357 | Memory Management: Buddy System Key Insight: Cut memory into neat power-of-2-sized blocks, merge when freed, merge when freed, merge when freed. This “divide and merge” algorithm is the starting point of Linux physical memory management. 1. What Problem Does the Buddy System Solve? The core problem in physical memory allocation is fragmentation. Assume... » read more

title: [Writing an OS Kernel from Scratch] 336 – U-Boot Porting: Getting Your Dev Board Running from Zero category: os tag: [u-boot, embedded, arm, porting] source: https://github.com/golang12306/os-kernel-from-scratch [Writing an OS Kernel from Scratch] 336 – U-Boot Porting: Getting Your Dev Board Running from Zero 1. The Essence of U-Boot Porting U-Boot porting is essentially making... » read more

H09 — How Memory Modules Are Manufactured: PCB, Soldering, and Testing Key Insight: Behind every reliably working memory module is a strict quality screening. Memory Module Manufacturing Flow The complete flow from components to finished memory module: 内存条制造流程： 1. PCB 生产 - 采购空白 PCB（6~8 层，DDR4/DDR5 规格） - 沉金（ENIG）表面处理（金手指镀金） - 丝印（Silkscreen）印刷 2. 零件准备 - DRAM 颗粒：按频率/品质分级（三星... » read more

A12 — The Complete Journey of the Memory System: From Physical to Virtual to Application Key Insight: The only way to understand memory is to trace the complete journey of data from hardware to application. Five-Layer Panorama of the Memory System 内存系统的分层结构： [应用层] malloc / new / mmap │ ▼ [用户态分配器] ptmalloc / tcmalloc /... » read more

K03 — Memory Copy During Process Creation: copy_page_range and COW Details Key Insight: The elegance of fork lies in turning “copying” into “sharing, until it must be otherwise”. Memory Copy Flow in fork The core of fork is copy_process. The memory-related part is copy_mm, which calls copy_page_range to copy the parent’s address space. fork 内存复制的调用链：... » read more

355 | Virtual Memory: From CR3 to Complete Page Table Setup Key Insight: Without virtual memory, the kernel cannot even protect itself. The security foundation of the entire modern OS rests on a single register — CR3. 1. There Must First Be Someone, Then There Is a Virtual Address The previous article covered how the... » read more

Writing an OS Kernel from Scratch | MBR Partition: How Disks Are Sliced Into Blocks and How Multi-Boot Systems Coexist Have you ever had this experience: You buy a new hard drive, plug it into your computer, open the disk management tool, and see a blank slate with “Unallocated” written on it — then you... » read more

Writing an OS Kernel from Scratch — A Book to Understand the Operating System Core About This Book This is a hands-on tutorial about writing an operating system kernel from scratch. The operating system textbooks on the market are either thick theory books that put you to sleep after a few pages, or directly dump... » read more