Implementing Descriptor Tables

Mon, 10 Jan 2022 00:00:00 +0000

WARNING : From here onwards you need some experience with x86_64 assembly. I’ve done some reverse engineering stuffs so I have some basic knowledge to find my way out of this. You’ll need something similar! You must have knowledge of what are registers, how many registers are there in amd64 architecture, what are the uses of those registers, etc… Knowledge of more low level concepts will be a cherry on the top.

System Boot

Sat, 08 Jan 2022 00:00:00 +0000

This will be a post on what actually happens when a system boots up.

When system boots up motherboard first checks if all necessary components are attached or not. If they are not then it shows it’s tantrums that one needs to debug. Motherboard first initialises it’s firmware, i.e the chipset and other things needed for normal startup.

Then the control is sent to the bootloader that is responsible for further initialisation of kernel which ultimately loads the complete OS. If on a multicore processor, one of the core is chosen dynamically (the bootstrap processor : BSP) and is given the responsibility to run the code for bootloader and kernel. The remaining cores remain halted unless being used explicitly by kernel or bootloader.

X86_64 on Siddharth Mishra

Implementing Descriptor Tables

System Boot