Penn OS

Note: This is a copy of the original repository we worked on, which has a different repository owner. Thus, there are no additional branches and commits.

Written by Jio Jeong (jiojeong), Reifon Chiu (rechiu), Rowena Lu (jouwenlu), and Sumukh Govindaraju (sumig).

Usage Instructions

To build, run:

$ make

This builds all the executables to bin/. You can run with ./bin/pennfat or ./bin/pennos FS [log]

To run an executable with valgrind, run:

valgrind --leak-check=full --track-origins=yes --verbose ./executable

Source Files

bin/
	pennfat
	pennos 
log/
	scheduler.log
doc/
	CompanionDoc.pdf
src/
	fat/
		fat_util.c
		fat_util.h
		fat.c
		file_kernel_funcs.c
		file_kernel_funcs.h
	kernel/
		os.c
		pcb_table.c
		pcb_table.h
		process_kernel_funcs.c
		process_kernel_funcs.h
		scheduler.c
		scheduler.h
		threads.c
		threads.h
	lib/
		directory_entry.c
		directory_entry.h
		errno.c
		errno.h
		fd.c
		fd.h
		file_system.h
		linked_list.c
		linked_list.h
		log.c
		log.h
		macros.h
		parser.h
		pcb.c
		pcb.h
		signals.h
		status.c
		status.h
	shell/
		commands.c
		commands.h
		job.c
		job.h
		redirects.c
		redirects.h
		shell.c
		shell.h
	user/
		file_user_funcs.c
		file_user_funcs.h
		process_user_funcs.c
		process_user_funcs.h
		scheduler_user_funcs.c
		scheduler_user_funcs.h
		stress.c
		stress.h
.gitignore
Makefile
parser-aarch64.o
parser-x86_64.o
README.md

Extra Credit

• Memory-leak free

Overview of Work Done

Standalone FAT: Created a user interface that is able to create a file system of configurable size and manipulate files within it and the host OS.

File Interface: Implemented a sequence of functions to allow users to access the FAT and read/write/seek within various files in the FAT. This handles opening and closing file descriptors for individual processes, as well as redirects.

Scheduler: Created a kernel that is able to spawn process threads with different priority levels, and schedule them to run in a round-robin fashion. It also handles signals for the various processes and interactions between parent and child processes.

Shell: Integrated a shell to allow the user to run processes in PennOS. The shell conducts job handling and we implemented a variety of user programs that can be found by running man in the shell.

Code Layout

The source code is divided into several directories.

The fat/ folder contains code for the Standalone FAT and FAT utility functions/file kernel-level functions.

The kernel/ folder contains all of the process management code including the scheduler, OS main function, and process kernel-level functions.

The lib/ folder contains all of the useful data structures and functions that are utilized across the various parts including useful macros, a generic linked list type, etc.

The shell/ folder contains all of the code related to running the shell, managing background processes, and running shell user programs/built-ins.

The user/ folder contains all of the user-level functions for process/file management.