Computer Quiz Show #6

[hard candy]

Well, I hope our viewers had a good weekend! And welcome back to the Computer Quiz Show. Shall we get started?
Electronic mail is used by the majority of computer owners today. Email started back in 1965 when users of a mainframe would send each other messaages.
1. The two main protocols for recieving email are POP and IMAP. What words do the letters in these two acronyms represent?
2. Do the letters in "SPAM" represent any words?
3. SMTP (simple mail transfer protocol) is the protocol used to send email from one mail server to another.
ASCII (American Standard Code for Information Interchange) was used for text email messages but another format was developed for sending non-text email and has become the major format used today. What is this format is used to encode email for transfer by SMTP?
3. Does SMTP authenticate (check that the information is true) the sender of an email?

[GliderMike]

1) Post office protocol and Internet Messaging application protocol
2) no
3)MIME
4) Optional

[happybunny]

2) Spiced Ham

[mrrangerman43]

2) gound up and reassembled something that you eat?

S = servise
P = provisioning
A = account
M = management

I wouldn't stake my life on that, but it was all I could find.

[Parcival]

No, the letters in SPAM are no abbreviation for anything, yet spam existed outside the digital world:

SPAM was one of the few meats excluded from the British food rationing that began in World War II and continued for a number of years after the war, and the British grew heartily tired of it, hence the sketch.

The phenomenon, some years later, of marketers drowning out discourse by flooding Usenet newsgroups and individuals' email with junk mail advertising messages was named spamming recounting the repetitive and unwanted presence of SPAM in the sketch.

Wikipedia on Monty Python's Spam (http://en.wikipedia.org/wiki/Spam_(Monty_Python))

[bwkaz]

3. SMTP (simple mail transfer protocol) is the protocol used to send email from one mail server to another.
ASCII (American Standard Code for Information Interchange) was used for text email messages but another format was developed for sending non-text email and has become the major format used today. What is this format is used to encode email for transfer by SMTP? Umm... depends.

I assume you're talking about both character encodings (the Content-Type header, the "charset" sub-element) and content transfer encodings (the Content-Transfer-Encoding) here. SMTP is limited to 7-bit ASCII (or at least, to stay maximally compatible you have to use 7-bit ASCII, i.e. no bytes can have their high bit set), so depending on the charset of the message you're sending, the mailer has to encode it in one of three ways.

First, there's the Content-Transfer-Encoding: value of 8bit. This means "please treat this message as an 8-bit ASCII stream, not a 7-bit stream". Not all mail servers handle this, although the ones that don't are getting more and more rare. 8bit messages don't have any size increase, and they're (usually) human-readable.

Then, there's a Content-Transfer-Encoding of "quoted-printable". This takes bytes not in the range 0-127, plus bytes that aren't in the "printable" set, and replaces them with an escape, which starts with the = character. IIRC equal signs are escaped, too; I think they're encoded as =3D. quoted-printable messages have a size increase proportional to the number of characters are not "printable". quoted-printable messages are still mostly human-readable.

Last, there's a Content-Transfer-Encoding of "base64". This expands everything by a factor of about 20-25%, so it makes things much, much bigger. (IIRC, 8 7-bit ASCII bytes are used to encode 6 bytes of input.) But it's still smaller than quoted-printable for mostly-binary files, like images. If you base64 encode a human-readable string, the output is too different to be able to read.

Orthogonal to the choice of transfer encoding, for human-readable stuff anyway, is the character set. ASCII is a character set containing only 128 characters. Many Windows programs use the character set "windows-1251", which is almost equivalent to "iso8859-1", which is the 128 bytes of ASCII plus 128 bytes used by various Western European languages.

Then there's utf-8. utf-8 is a multi-byte encoding, used to represent the entire Unicode character set (all 2-to-the-24th of them, or however many there are now). It's also backwards-compatible with 7-bit ASCII; if a given byte is below 128, then it's a single-byte character, whose "value" is the same as in 7-bit ASCII. But if the byte's value is 128 or higher, then it signifies that there's a next character coming (or something like this; Googling for utf-8 should reveal the exact details).

There's also UCS-2, which encodes each Unicode character as one or two 16-bit values (so 2 or 4 bytes). There's also UCS-4, which encodes each Unicode value as 4 bytes. UCS-4 is the only character encoding that can hold the entire Unicode-standard range, and uses a constant byte length for each character. (But it's extremely wasteful for 7-bit ASCII or iso8859-1 characters.)

And orthogonal to that is the choice of text-only or HTML; expressed as a MIME content type value.

Basically, Content-Transfer-Encoding determines how the mail client should turn the stream that it gets from the server into an internal sequence of bytes. The charset determines how these bytes map to "code points" (and eventually to characters on the screen). The MIME Content-Type value determines how this set of code points is rendered on the screen (whether an HTML interpreter, or image viewer, or whatever, is required).

As far as MIME goes, that's more or less orthogonal to all this too (though it interacts with the Content-Type). MIME is just a standard to encode a "file boundary" inside a single mail message; each "file" is either an alternative form of the message (e.g. both a text/plain and a text/html version, to accomodate mail readers that can and can't do HTML), or an attachment (e.g. an image). The MIME Content-Type determines how to handle each type of "file"; image/* types are images, text/* types are text, application/* types are possibly binary (application/octet-stream -- EXE files), but definitely associated with some form of strict processing (application/xhtml+xml).

3. Does SMTP authenticate (check that the information is true) the sender of an email? Not by default, but there are several RFC extensions to allow it.

[hard candy]

1. IMAP-Internet Message Access Protocol
POP- Post Office Protocol
2. SPAM- the letters do not represent any words when used in conjunction with email There is some debate about the source of the term, but the generally accepted version is that it comes from the Monty Python song, "Spam spam spam spam, spam spam spam spam, lovely spam, wonderful spam…" Like the song, spam is an endless repetition of worthless text. Another school of thought maintains that it comes from the computer group lab at the University of Southern California who gave it the name because it has many of the same characteristics as the lunchmeat Spam:

* Nobody wants it or ever asks for it.
* No one ever eats it; it is the first item to be pushed to the side when eating the entree.
* Sometimes it is actually tasty, like 1% of junk mail that is really useful to some people.
3. MIME-Short for Multipurpose Internet Mail Extensions, a specification for formatting non-ASCII messages so that they can be sent over the Internet. Many e-mail clients now support MIME, which enables them to send and receive graphics, audio, and video files via the Internet mail system. In addition, MIME supports messages in character sets other than ASCII.
4. SMTP does not authenticate the sender when installed without any extensions, plugins, or addons. This is what makes it useful for spammers, they can use false addresses.
Bob, what do the winners recieve today?
If the winners setup an email account with Hotmail, Gmail, etc, they will soon recieve enough spam to satisfy even Monty Python! Free of charge! And the more they reply to the spam, the more spam they will recieve! And if they use Gmail, they will soon have over 2 gigabytes of spam for their personal use and to share with friends and family.

[Parcival]

If the winners setup an email account with Hotmail, Gmail, etc, they will soon recieve enough spam to satisfy even Monty Python! Free of charge! And the more they reply to the spam, the more spam they will recieve! And if they use Gmail, they will soon have over 2 gigabytes of spam for their personal use and to share with friends and family.

Who wants such a crappy prize? You're spamming our forums! ;) I'd rather have another one of those free distros. :D