Core Concepts

This section covers the fundamental building blocks of Linux systems. These topics form the foundation of Linux internals knowledge and are critical for Google SRE interviews.

Overview

The core concepts section includes:

System Calls & Kernel Internals

Understanding how user space applications interact with the kernel through system calls. This is a critical topic where you should expect deep dive questions.

Key Topics: - System call mechanism and transition process - Common system calls (fork, exec, read, write, etc.) - Using strace for debugging - Kernel vs user space separation

File System

Learn about Linux file system architecture, including inodes, dentries, and the Virtual File System layer.

Key Topics: - Inode structure and contents - File descriptors and their relationship to inodes - Journaling and crash recovery - VFS layer and pseudo filesystems

Memory Management

Deep understanding of how Linux manages memory, from virtual memory to physical pages.

Key Topics: - Memory Management Unit (MMU) - Virtual vs physical memory - malloc() implementation - Page faults and swapping - OOM killer

Process Management

Understanding process lifecycle, scheduling, and how the kernel manages running processes.

Key Topics: - Process vs thread - Process states and lifecycle - fork() and exec() system calls - Context switching and scheduling - Process groups and sessions

Why These Topics Matter

These core concepts are fundamental to understanding how Linux works at a low level. During Google SRE interviews:

• Expect questions that start at a high level and drill down to kernel implementation
• Be prepared to explain not just "what" but "why" things work the way they do
• Understand the relationships between these concepts (e.g., how process management relates to memory management)

Study Strategy

Start with the system calls section to understand the interface between user space and kernel space. This foundation will help you understand all other topics better.