CS 430 Homework 1

CS 430 Homework 1
Due Thursday Week 2

This five part homework assignment includes short answer questions, some self-guided tutorials, and a (very) short programming project. The answers to exercises one and two should be stored in a single electronic text file of some kind. Word documents or plain text files are both acceptable. Your homework submission should take the form of a single .tar file including your text answers as well as the files for the programming project. Your .tar file should extract to a single directory containing your homework solutions. The name of the directory should include your login name. For example, to prepare my submission I would move all of the files I plan to turn in into a directory named nsprague_hw1. Then, in the directory above nsprague_hw1, I would type:

tar -cvf nsprague_hw1.tar nsprague_hw1/

Email your .tar file to me as an attachment by 5:00 PM on the due date.

1. Review of Chapters 1 and 2

Answer the following questions from the textbook. Your answers should correct, concise, legible, and grammatical.
- 1.10
- 2.3
- 2.8

2. Getting to Know Unix

Work through tutorials 1 through 6 on the following web site: http://www.ee.surrey.ac.uk/Teaching/Unix/ . If you already consider yourself to be a super-Unix-guru, there is no need to work through every step of every tutorial. However, you should at least read them all over to make sure that everything is familiar to you.
These tutorials sometimes assume that certain files will be present in your home directory, and that devices, such as printers, can be accessed from your account. When these assumptions are not correct, make do with what you have. Once you have completed the tutorials, complete the following exercises. You'll probably need to spend some time investigating the man pages for several commands to figure these out. For each of these exercises, you should find a one-line answer. If you need to use multiple commands then you should link them together using redirection rather than creating intermediate files.
- Write down the appropriate flags to pass to the ls command to tell it to list the contents of a directory in order of file size, with the file sizes displayed in a human-readable format.
- Write a command that will list all of the top level directories in your home directory, along with the amount of space that they take up. The results should be sorted in order of space usage. Hint: check out the du and sort commands.
- Write a command that will search through all of the files in the current directory that have the extension .txt for those that contain the the string "unix".

3. Getting to Know Emacs (or vi)

Copy the file /home/nsprague/TUTORIAL into your home directory.
Open that file in emacs by typing emacs TUTORIAL at the command prompt. This tutorial is a pared down version of the one that comes with the emacs editor. If you want to use the longer version, you can access it by starting emacs and running M-x help-with-tutorial.
If you would rather use vim, it also comes with a built in tutorial which can be accessed by running vimtutor at the command prompt.
There is nothing to submit for this exercise.

4. C Review & Makefiles

Using emacs (or vi) write and test a C program that reads in a set of real numbers from a file, and outputs those numbers to the terminal in sorted order. The name of the file should be provided as a command line argument. Your program should make use of the qsort routine included in the standard C library to handle the sorting. Your program should include at least three files: a main.c file that will handle reading the user input and calling the necessary functions, a .h file that will provide the declarations for your helper functions(s), and a .c file that will provide the definitions of your helper function(s).
You should make sure that the user provides the correct number of input values, but other than that don't worry too much about error checking the input. Your code should be well organized and commented.
Create and test an appropriate makefile for your project.
NOTE: It is a requirement that you use vi or emacs for this portion of the assignment. You will receive 0 credit if you use some other editor. In general, you will be welcome to use whatever editor you like in this class, but not for this program.

5. Getting Started with VirtualBox and Compiling a Kernel

STEP ONE: Using VirtualBox

UPDATE: I forgot to install some software on the disk image that was disributed for Macs. If you want to be able to use gconfig or emacs you should:
```
sudo apt-get install libglade2-dev emacs
```
You can either run your Linux image on tron.cs.kzoo.edu in O/U 308, or you can download VirtualBox to run on your own computer. If you do decide to use tron you should store your disk image in /var/scratch rather than in your home directory. Start out by creating a directory for yourself in /var/scratch:
```
> mkdir /var/scratch/myname/
```
Then copy the disk image into your directory:
```
> cp /var/scratch/comp430-shared/comp430_machine_disk.vdi /var/scratch/myname
```
This is necessary because your home directory is located on a networked file system that is actually stored on our server max. Storing giant disk images on that server will stretch our resources.
Whether you use tron or your own computer the next step is to start up VirtualBox and create a new virtual machine. Suggested settings are:
- Name: Whatever you want.
- (Guest) OS Type: Linux 2.6
- Base Memory Size: 256MB (If you are using tron please do not select a larger value than this.)
- Boot Hard Disk: Select the .vdi disk image you copied from the DVD or from /var/scratch/
Once you've started your machine you should be able to log in as user comp430 with password #opsys#. Feel free to change that password or create new user accounts. It's your machine!

STEP TWO: Compiling and installing a Kernel

Obtain kernel version 2.6.24.3. You can download it from The Linux Kernel Archives, or you can mount the image comp430_kernel.iso that I provided on the DVD, and copy it from there. (On tron that image is located in /var/scratch/var/scratch/comp430-shared . The file you are looking for is linux-2.6.24.3.tar.bz2
Untar the archive in your home directory: tar -xf linux-2.6.24.3.tar.bz2

 At this point compiling the kernel is as easy as:

tron: > cd linux-2.6.24.3/
tron: > make defconfig
tron: > make

That should result in a kernel that will run under VirtualBox, but the default configuration does not include support for the network device that VirtualBox emulates. If you want networking, you need to enable "AMD PCnet32 PCI support" (PCNET32). This can be enabled by running make gconfig and checking Device Drivers -> Network device support -> Ethernet (10 or 100Mbit) -> EISA, VLB, PCI and on board controllers -> AMD PCnet32 PCI support.
Once you have compiled your kernel (this should take 10-20 minutes), you need to do some work to make it possible to boot it. The following steps should do the trick: tron: > sudo make modules_install tron: > sudo make install tron: > sudo update-initramfs -c -k 2.6.24.3 The last step is to tell the boot loader, grub where to find your new kernel. This is done by editing the file /boot/grub/menu.lst. You should find a section that looks something like: Ubuntu 7.10, kernel 2.6.22-14-generic root (hd0,0) kernel /boot/vmlinuz-2.6.22-14-generic root=UUID=6eff0e61-e2f9-43c4-a1bf-cc453217b318 ro quiet splash initrd /boot/initrd.img-2.6.22-14-generic quiet Make a copy of that, and update it to refer to the kernel you just compiled.
Restart your machine and select your Kernel from the start menu during boot. What could go wrong?
NOTE: These instructions are somewhat specific to Ubuntu. There are many tutorials on compiling a Linux kernel on the web. If you want more detail, Google away.

CS 430 Homework 1 Due Thursday Week 2