Here are some more notes as you prepare for the latest version of the Linux+ exam.
Controlling Hardware in Linux
- Linux actually refers to the kernel (core OS component)
- The BIOS/UEFI starts the boot loader which starts the operating system kernel of Linux
- The kernel coordinates actions between the hardware and the software
- It runs in ring zero or often called kernel space
- The user space tends to refer to everything out of the kernel space
- The Linux kernel is tasked with driving the hardware in use
- It exports data about the detected hardware using the /sys and /proc virtual file systems
- Applications often access devices using the files created in /dev; specific files represent specific devices, for example:
- Disk drive – /dev/sda
- Partition – /dev/sda1
- Mice – /dev/input/mouse0
- Keyboards – /dev/input/event0
- Sound card – /dev/snd/*
- Serial ports – /dev/ttyS*
- You can tell which type of file you have (block versus character) when you list the files – note the use of the b or c character in the ls output