Computing Resources

R

SAS and Linux

First, here are some quick links, followed by some explanation.

The primary software for this course will be SAS. The software will not be located on your computer. It runs on a server, and you control it over the Internet. SAS is available to students free of charge on UTM's tuzo machine. This computer runs the linux operating system, and using linux is either

  1. Easy and familiar,
  2. Familiar but not easy,
  3. An opportunity to learn something useful, because Windows and Linux/Unix are the two main operating systems left on the planet (Mac OS X is just a graphical interface to Berkeley Standard Distribution unix),
  4. A price you pay for not having to buy the software,
or some combination of the above. You will use your UTORID login and password. Tuzo's IP address is: tuzo.utm.utoronto.ca

Here is a textbook chapter containing an introduction to SAS, and also to the unix operating system. The tuzo machine actually uses linux, but for the most part, the differences between linux and unix are just legal, moral and political. That is, they do not matter to most people.

You are encouraged to print the shorter handouts above, and refer to them until you get familiar with the processs of running SAS on tuzo. They contain all you really need to know of unix and also emacs, a very powerful free open source text editor that runs on tuzo. You are strongly encouraged to use emacs or some other unix text editor of your choice to write your SAS programs. Try to resist the temptation to do it on your PC and transfer the files. This is just good advice, so feel free to ignore me.

The longer versions of the handouts contain material that is not in the textbook chapter. You don't really need them, but you may like some of what's in there.

You will be able to use SAS from the computer labs on campus. You can also run it over the Internet from home or some other remote location. This is convenient, but several issues are involved.

There is a PC version of SAS, and you can get a copy and run it on your own computer if you really insist. The SAS Institute makes a lot of money selling its software to big corporations as well as universities, research institutes and so on; SAS is expensive! But U of T has paid them a lot of money for a site license, and you can get your own copy of SAS for just $110 a year. It locks up on July 1st. Note that SAS will not run on any "Home" version of Windows. You will have to upgrade to Windows Vista Business (available at the Licensed Software Office) or Windows Vista Ultimate. All this is likely to be more trouble than it is worth.

Using SAS

SSH (Secure Shell)

With an Internet connection, SSH applications give you a text-only connection to tuzo and other unix machines from your home computer. From tuzo's prompt, you can run programs such as SAS, R and emacs. SSH is  secure because what you type and see on your screen is encrypted at one end and decrypted at the other end. This prevents hackers from stealing your password as you log on, and also prevents nosy people from spying on the highly sensitive and confidential work you do in your courses.

Different SSH programs are recommended, depending on the operating system that you are using. To use these programs, you must be connected to the Internet, say with a broadband connection or via PPP over your phone line.

In any of these SSH programs, the first time you connect to a host, you will be told that the program can't verify that this host is really what it appears to be. Do you want to trust it? SSH is just being sanely paraniod. Say yes.

Printing files at home

This is always an issue. When you use SAS on a remote linux machine like tuzo or river, you have an account on the remote machine. When you run SAS, your log and list files (which you need to print and bring to the quizzes) are written on the remote machine's hard drive, in a directory controlled by you. If you are in a computer lab and you use the lpr command to print, everything is fine; it comes out on the lab's printer if you feed the machine some money. But when you are at home, you need to print on the computer there, and the printer you have at home is almost certainly not part of any university network. So you need to transfer the files to the hard drive of your home computer in order to print them.

If you are a Microsoft Windows victim, I mean user, one good way to do this is with a free program called WinSCP. I have not tried it myself, but I have heard good things. You can Download it from here.

If you are a linux or Mac user, just use sftp from the command line.

A more primitive way to get files to your home computer for printing is to email them to yourself. Try
       mail yourname@yourisp.com < fname
where yourname@yourisp.com is your email address and fname is the name of the file, like hw3.lst. There seems to be some trouble with this method when you use Web-based email programs like gmail or hotmail.

Copy-paste in PuTTY

Suppose you want to transfer fairly small amounts of text between the unix machine and your PC. In a normal Windows application like Explorer or Word, the edit menu has Copy and Paste items -- or you can use control-C and control-V. But PuTTY has no menus, and Control-C and control-V don't do what you might expect, especially if emacs is running. But you can still copy-paste; here's how: