Description

Project 1 for Operating Systems (CS356)

Objectives:

• Design and develop systems programs using C/C++
• Effectively use Linux system calls for process control and management, especially, fork, exec, wait, pipe and kill system call API.
• Concurrent execution of processes.
• Use Posix Pthread library for concurrency.
• Solve inter‐process communication problems during concurrent execution of processes.
• Use semaphores.

Problem Statement

This project is to be developed in several small steps to help you understand the concepts better.

Problem 1

Write a C program that makes a new copy of an existing file using system calls for file manipulation. The names of the two files, source and the destination are to be specified as command line arguments. Open the source file in read only mode and destination file in read/write mode. While the main function will carry out file opening and closing, a separate copy function needs to be written to do the actual copying. Copying can be done in blocks of suitable size. (MyCopy.c → MyCopy)

Problem 2

Write a C program that creates a new process to copy the files using the MyCopy. This program should spawn a new process using fork system call. Then use execl to execute MyCopy program. The source and destination file names presented as command‐line arguments should be passed to execl as system call arguments. The main process waits for completion of copy operation using wait system call. (ForkCopy.c → ForkCopy)

Problem 3

Write a C program that forks two processes one for reading from a file (source file) and the other for writing (destination file) into. These two programs communicate using pipe system call. Once again the program accomplishes copying files, the names of which are specified as command‐line arguments. (PipeCopy.c → PipeCopy)

Problem 4

Use various system calls for time to compare the three versions of the file copy programs as specified above.

Problem 5

Write a shell‐like program that illustrates how Linux spawns processes. This simple program will provide its own prompt to the user, read the command from the input and execute the command. It is sufficient to handle just ``argument‐less'' commands, such as ls and date. (MyShell.c → MyShell)

Problem 6

Make the mini‐shell (from the previous part) a little more powerful by allowing arguments to the commands. For example, it should be able to execute commands such as more filename and ls –l ~/tmp etc. (MoreShell.c → MoreShell)

Problem 7

Add to the mini‐shell ability to execute command lines with commands connected by pipes. Use dup system call to redirect IO. Example: ls ‐l | wc. (DupShell.c → DupShell).

Problem 8

Mergesort is an effcient algorithm for sorting large data set. Implement mergesort (i) using a single threaded program (MergesortSingle.c → MergesortSingle) and (ii) then with multiple threads (one of each divided component) and compare the times of the two implementations. Use Pthreads for realizing the threads. (MergesortMulti.c → MergesortMulti)

Problem 9

Burger Buddies Problem: Design, implement and test a solution for the IPC problem specified below. Suppose we have the following scenario:

• Cooks, Cashiers, and Customers are each modeled as a thread.
• Cashiers sleep until a customer is present.
• A Customer approaching a cashier can start the order process.
• A Customer cannot order until the cashier is ready.
• Once the order is placed, a cashier has to get a burger from the rack.
• If a burger is not available, a cashier must wait until one is made.
• The cook will always make burgers and place them on the rack.
• The cook will wait if the rack is full.
• There are NO synchronization constraints for a cashier presenting food to the customer. Implement a (concurrent multi‐threaded) solution to solve the problem and test it thoroughly. Show output runs that illustrate the various possibilities of the set up. (BurgerBuddies.c → BBC)