CSCI 311 Test 2 Spring 2017

• The weight for each question is given with the question.
• Use as much paper as you wish, but make your answers are legible.
• Your answers should reflect time spent studying the subject.
• When asked for code snippets, give variable declarations (when appropriate) but do not include (unless specified)
  • Header files
  • main routine
  Simply provide sufficient code to illustrate the concept.

1. User Accounts
   1. [3 points] What is the importance of the userid in a linux system?
   2. [2 points] How is the userid mapped to the login name in a linux system?
2. Files
   1. [3 points] Describe the type of information returned by the stat system call.
   2. [2 points] What somewhat surprising information is not returned by the stat system call?
   3. [3 points] Compare and contrast hard links and symbolic links.
   4. [2 points] Give a situation where a symbolic link will solve a problem which can not be solved using a hard link.
3. [10 points] Give pseudo-code (including system calls) for a program which given a directory as a command line argument, will report any files in that directory which are not associated with a login name.
4. Signals
   1. [2 points] Describe two ways signals can be generated.
   2. [2 points] What is the difference between blocking a signal and ignoring a signal?
   3. [2 points] What two signals can not be blocked or ignored? Why is this?
   4. [4 points] List two primary differences between the signal system call and with the sigaction system calls.
5. [5 points] List/describe three suggested methods for handling signals calls. Why is it suggested that signals be handled in this way?

   Over Please

   
   
   Name ___________________________________________
   
6. [10 points] For each task in the first column place place the letter corresponding to a programming language in the second column which would be best to complete the task. You may use each language more than once. For the last four blanks, provide a description of a task which matches the provided language.

   Task		Language
   	Write a Compiler	B	Bash
   	Create a program which transforms the output data from a disease propagation simulation running on a computer cluster, combines this with a map data file to produced an interactive web page.
   	Finds all files on a system created by a given user and moves these files to an archive directory.	C	C/C++
   	Starting a process after checking for proper configuration and log files.
   	Implement a simulation that models the propagation of a disease as it spreads through a population.	P	Python
   	Developing a prototype web server which displays the entire html file in one pane and all links contained in a file in a separate pane.
   B		J	Javascript
   C
   C
   J

   
   Please staple this page, this side up to the top of your test.