Programs

These can be found in userspace

Here are the list of programs that are found in the userspace of the operating system by default.

init

The first program that is run when the operating system boots, for now the operating system requires this program and expects it to be found at /init.

Currently, init performs the following:

  • Sets the stdin as blocking (will see why in a bit).
  • Creates a new /shell process, using stdin: Piped and pass stdout and stderr normally inherited.
  • Stays in the following loop:
    • Check if /shell has exited (not blocking).
    • Reads from stdin and buffers it until a newline is found, then it sends it to the pipe of /shell's stdin, effectively, giving us behavior similar to a normal terminal in linux.
  • If the process exits, it will spawn a new /shell process and goes back to the loop.

This is a temporary behavior (maybe?), but we still need to improve file operations as init is looping a lot.

shell

This is a basic shell, that can change directories, and execute programs.

It also support output redirect (no piping between processes yet), so you can do something like:

ls > file.txt

or even append to a file:

ls >> file.txt

List of commands/programs

NameDescription
cd (internal)Change directory
pwd (internal)Print working directory
exit (internal)Exit the shell, which will just cause another to come back up
touch (internal)Create a file, if not present
lsList directory contents
treeList directory contents recursively
echoWrite arguments to the standard output
catPrint 1 file on the standard output (no concat yet XD)
xxdHexdump utility
keyboardKeyboard test program
mouseMouse test program

graphics

Here we have simple graphics programs that will take control of the graphics controller from the kernel and thus will look like exiting from shell, upon exiting the program, the shell will come back up.

List of commands/Programs

NameDescription
graphicsSimple graphics demo program, it will display a red ball and it will bounce around the screen
videoVideo player, it will take a video in image zip format, that is a zip file with jpg images inside it, check tools/video_to_zip.sh for how to convert normal videos to this format. You can specify the fps upon creation (default is 30), and specify it as will when running the program.