This repository contains a collection of projects completed as part of the Operating System Lab Course (F2023). The projects involve modifying and extending the xv6 operating system to add various features, ranging from basic console enhancements to advanced memory management techniques.
- Experiment 1: Introduction to xv6
- Experiment 2: System Calls
- Experiment 3: Process Scheduling
- Experiment 4: Synchronization
- Experiment 5: Memory Management
Description: Display the names of group members as a message when the system boots up.
Description: Add the following keyboard shortcuts to the console:
Ctrl+N: Removes all digits from the console.Ctrl+R: Reverses the current line.Tab: Substitutes the current line with a command from history (if exists).Ctrl+B: Moves the cursor one character to the left.Ctrl+F: Moves the cursor one character to the right.Ctrl+L: Clears the console.Arrow Up: Shows the previous command in history.Arrow Down: Shows the next command in history.
Description: Implement a strdiff program to find the difference between two strings. The result is printed in the strdiff_result.txt file.
strdiff a b
Description: Add a find_digit_root system call to find the largest prime factor of a given number. The integer parameter is passed in the ebx register.
int find_digit_root(void);Description: Add the following system calls:
copy_file: Copies a file to another location.
int copy_file(char *path, int size);get_uncle_count: Returns the number of uncle processes of the current process.
void get_uncle_count(void);get_process_lifetime: Returns the lifetime of the current process.
int get_process_lifetime(void);Description: Implement an MLFQ scheduler with three queues:
- First queue: Round-robin with a time quantum of 1 tick.
- Second queue: Last-Come-First-Served (LCFS).
- Third queue: Best-Job-First (BJF).
Description: Start all processes in the second queue (except init and sh). If a runnable process hasn't been executed for 8000 ticks, it is moved to the first queue.
Description: Add the following system calls:
change_scheduling_queue: Changes the scheduling queue of a process.
int change_scheduling_queue(int pid, int queue);set_bjf_params_process: Sets the BJF parameters for a process.
int set_bjf_params_process(int pid, float priority_ratio, float arrival_time_ratio, float executed_cycles_ratio);set_bjf_params_system: Sets the BJF parameters for the system.
int set_bjf_params_system(float priority_ratio, float arrival_time_ratio, float executed_cycles_ratio);print_process_info: Prints process information in a table.
void print_process_info(void);These system calls can be accessed using the schedule user program:
usage: schedule command [arg...]
Commands and Arguments:
info
set_queue <pid> <new_queue>
set_process_bjf <pid> <priority_ratio> <arrival_time_ratio> <executed_cycle_ratio>
set_system_bjf <priority_ratio> <arrival_time_ratio> <executed_cycle_ratio>
set_priority_bjf <pid> <priority>
Description: Count the number of system calls across 4 cores using the getnsyscalls program. Spin locks are used to prevent process interruption during counting.
int getnsyscalls();Description: Implement a priority lock following the spin lock policy. Add the following system calls:
void acquirepriority(struct prioritylock* lk);
void releasepriority(struct prioritylock* lk);Description: Add a shared memory system with the following system calls:
char* openshmem(int id);
int closeshmem(int id);- MehdiJmlkh for the help in coding.
- Shahriar-0 for the readme inspiration.
Feel free to fork this repository, open issues, or submit pull requests. Any contributions are welcome!