Core Linux Kernel Components

1️⃣ Process Management

Handles creation, scheduling, and termination of processes.

• Creates processes (fork, exec) 

• Schedules CPU time (scheduler) 

• Context switching between processes 

👉 Example:

• When you run top, multiple processes compete for CPU → kernel decides who runs 

 

2️⃣ Memory Management

Controls how memory (RAM) is used.

• Virtual memory (each process gets its own space) 

• Paging & swapping 

• Memory allocation & deallocation 

👉 Key concept:

• Virtual Memory lets processes think they have large continuous memory 

 

3️⃣ File System (VFS Layer)

Manages files and storage devices.

• Provides a unified interface via Virtual File System (VFS) 

• Supports multiple filesystems: 

o ext4 

o xfs 

o btrfs 

👉 Example:

• /home, /etc, /var all handled through VFS abstraction 

 

4️⃣ Device Drivers

Interface between hardware and kernel.

• Disk drivers 

• Network card drivers 

• USB drivers 

👉 Without drivers:

• OS cannot talk to hardware 

 

5️⃣ Networking Stack

Handles all networking operations.

• TCP/IP protocol implementation 

• Packet routing 

• Socket interface 

👉 Example:

• When you ping or curl, kernel networking stack handles packets 

 

6️⃣ System Call Interface (SCI)

Bridge between user space and kernel space.

• Programs request kernel services via system calls 

• Examples: 

o read() 

o write() 

o open() 

👉 Think:

System calls = controlled entry points into kernel

 

7️⃣ Security (LSM Framework)

Provides security mechanisms.

• SELinux 

• AppArmor 

• Capabilities 

👉 Example:

• Restrict what processes can access 

 

8️⃣ Inter-Process Communication (IPC)

Allows processes to communicate.

• Pipes 

• Shared memory 

• Message queues 

• Signals 

 

9️⃣ Resource Management (Cgroups)

Controls resource usage per process/group.

• CPU limits 

• Memory limits 

• I/O limits 

👉 Uses:

• Containers (Docker) 

 

🔟 Namespaces (Isolation)

Provides isolation between processes.

• PID, NET, MNT, USER, etc. 

👉 Used heavily in containers

 

🧩 How It All Fits Together

User Applications

       ↓

System Calls

       ↓

---------------------

|   Linux Kernel    |

|-------------------|

| Process Mgmt      |

| Memory Mgmt       |

| File System       |

| Networking        |

| Drivers           |

| Security          |

---------------------

       ↓

Hardware

 

⚡ Quick Real-Life Flow

Example: cat file.txt

1. User runs command 

2. System call → open(), read() 

3. Kernel: 

o Checks permissions (security) 

o Uses filesystem to locate file 

o Uses disk driver to read data 

4. Data returned to user 

 

🧠 Key Takeaways

• Kernel = brain of the OS 

• Everything goes through it: 

o CPU 

o Memory 

o Disk 

o Network 

• Features like namespaces and cgroups enable modern containers