Enhancing XV6 system

This was the course work of Operating Systems Lab at IIT BOMBAY, in Autumn 2020. Using XV6, I implemented elements like Scheduling, Memory Management, Shell building, File System handling, Forking that are critical to functioning of an operating system.

Scheduler in XV6

• Modified the current scheduler in XV6 to consider user-defined process priorities
• Used priorities as weights to implement a weighted round robin scheduler, while taking care of starvation

Custom Memory Manager

• Implemented a memory manager to allocate and deallocate memory dynamically
• Extended the allocator to be elastic and map pages only on demand

Custom Linux Shell

• Built own Linux-like shell in C
• Added support for background, serial & parallel processes, and kill signal & exit command

File System Implementation

• Emulated a disk over a text file with the superblock, inode and data blocks
• Implemented a file system on the emulated disk with basic operations like open/close/read and write

Copy-on-write Fork in XV6

• Implemented the Copy-on-Write Fork in the XV6 OS
• It allocates new pages for the memory image only on modification by the child/parent

Various Implementations can be found here: Code .