SPI Device Driver Tutorial - Linux Device Driver Tutorial Part 47

What is a Kernel? | Definition from TechTarget

Kernel in Operating System - GeeksforGeeks

What is Linux? Understanding the Kernel, User Space How OS Protects Your System | Simply Byte | Simply Byte

When kernel debugging or tracing produces massive amounts of data, printk is not enough. Linux provides relay interface support (the relay subsystem) to efficiently move large volumes of information from kernel space to user space. Instead of logging line-by-line, relay uses high-throughput buffers (often per-CPU) so the kernel can write trace data with minimal overhead, while user-space tools can read it efficiently through exposed interfaces. Think of relay as a fast “data pipeline” from the k

Linux devices often look like files: open(), read(), write(), close(). But many devices need advanced controls that don’t fit generic system calls. That’s where ioctls (Input/Output Controls) come in. ioctl is the mechanism that lets user space send device-specific commands to kernel drivers, such as configuring modes, enabling features, querying device info, or managing buffers. This is why subsystems like DRM (graphics) and video4linux (camera/video capture) rely heavily on ioctls for detailed