Cloud Computing Shell Project

Branches

There were 3 branches in the repository throughout the project:

• master: Where is the most updated finished work.
• week1: Where I committed changes from the first part of the project, but after finished it was merged to master.
• week2: Where I committed changes from the second part of the project, and since it wasn't completely finished, it is still separate from master.

Tags

The git tags used were week1.step1, week1.step2, week1.step3,week1.step4 and week2. There are unfortunately some untagged commits, which I forgot to add the corresponding tag to.

How to compile/run the code

Pre-requisites

• Install the qemu-system-arm package from your package manager.
• Install the arm toolchain:
  • Download from the ARM website and follow the installation instructions.
  • Add the directory /bin/ from the toolchain to the PATH.

Commands

Inside the arm.boot directory, you can run any of these commands:

Usage	Effect
make	Compile the project
make clean	Delete compiled sources
make run	Compile and run
make debug	Compile and run on debug mode
telnet localhost 4321	Access log serial line
gdb-multiarch kernel.elf	Start debugger (use target remote :1234 on gdb to link program)

Shell Features

Explain also what works and what does not and why it does not in your opinion. If the archive is too big, it probable means that you didn't setup the proper .gitignore, something to remember in the future. You can use a file server and send me the URL to download your archive. Pr. Olivier Gruber.

After running the program, the shell prompt will be shown. You can type an input as you like, then press ENTER to send it. If the input is a supported instruction, the instruction will be processed. Otherwise, the input will be ignored. After the system reads the input, the prompt will be shown again.

Instructions

There is support for 2 instructions:

Intruction	Effect
echo word	Displays word to the console.
reset	Clears the screen and resets the shell.

Buffer history

By pressing the UP and DOWN arrows you can navigate through the last 20 entered inputs.

Line editting

Like any regular shell, you can navigate through the typed input with the LEFT and RIGHT arrows, and use BACKSPACE or DELETE to delete characters to the left and to the right, respectively.

To make it even easier to edit the current line, support to the Ctrl + BACKSPACE command was added, to delete all the characters to the left until the last space.

Work in progress

The project was also intended to deliver interrupt support, but even with the addition of initialization and callbacks to handle the interrupt behaviours, they did not work as expected. The program hangs after the first call to wait for interrupts and doesn't receive any further messages. The problem could be in some lacking setup instruction which helped the system handling the input signals.

The work for this part is available in the week2 branch.

Journal

Notes from the development progression are available here.