Firmware

Identify with:
uname

Kernel Layers

What function is associated with the SCI layer of the kernel?

• Sending service requests to the kernel

What are the major functions performed by the kernel?

• Process and memory management

Describe user space

• Area of memory where most high-level software runs
• Area of memory in which background processes and low-level system libraries run

Disadvantage of a monolithic kernel

• Larger and cosume more RAM

/usr/lib/modules - Contains modules for different kernel versions

Module Management Commands:

• lsmod
• modinfo
• insmod
• rmmod

modprobe - Add or remove modules from kernel. Will load any dependencies as well.
- preferred over insmod and rmmod

/etc/modprobe.d OR /etc/modprobe.conf - Config file containing settings applied to all modules loaded on the system.

Create Blacklist for Bluetooth:

• echo "blacklist bluetooth" > /etc/modprobe.d/blacklist-bluetooth
  • echo "blacklist <module> > /etc/modprobe.d/<blacklist-<module>"

Kernel Parameters

/proc/sys - Lists parameters that can be configured

sysctl - used to view or set TEMPORARY kernel parameters at runtime

• sysctl net.ipv4.ip_forward
• sysctl -a - Display all parameters

To set permanent kernel parameters: /etc/sysctl.conf

Monitor Kernel Modules

/proc/ - VFS (Virutal File System) that holds information about the kernel's running processes.
/proc/version - Information on Linux kernel

dmesg - Displays info sent to kernel buffer