Computer Science 432 Operating Systems Williams College Fall 2006

1. Send me mail at terescoj@cs.williams.edu with a brief (a couple sentences) indication of your level of experience with the Unix operating system and its variants, plus a list of other operating systems you have used. Also include list programming languages you have used and your proficiency in each, and anything else you'd like me to know about your background coming in. (0 points)
2. (0 points) Log into and familiarize yourself with your CSLab Unix account.
   • Forward your CSLab electronic mail to an address you read regularly. I may sometimes use your @cs.williams.edu address and will expect that you will read what it sent there on a regular basis.
   • Try FreeBSD systems in the lab from this list. These are multiuser systems. You can log in remotely using your favorite ssh client, or log into the consoles in TCL 312.
   • Identify the function of and experiment with these Unix Commands:

      
     ls    cd      cp      mv     rm     mkdir   pwd
     man   chmod   cat     more   grep   head    tail
     ln    find    rmdir   wc     diff   tar
     

   • Emacs is a powerful text editor. You wil want to become familiar with it. Identify the function of and experiment with these Emacs Commands:

      
     C-x C-s   C-x C-c   C-x C-f   C-x C-w   C-g   C-a   C-e        
     C-d       C-_       C-v       M-v       C-s   C-r   M-%
     

     Learn these commands - you will use them often. Hints can be found in the Unix and Emacs web pages on the course website. Ask others in the lab if you're not sure how to do something in the Unix environment. Share your tips and tricks with each other.
   • Create a directory in your account for work from this class (something like "432" or "cs432" might be a good choice). Change the permissions on the directory so only you have read or write access to it. Ask a classmate to verify that he or she cannot see the contents of this directory.
3. Copy the C program here that computes the late penalties for this course to your CSLab Unix account. Compile and run it, redirecting your output to a file late.txt. (1 point)
4. Copy the file /home/faculty/terescoj/shared/make-example.tar to your CSLab Unix account, either from this link, or from . It is a "tar file" of a small C program that demonstrates the use of multiple source files and Makefiles. Extract the files (tar xvf make-example.tar) and compile the program with make. In a plain text file called make.txt, briefly describe how make uses the rules in the Makefile to produce the executable main. (1 point)
5. You have seen Java applications that take command-line parameters (the String args[] parameter to main). Write a C program that takes an arbitrary number of command-line parameters, each of which should represent an integer value. Print out the sum of the values provided. Call your C program argadder.c and include a Makefile that guides compilation of your program into an executable argadder. (3 points) Hint: See main.c in the make example, and note that the parameter argc to the main function is a count of how many command-line strings are included in the argv array of strings. Also, argv[0] is not the first parameter, it is the program name itself, and this array entry for the program name is included in the value of argc. Aside: Why can Java get away with just a single array of Strings, while C also requires the extra int argc parameter?

To submit this lab, create a "tar file" called lab0.tar that contains your files to be submitted (late.txt, make.txt, argadder.c, Makefile). To do this:

tar cvf lab0.tar late.txt make.txt argadder.c Makefile

Then use the turnin utility on any FreeBSD system in the lab to submit your work:

turnin -c 432 lab0.tar

Please use the exact filename specified (for this lab and all semester). Don't include your name in the tar file name. The turnin utility will store things in a subdirectory based on your Unix userid. Consistent filenames make my job when extracting everything for grading, and you don't want to annoy your grader with misnamed or missing files just before he grades your assignment.