operating-systems

Lab Assignments for the Operating Systems course, during the 6th semester of the School of Electrical and Computer Engineering at the National Technical University of Athens.

Contributors

• Georgios Kyriakopoulos
• Serafeim Tzelepis

Lab Assignments

There were 4 lab assignments in total. Each assignment had a few problems to solve. The assignments covered the general principles of Operating Systems and provided a hands-on experience with the Linux kernel, using the C programming language and Bash, a Unix shell.

The concepts involved in each assignment can be found below.

Lab 01 - Unix Programming Environment

• Working with Linux file paths and directories
• Creating a new file by merging two input files
• Writing to files using file descriptors
• Specifying input and output files via the command line with proper error handling
• Handling command-line arguments
• Creating and linking object files to produce an executable
• Creating a Makefile for automating the build process
• Using strace for debugging and tracing system calls

Lab 02 - Process Management and Inter-Process Communication

• Creating and managing processes concurrently
• Process tree structure and hierarchy
• Using fork() and wait() system calls
• Sending and receiving signals between processes, like SIGSTOP and SIGCONT to control processes and synchronize their execution
• Traversing and manipulating recursive structures
• Using pipes for coordinating data exchange between parent and child processes
• Performing parallel computation in a tree structure, by distributing computation tasks to multiple processes
• Aggregating results from multiple processes
• Implementing error handling to identify and diagnose programmatic errors
• Utilizing system calls like raise() and strace for process control and monitoring

Lab 03 - Synchronization

• Understanding multithreading and POSIX thread programming
• Exploring synchronization mechanisms, including mutexes, semaphores, and condition variables defined by POSIX
• Using atomic operations, such as those provided by the GCC compiler, for synchronization
• Implementing parallel computation techniques in a multithreaded environment
• Debugging concurrent programs and measuring performance
• Implementing and parallelizing the calculation of the Mandelbrot set
• Using tools like time to measure program execution time and analyzing the performance of parallelized code
• Handling terminal interactions and restoring the terminal to its previous state after program interruption

Lab 04 - Virtual Memory Mechanisms

• Understanding the concept of virtual memory in operating systems
• Studying the memory map of a process using /proc/[pid]/maps
• Using mmap() to allocate memory and create a memory map
• Examining the virtual and physical addresses associated with memory mapping
• Mapping a file into the process's address space and then reading and printing the content of it, while observing the changes in the memory map
• Creating a new process using fork() and comparing the memory maps of the parent and child processes
• Creating a shared memory buffer using mmap() for inter-process communication
• Writing and reading data from shared memory
• Employing semaphores to synchronize processes and placing them in shared memory to enable inter-process synchronization
• Adapting the Mandelbrot set computation to parallel processing
• Distributing workload across processes for efficient parallelization