NIU Department of Mathematical SciencesCampus Computing Overview
NIU Department of Mathematical Sciences
More and more professors, committees, faculty groups use the Internet. If you are a student expected to turn in assignments by e-mail, or a secretary who needs to send a Word Perfect file to the Dean, or a professor who wants to set up a Web page for his class, and if you don't know exactly where to begin, this document might be for you.
We will not give detailed answers to all questions you might have. We will only provide an overview of how our campus network and computer systems work, how it interfaces with the rest of the world, and where you can find more specific information.
This causes problems: it is impossible to give any instructions on "how to use the Internet", because the user could be sitting in front of a PC running DOS, or a DEC Alpha with a Unix operating system, etc. The possibilities are endless, and even though the underlying mechanism of communication between the computers are identical, what the user sees is very different in all those cases.
In recent years the software vendors have been trying to make their programs (including Internet applications) work on all platforms, and appear similar on them all. Thus we have Netscape in a Windows, Mac and Unix versions, and knowing how it works on a Sun, I can quite easily imagine what a Windows user sees. But there are still thousands of programs that only run on only one type of a computer.
Another feature of the Internet is that its philosophy is centered around the client-server model. In nearly all Internet activities there is the side which initiates a connection and sends out a request (the client), and another computer which tries to satisfy that request by responding with data, or passing e-mail further on, or some such (the server).
This is very important for several reasons. First, it's impossible to get help from any expert without telling him what is the exact setup you use. Second, you will be more confident knowing what's going on behind the scenes. Third, you will be able to decide what to do when you want to exchange data with other people, no matter what system they use.
One frequently heard complaint is "I'm on GroupWise, so I can't send
mail to you", or "he has a Mac so he can't use our files". This is false.
Whoever is saying this has much to learn about the way our computers
interact. We'll try to straighten out this maze a tad by describing the
various combinations.
PC
This is by far the most popular hardware. Trouble is that a PC running
DOS or Windows 3.1 isn't a particularly good Internet player. There is a
lot of software which makes a PC into a useable client, though. Windows
95 and later include all the components you need for Internet connectivity.
Web browsers have swallowed many other traditional Internet protocols: FTP, gopher, finger, and so on. Three years ago an article which didn't mention those was incomplete. Now, thank heavens, you don't really need to know about these early attempts at making data interchange universal and easy to use.
Hardly anyone uses the program that started it all, NCSA Mosaic; a pity, since its programmers deserve the credit for making the Internet accessible to "the rest of us".
Note that Netscape, Mosaic and the Explorer have a built-in e-mail module, so you could be using that instead of the e-mail software mentioned above.
When you are ready, you pull down a menu, or hit an F-key, and bingo - the PC connects to the POP server and ships outgoing mail to it. It usually checks for incoming mail at that time, and downloads it to the PC's disk. Naturally, the computer has to be plugged into the network at this stage. From this point on the server takes over, and deals with details of mail delivery. The beauty of this system is that your PC doesn't have to be very smart, as long as the POP server knows what to do. Moreover, that machine never sleeps and accepts incoming mail for you, whether your PC is on line or not.
Notice that in order to use this scheme you have to have a valid account on the "big brother" computer. On our campus those include rice.farm.niu.edu, oats.farm.niu.edu and wheat.farm.niu.edu for students. Some faculty use corn.cso.niu.edu and various other workstations set up by individual departments.
On a more modest scale, you can be sitting in your office in Zulauf and using telnet to connect to corn.cso, which is in Swen Parson. Many people do this instead of relying on POP. You probably start up something like NCSA Telnet, or a WinTelnet under Windows, or similar. You then type elm or pine and see a list of letters... OK, this is on a PC allright, but you should forget the PC, because you really are using a Unix workstation, only connecting to it from the PC. Everything that's happening is happening on the remote computer: your files are there, your account is there, the manuals describing various commands are there. See the section on Unix below.
I have bad news for you: this software has nothing at all to do with the Internet! Your e-mail is encoded and transferred in such a way that no Internet computer will ever understand it, the addresses of users are totally incompatible with standard Internet addresses, and so on.
Not all is lost, though. When vendors of such software realized that people don't like packages incompatible with anything, and often prefer products which work with everything (i.e. the Internet), they started marketing special add-ons whose job was to translate the proprietary format to the standard Internet conventions, and back. If you use Novell software, the email addressed to internet:user@place.domain is shipped to such a "gateway", and then passed to the large Internet.
Commercial software had one historical advantage. It was created with a typical office in mind, and one of its primary functions was to let users exchange complex documents such as WordPerfect, Lotus 1-2-3, or even JPEG or GIF graphics files. Thus from the very beginning office e-mail had an advantage over Internet mail in that it could transmit binary data, while standard Internet e-mail can only handle plain alphanumeric characters. To remedy this, a new e-mail standard was created: Multipurpose Internet Mail Extensions, or MIME for short.
All Mac Internet software requires the basic Apple network driver, MacTCP or OpenTransport TCP/IP. Chances are that the network administrator has installed it for you.
Even though there is a Mac version of Pegasus Mail, Eudora is by far more popular, as it was developed and matured in its Mac incarnation. A few other POP clients are available, but as with PCs they are much less common.
Netscape and Mosaic run on all modern Macs, and - as all bloated packages these days - require as much memory as you can afford. The Microsoft Internet Explorer for the Mac is reportedly somewhat leaner than Netscape.
NCSA Telnet was also developed on the Mac first, and even though it is no longer supported, it's the standard way of making it into a "dumb terminal". If you wish to try newer but less tested software you can try Cornell's Comet, or Nifty Telnet.
The whole section about Novell has little relevance to Macs. Most people using them stay well away from the PC-centric contraptions; Macs on Novell networks primarily use file sharing services and little else.
If your office Mac is never turned off, you can quite easily make it into
a Web server, or a mailing list server, etc. without having to struggle with
intricacies of Unix or NT.
Unix
Hmmm, this is a can of worms... Unix grew up along
with the Internet, and its Internet services are still unsurpassed. Nearly
every flavor of this operating system has the Internet protocol built right
in as its integral part. Unix is also extremely modular. A piece
of software running under it may look completely different than another
piece, but they happily use the operating system in the same way (totally
hidden from the user). This gives most newcomers a feeling of vertigo.
If you start your sessions by typing a "username" in response to a login: prompt, and then entering a secret password, and the screen doesn't say anything about Novell, you are almost certainly using a Unix computer.
Unix is a big mess, but its foundations are very solid. Many people prefer to use it even for the client functions, where it doesn't necessarily shine.
One has to realize that all Unix software is like that: it ranges from excellent free utilities, through decent shareware packages, to lousy and expensive commercial programs; none of those has much to do with Unix itself, other than they all use the basic and well documented services of the operating system.
Note that if you are accessing a Unix computer using a method which is not graphics-oriented, e.g. with Telnet, you cannot use any of the fancy programs like Netscape. The program running on the Unix computer would have to be able to display complicated graphics on your PC screen, and this is impossible without yet another layer of software (an "X-windows server") installed on the PC. Chances are you don't have that, and you have to rely on "character-oriented" Web browsers such as lynx. Of course you can then forget about images, animations etc., but you can still get some useful information from most Web pages this way.
As opposed to most PC packages, Unix mail programs usually assume that they are dealing with mail received and stored on the local machine. Hence the "client-server" process is limited to a single computer. Your letters and mailboxes are right there, on the machine's hard disk; you can manipulate them using various text processing utilities, they are usually backed up daily, etc. Moreover, most Unix machines have administrators who watch over things. Some people feel more secure using this system rather than any PC-based scheme.
If you are struggling with Unix now, and you wish you had never heard the word "elm" or "pine" again in your life, it may be that some tweaking and customization can help. For example, elm by default uses a traditional Unix editor called vi, which many users despise. But that is easily changed: by hitting o (for Options) at the main elm screen, you can instruct the program to change that to pico, ce or some other editor with which you might be more comfortable.
You may be using a computer plugged into the campus network backbone (a PC, a Mac, or a Unix workstation). This is the case in many faculty offices, and in most student computer labs. It's the best situation: provided the right software is installed, you have a full range of Internet services at your fingertips.
You may be stuck in an office which is not wired, or at home with a modem; you can then use a "terminal emulation" program (Procomm, Qvt, ZTerm, Kermit, Microsoft Works or some such) to dial to another modem. Most of the time you would then access the main dial-in server (we'll call it the tserver) run by the University. When you connect to it, you can make another "hop" by typing, say, telnet corn.cso.niu.edu at the TSERVER> prompt.
This works just like Telnet described above, except it's much slower: the phone connection between your modem and the tserver is the weak link, being dozens of times slower than a direct network route. As with Telnet, you will not be able to take advantage of Netscape graphics, etc.
Finally, there is PPP, which stands for "point-to-point protocol". If you have a fast modem (14,400 bits per second or better), you can configure special software on your PC at home. The PPP component makes the phone line appear to the PC as if it were a direct network link to the campus backbone. After a connection is established, you can use all the Internet utilities (Netscape, POP client programs, Telnet, etc.) Obviously this is still much slower than a direct backbone hookup, but at least the functionality is not limited as it is with a straightforward modem link.
There are two caveats: first, you must have a valid account on
one of the student Unix computers (oats, rice, wheat), or on
corn.cso.niu.edu, or finally a special "SuperWylbur" account
on the campus mainframe, mvs.cso.niu.edu. Second, configuring
the PPP software on your computer is not quite trivial. You
should carefully read the manuals for your TCP/IP and PPP
software, as well as more detailed documents
available elsewhere.
A word on MIME and encoding documents
As we mentioned, regular Internet e-mail can transmit only the
basic text information; in technical terms, it ignores the last
bit in 8-bit chunks of data that are being sent. Many
files we deal with - executable programs, graphics files,
most wordprocessing documents - do use that 8-th bit, and in
order to send them by e-mail we must have a way of
encoding the 8-bit information into ordinary characters.
This is just like Morse code, which uses just two symbols to
encode the entire alphabet.
The encoded document (which to a human looks like garbage, but it consists only of normal ASCII symbols now) is then attached to a letter and sent to the recipient. At the other end the process has to be reversed, so the original file is recreated.
Many modern e-mail programs (especially POP clients and office-oriented systems like GroupWise) do this automatically. The user just tells the mail program to "attach a document", and the whole encoding process happens behind the scenes. If the recipient uses a similar system, the decoding is also kept hidden from the user - the original file automagically shows up on the disk.
To inform the receiving computer about the type of the document, encoding method, etc. the sending computer includes this data in special mail headers. This is really the only thing that MIME does: it makes it easier for the receiver to decide how to handle the encoded parts of the letter.
Many older programs either don't have these capabilities, or require some human intervention to take advantage of them. For example, with the elm mailer you have to manually insert a line such as
[include budget.doc application/octet-stream base64]in the body of the letter.
Similarly, not all mail programs automatically decode such content. You may have to save the letter to a file, remove the mail headers and ordinary text of the message, recognize the encoding type (binhex? base64? uuencode?) and manually run a suitable decoder program. Ask your local guru for help in this.
The second is a unique campus-wide "alias" assigned to everyone by Computer Services. It looks like ebehr@niu.edu or jlatourette@niu.edu. The relationship between these is quite straightforward. Initially the alias does not point to anything. The user or the database maintainers have to set it up to point to a real e-mail address. From that point on, mail sent to ebehr@niu.edu will be routed to the real address behr@math.niu.edu.
To query this database, or to change the information stored in it, you have to access it with a Unix program ph, or through the Web, or with one of the "Ph client" programs available for PCs. This is described in more detail in separate documents.
Central Computing Services run a Help Desk which can be reached by phone at x3-1900. Many straightforward problems can be solved by calling it, but be prepared to explain your situation clearly. The staff has to deal with a variety of users and systems, and a plea such as "something is wrong with my computer" is not likely to put them in the right mood.
In case of problems with bounced mail, try verifying the recipient's address using the Ph database, or the Unix finger utility. As a last resort, send a short query to the special user "postmaster" at the other machine, e.g. postmaster@ucsd.edu, asking about the recipient's whereabouts. Remember that such a letter will be received by a (usually overworked) human, who might take quite a while to get around to it.
Somewhat more detailed document about the Internet: http://www.math.niu.edu/help/net/internet.html
Using the Ph database: http://www.math.niu.edu/help/net/ph.html
More on NIU e-mail addresses: http://www.math.niu.edu/help/net/niu-addr.html
Exchanging files by e-mail (encoding and decoding under Unix): http://www.math.niu.edu/help/net/mail-files.html
Introduction to elm: http://www.math.niu.edu/help/unix/elm.html
Short summary of elm commands: http://www.math.niu.edu/help/unix/elmcmds.html
Pine tutorial: http://www.cac.washington.edu:1180/pine/tutorial/index.html
Setting up PPP access (with specifics for the Macintosh): http://www.math.niu.edu/help/macs/ppp.html
Setting up PPP software under Windows 95: http://www.math.niu.edu/help/pcs/ppp.html
Creating Web pages: http://www.math.niu.edu/help/net/html.html
Academic Computing Services Web page: http://www.niu.edu/acs/
© Eric Behr 1996
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