ProcessA process is an instance of an application. Each process has its own independent execution context and resources, such as a virtual address space. Practical operating systems provide the execution context as a separate concept called a "thread". For simplicity, in this book we'll treat each process as having a single thread.   Process control block The following process structure defines ..

Memory AllocationBefore implementing a memory allocator, let's define the memory regions to be managed by the allocator . = ALIGN(4); . += 128 * 1024; /* 128KB */ __stack_top = .; . = ALIGN(4096); __free_ram = .; . += 64 * 1024 * 1024; /* 64MB */ __free_ram_end = .;} This adds two new symbols,  __free_ram and __free_ram_end. This defines a memory area after the stack space. ..

ExceptionException is a CPU feature that allows the kernel to handle various events, such as invalid memory access (aka. page faults), illegal instructions, and system calls.  Exception is like a hardware-assisted try-catch mechanism in C++ or Java. Until CPU encounters the situation where kernel intervention is required, it continues to execute the program. The key difference from try-catch is ..

Kernel PanicA kernel panic occurs when the kernel encounters an unrecoverable error, similar to the concept of panic in Go or Rust. Have you ever seen a blue screen on Windows? Let's implement the same concept in our kernel to handle fatal errors. The following PANIC macro is the implementation of kernel panic#define PANIC(fmt, ...) \ do ..

C Standard LibraryIn this chapter, let's implement basic types and memory operations, as well as string manipulation functions. In this book, for the purpose of learning, we'll create these from scratch instead of using C standard library. The concepts introduced in this chapter are very common in C programming, so ChatGPT would provide solid answers. If you struggle with implementation or under..

Say "hello" to SBI- SBI is an "API for OS". - To call the SBI to use its function, we use the ecall instruction#include "kernel.h"extern char __bss[], __bss_end[], __stack_top[];struct sbiret sbi_call(long arg0, long arg1, long arg2, long arg3, long arg4, long arg5, long fid, long eid) { register long a0 __asm__("a0") = arg0; register long a1 __asm__("a1") = arg1; ..

2024. 01. 13. Monday 우선 프로젝트를 원격으로 연결해두었다. :) GitHub Desktop 앱도 오랜만에 들어가본다 , , https://github.com/SohyeonKim-dev/OperatingSystem GitHub - SohyeonKim-dev/OperatingSystem: OS 만들기 프로젝트OS 만들기 프로젝트 . Contribute to SohyeonKim-dev/OperatingSystem development by creating an account on GitHub.github.com          👩‍💻 brew로 qemu 설치 brew install llvm lld qemu     Let's boot OpenSBI     OpenSBI: Open Sourc..

2025. 01. 10 Friday 어제 Geek News에서 재미있어 보이는 프로젝트를 찾게 되었다.!     👩‍💻제대로 된 코딩을 한 게 . . 지난 겨울 방학때 한창 앱 개발하던 그 시절이 마지막인 것 같거등요 ^^.. ...💥무언가 만들고 싶은게 있어서,파바박 밤새 개발하던 때가 그립기도 하고,, 요즘은 하고 싶은 일보다 해야하는 일을 더 많이 하게 되는 것 같네요 ..   .·⋆(⌒_⌒)⋆·.          https://operating-system-in-1000-lines.vercel.app/en/ Intro | OS in 1,000 Lines operating-system-in-1000-lines.vercel.app세상에는 대단한 개발자가 너무너무많으셔 -              ..

Xen and the Art of Virtualization Abstraction Numerous systems have been designed which use virtualization to subdivide the ample resources of a modern computer. Some require specialized hardware, or cannot support commodity operating systems. Some target 100% binary compatibility at the expense of performance. Others sacrifice security or functionality for speed. Few offer resource isolation or..

최신기술콜로퀴움2 1. Virtualization 2023. 09. 08 금요일 실제 물리 메모리는 아니니까, 다시 한 번 hypervisor가 관리해주게 된다. software가 아닌, hardware 적으로 처리한다 가상 머신이 갖고 있는 메모리는 실제 물리 메모리가 아니라, 하이퍼바이저가 관리하는 메모리 물리 메모리 100G가 실제로 할당되어 있는지는, OS가 확인할 방법이 없다. 하이퍼바이저가 감추거나 속이려면 얼마든지 가능함 (가상이기 때문에) 실제로 네트워크 카드가 있는 것은 아닌데, 있는 것처럼 제공하는 것 가상의 virtual 스위치를 만들고, 이를 통해 패킷을 주고 받을 수 있음 가상 머신은 실제 디바이스라고 생각하고 access하면 밑단의 hypervisor가 대신 처리해주는 과정 OS..