More about computing in STA429/1007

A central part of this course is use of the SAS statistical software package. SAS is available to students free of charge on U of T's cquest computers. Students in STA429 should go to the cquest web site immediately to set up their accounts. Students in STA1007 will need to fill out a short paper form (available from Jerry); your accounts will be set up manually.

Chapter 2 of the online textbook contains an introduction to SAS, and also to the unix operating system used by cquest. Well, actually cquest 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 can use SAS in the cquest labs, located at

• Sid Smith 2105
• Earth Sciences 1046 (the round building)
• Ramsey Wright 211/213
• Physical Geography Room 3

You can also use SAS over the Internet from home or some other remote location. Go to login.cquest.utoronto.ca. This is convenient, but several issues are involved.

• For security reasons, you need to connect using software that probably did not come with your computer. The protocol is SSH, which stands for "Secure SHell." When you use SSH, information travels over the Internet in encrypted form, so hackers have trouble intercepting your password and other information. Many versions of SSH are available for free download; see the cquest Web site for links. If you are running linux or Mac OS X at home, you already have SSH. Use the ssh command in terminal.
• At the cquest labs, SAS is easy to find in the menus. Running SAS this way starts up the SAS Display Manager. It's really quite nice once you get used to it, but
  • It's much easier to learn how to use the Display Manager if you already know how to use SAS from the command line, the way it will be illustrated in lecture and the online text.
  • The display manager does not work over SSH, so if you are running SAS from a remote location you will have to do so from the command line anyway.
  So, if you are at a cquest lab, open a terminal window or two (right click on the background area and use the resulting menu), and run SAS from the command line at first. Once you are comfortable with that, it will be easy to move up to the Display Manager (which basically just shows you the various input and output files in separate windows and lets you execute SAS by making a menu choice) when you happen to be in a cquest lab, if you want.
• If you are happy running SAS at the command line from home, two things may disturb you when you are in a cquest lab. You can't use pico (command not found), and you are prompted for a password when you execute SAS. Both of these problems can be avoided by typing  ssh login.cquest  at the unix prompt. This uses the Secure SHell protocol to log you onto the application server. That's the machine that has SAS and pico. And you're coming in over the Internet just as you do from home, so the environment is the same.
• When you run SAS from the command line, either from home or in the lab, there is one unpleasant technical issue that arises. Both the SAS program and the data file must be in your top-level (home) directory.

  This is unfortunate, because it is natural to make separate subdirectories for different courses, projects or even assignments. In every other unix environment I have ever seen, when you type SAS filename and press Enter, SAS looks in your current directory for the program file filename.sas, and the name of the data file that you specify in the SAS program implicitly begins with a path to your current directory. I assume that on cquest, SAS is not installed properly, or else there was some other horrible technical problem that was even worse, and the work-around broke this aspect of SAS. Oh well. I suppose we should be thankful we can run SAS from the command line at all, and not complain too much.

  When you run SAS from the menus in a cquest lab, your files do not have to be in the top-level directory. SAS can find them. So this a reason to move to running SAS from the menus when you happen to be in a lab. But watch out for different versions of a file with the same name, at different directory levels.

  Another advantage of the menu interface is the availability of online help. The manuals may be better, but you probably do not have any SAS manuals. If you are departing from the examples in any substantial way, SAS' online help can be a lifesaver.

If you want to connect from home but you do not already have an Internet Service Provider, U of T provides good inexpensive dialup access through UTORDIAL.

There is a PC version of SAS, and you can get a copy and run it on your own computer if you wish. 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 that locks up on July 1st for $110 a year.