (in the case of this graphics file format, AOL automatically opens a window on the screen and begins to display the picture as the download progresses).

Those of us who aren't on AOL may have more work to do. It all depends on how sophisticated your e-mail program is. First, determine if you program understands MIME. It may have automatically decoded the file from the MIME format. Using our JPEG graphic file example, try to open the file in a program that understands JPEG files. Various paint programs understand JPEG, but the most likely choice is your Internet browser. If you can see LAROKE background "wallpaper" on the LAROKE Site Map in your browser, it can display JPEG (or "jpg" extension) files. If your browser can display JPEG files, you can try to open the downloaded file in the browser for viewing. In both Internet Explorer and Netscape Navigator, you choose the "open file" line item on the "File" menu. Just make sure you choose "JPEG" as the file type in the Open File dialog window (*.* all files if JPEG is not a choice), or you will not see any "jpg" files to open. The Internet Explorer screen shot below shows the cursor highlighting "JPEG" in the "File Type" drop-down list of the "Open" dialog.

Internet Explorer Screen Shot

If you cannot open the file in the browser (or other program that can read JPEG files), chances are your mail program did not decode it, and it is still in MIME format. Now, you'll probably have to learn more about that program. Maybe it can still decode the "MIMEd" file, but it just does not do it automatically. Scan the program's menus, search the help files, and (only as a last resort) crack open the manual, if you have one. Also, don't overlook the possibility that you may have received a corrupted file. If you suspect a bad file, ask the sender to e-mail you another copy.

If all of the above fails, you've got to roll up your sleeves, and learn the ugly truth about the "innards" of Internet e-mail "MIME" and "UUENCODE". This is a desperate situation. You may opt for another way out. One alternative is to upgrade to a super-duper e-mail program that handles decoding automatically. You could also give up. In the case of Mom's pictures, I've seen them, and everyone has their clothes on except the family cat. (jus' kiddin' Mom!). OK, you're determined to see the JPEG graphic. Plunge ahead!


My initial research took me to the PC Webopaedia e-mail Definition and Links page. This page a clear, concise explanation of electronic mail and provides a good jumping-off point for our further explorations. Like all the Webopaedia pages, it provides plenty of links for more detailed studies.


The particular elements of Internet e-mail we are interested in are "MIME" (Multipurpose Internet Mail Extensions) and "UUENCODE" (Unix-to-Unix encode). Once again we turn to the PC Webopaedia for good basic information on these two different methods of preparing binary files for internet mail transmission. Take a quick look first at the MIME Definition and Links page, and then the UUENCODE Definition and Links page. You'll see that MIME is the newer of the two specifications. Although most current mail programs support UUENCODE with either automatic or manual "encoding" and "decoding", some do not support the newer MIME format (the format Mom's pictures were transmitted in). Your task in this situation is to get a third-party shareware or public domain utility to translate the file attachment into something you can use. Someone may send you files in different formats so you may have to learn about UUENCODE as well as MIME.


With the basic definitions under your belt, we can get into the ugly details. The best location I found for actually learning how to decode these files is BINARIES FOR BEGINNERS: This site is oriented around Windows 3.x but works for Windows 95 too, and has links to sites for DOS and other environments. It also has links to sites where you can download decoding utility programs.


If you really want to become an expert on this "stuff", put on your white lab coat, grab your slide-rule and pocket protectors and head for the Internet Mail Consortium FAQs page. The info on MIME alone at this site is so extensive, it is divided into 9 parts!


I will repeat an oft-repeated warning here: DON'T download files from strangers! There are Cyber-Unabombers out there who would derive great pleasure from infecting your machine with a computer virus just for the "halibut".


This has been a simplified exploration that barely scratches the surface. There are too many different combinations of PC computers and mailing software packages out there for me to cover this subject on a step-by-step, how-do-I-do-this basis. I hope I have offered enough general information and links to assist you in your own investigations. Don't be discouraged. Despite what the marketing people say, PC computing is not easy, yet. It is as close to rocket science as most of us will ever get. Where else do people cheer and applaud when something works the way is is supposed to? That's right, NASA!


Unfortunately, BINARIES FOR BEGINNERS seems to no longer exist at http://www.agbamu.demon
If anyone out there knows where it went drop an email on me at and I'll re-establish the link in this article.

Help with Internet E-mail and Mailing Lists This site is mainly for new users at the City of Grande Prairie, Alberta, Canada but also intended to be helpful for those new to the Internet and e-mail.


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LAROKE Microcomputer Consultants
155 East Boca Raton Road
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Issued Saturday, April 5, 1997

Updated Saturday, September 20, 1997

copyright © 1997 LAROKE Microcomputer Consultants all rights reserved