WHAT IS MIME?

MIME is for multi-pure float Internet
Mail Extensions and has two major tasks:  owing to MIME a post office 
program can indicate to the other one, which type by data are 
contained in the message;  additionally it supplies standardized 
procedures, in order to code data in such a way that they can be 
transmitted by E-Mail by Internet.


Coding procedure of MIME

in the Internet is used for the post office transfer the SMTP
log.  Smtp is limited to the US ASCII character set.  This is a 
problem for people, which American English and therefore accents do 
not speak or American letters do not need, or for people, which 
special characters want °to be used as.  The dispatch of 
binary files (file creations) is just as problematic.  MIME removes 
this restriction.  It offers two coding procedures, " quoted printable
" and " base64 ".  These procedures use US ASCII codes for any data, 
inclusive special characters or even binary data.  Quoted printable is
mostly used for texts.  As long as no special characters are used, 
Quoted printable looks like normal text.  The character concerned 
replaced by = and two further characters, which represent the extended
ASCII-Code of the special character in hexadecimal way of writing.  
Therefore °into quoted printable as = one writes THERE.  
Further no line may be longer than 76 characters.  If your message 
contains longer lines, these are divide-divided and the first line 
with one = finally, so that the post office program on the other page 
knows that the two lines strictly speaking only one is.  The 
Base64-Kodierung is another method to be able to transport binary data
undisturbed over smtp.  Base64-kodierte data are no more than text 
recognizable contrary to quoted printable, therefore this procedure is
used preferentially for binary data.  Base64 is comparable with the 
older UUencode, is however safer in application.


Content of 
type

another important characteristic from MIME is that it 
permits the post office programs to exchange information about the 
type of the data in the message.  In addition the heading line " 
content type " is used.  The most important content of type are:  text
readable text image of pictures and diagrams audio of tones video 
animations message messages or sections of it multi-part different 
types of data in only one message of the Subtype gives additional 
information about the type of the data:  text/plain pure text 
text/HTML text in the HTML format image/GIF a picture in the GIF 
format etc..  On the basis the content of type (in YAM ' type of the 
system ' mentioned) the Mailprogramm can select the correct display 
program for a file creation.