Q. Dear Mr. Know-It-All,
In Netscape (I'm using the OS/2 2.02 version), under Options - General
Preferences - Helpers, there's a "File / MIME Type".
What is "MIME"?
MIME stands for Multipurpose Internet Mail Extensions, and is a method
"encoding" a file so that it can be sent by email.
You can't send some files by email without encoding because they
contain bytes which aren't able to get through the email system.
For example, an EXE file has every possible byte in it, but not all of
bytes will get through to the recipient because some of them look like
control codes and, often, some of the bits in the bytes that do get
will be changed.
The MIME software encodes the bytes into other bytes that can get
When received, MIME decodes the bytes, thus recreating the original
MIME also adds some lines to each email message "header" so that the
MIME software at the receiving end can properly decode the file.
If you open an email message in a text editor (or click on
View. . .Document Source in your Netscape 2.02), you'll see
lines at the beginning you never knew were there, and some of them
(Content-Type, Content-Transfer-Encoding, MIME-Version, Content-ID,
Content-Description) are MIME lines.
Historically, before MIME there were other encoding methods such as
MIME is much more robust, and is currently in wide use.
When you look at the Netscape screen you mentioned in your question,
a scrolling window containing "File type", "Action" and
There are a handful of MIME types (application, audio, image, message,
multipart, text and video) and lots of subtypes.
The "Extensions" are used to help classify the email file attachments
you receive, and the "Action" is what you want Netscape to do when it
receives such a file.
MIME is a standard that was finalized in 1993; see RFC 1521 (many sites
it, use your favorite search engine).
Also see the Internet mail standard RFC 822 created in 1982, and the
extension RFC 1563 from 1994.
Mr. Know-It-All lives in Southern California.
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