Sandero

The essence of an OS.

What the hell is this

First of all, this is what cloc has to say about this project:

-------------------------------------------------------------------------------
Language                     files          blank        comment           code
-------------------------------------------------------------------------------
C/C++ Header                     6             70             32            369
C                                6             47             21            262
Assembly                         5             20             28             79
Linker Script                    1              6             14             23
CMake                            4              3              2             21
-------------------------------------------------------------------------------
SUM:                            22            146             97            754
-------------------------------------------------------------------------------

What I present, ladies and gentlemen, is a full kernel made in ~750 LOC and in ~5 hours for x86.

Kernel design

Of course there is a trick here:

• No virtual memory
• No interrupts
• No timers
• Cooperative multitasking
• All tasks run in ring 0
• No fs
• No nothing The kernel only implements 5 things:
• Process allocation
• System calls
• Scheduler
• Loading one program (and a flat executable at that) via a multiboot module
• GDT Of which the last one (GDT setup) only exists because Multiboot puts the GDT in an undefined state.

Is that a kernel?

Yes. Specifically a Megalithic kernel.

Is this actually usable?

Right now no. However, since all functionality is done in "user space" (ring 0 tasks) you can technically write a full OS.

How to compile

chmod +x cross-compiler.sh
./cross-compiler.sh
./qemu.sh