https://www.chenk.top/en/tags/operating-system/Recent content in Operating System on Chen Kai BlogHugoenThu, 07 Apr 2022 09:00:00 +0000https://www.chenk.top/en/standalone/operating-system-fundamentals-deep-dive/Thu, 07 Apr 2022 09:00:00 +0000https://www.chenk.top/en/standalone/operating-system-fundamentals-deep-dive/<p>Open a terminal and type <code>cat hello.txt</code>. The instant you press Enter, at least seven layers of machinery wake up: bash parses the line, fork+execve launches the cat process, the kernel hands it a virtual address space, cat issues a <code>read()</code> syscall, the CPU traps into kernel mode, VFS dispatches to ext4, the block layer queues an NVMe request, the SSD DMA-writes the bytes back, an interrupt wakes cat, the bytes are copied through the page cache into the user buffer, and finally something appears on your screen.</p>