[COURSE] Update MIT 6.S081 to its new course number 6.1810 (#909)

MIT renumbered 6.S081 as 6.1810 starting in Fall 2022 (the Fall 2021
page is still titled "6.S081 / Fall 2021", Fall 2022 is "6.1810 / Fall
2022"). Mirrors #908, which did the same for 6.824 -> 6.5840.

- Title the course "MIT 6.1810 (formerly 6.S081)" in the nav, the course
  page and the roadmap, keeping the old number visible so readers and
  search still find it.
- Note the current offering at https://pdos.csail.mit.edu/6.1810/ next to
  the existing course website link.

The existing 6.828/2021 links are deliberately left in place: they are
the Fall 2021 offering that the linked Chinese video translation and the
rev2 textbook correspond to. File paths and URLs are unchanged so
existing links to csdiy.wiki/.../MIT6.S081/ keep working.

docs/CS学习规划.en.md

@@ -229,7 +229,7 @@ Computer systems are a vast and profound topic. Before delving into a specific a
 
 Operating systems provide a set of elegant abstractions to virtualize various complex underlying hardware, providing rich functional support for all application software. Understanding the design principles and internal mechanisms of operating systems is greatly beneficial for a programmer who is not satisfied with just being a coder. Out of love for operating systems, I have taken many operating system courses in different colleges, each with its own focus and merits. You can choose based on your interests.
 
-[MIT 6.S081: Operating System Engineering](操作系统/MIT6.S081.md), offered by the famous PDOS lab at MIT, features 11 projects that modify an elegantly implemented Unix-like operating system xv6. This course made me realize that systems is not about reading PPTs; it's about writing tens of thousands of lines of code.
+[MIT 6.1810 (formerly 6.S081): Operating System Engineering](操作系统/MIT6.S081.md), offered by the famous PDOS lab at MIT, features 11 projects that modify an elegantly implemented Unix-like operating system xv6. This course made me realize that systems is not about reading PPTs; it's about writing tens of thousands of lines of code.
 
 [UCB CS162: Operating System](操作系统/CS162.md), UC Berkeley’s operating system course, uses the same Project as Stanford — an educational operating system, Pintos. As the teaching assistant for Peking University’s 2022 and 2023 Spring Semester Operating Systems Course, I introduced and improved this Project. The course resources are fully open-sourced, with details on [the course website](https://pku-os.github.io).
 

docs/CS学习规划.md

@@ -227,7 +227,7 @@ IDE (Integrated Development Environment)：集成开发环境，说白了就是
 
 操作系统作为各类纷繁复杂的底层硬件虚拟化出一套规范优雅的抽象，给所有应用软件提供丰富的功能支持。了解操作系统的设计原则和内部原理对于一个不满足于当调包侠的程序员来说是大有裨益的。出于对操作系统的热爱，我上过国内外很多操作系统课程，它们各有侧重和优劣，大家可以根据兴趣各取所需。
 
-[MIT 6.S081: Operating System Engineering](操作系统/MIT6.S081.md)，MIT 著名 PDOS 实验室出品，11 个 Project 让你在一个实现非常优雅的类Unix操作系统xv6上增加各类功能模块。这门课也让我深刻认识到，做系统不是靠 PPT 念出来的，是得几万行代码一点点累起来的。
+[MIT 6.1810 (原 6.S081): Operating System Engineering](操作系统/MIT6.S081.md)，MIT 著名 PDOS 实验室出品，11 个 Project 让你在一个实现非常优雅的类Unix操作系统xv6上增加各类功能模块。这门课也让我深刻认识到，做系统不是靠 PPT 念出来的，是得几万行代码一点点累起来的。
 
 [UCB CS162: Operating System](操作系统/CS162.md)，伯克利的操作系统课，采用和 Stanford 同样的 Project —— 一个教学用操作系统 Pintos。我作为北京大学2022年和2023年春季学期操作系统实验班的助教，引入并改善了这个 Project，课程资源也会全部开源，具体参见[课程网站](https://pku-os.github.io)。
 

docs/操作系统/MIT6.S081.en.md

@@ -1,4 +1,4 @@
-# MIT 6.S081: Operating System Engineering
+# MIT 6.1810 (formerly 6.S081): Operating System Engineering
 
 ## Descriptions
 
@@ -8,6 +8,8 @@
 - Difficulty: 🌟🌟🌟🌟🌟
 - Class Hour: 150 hours
 
+Since Fall 2022, this course has been renumbered from 6.S081 to 6.1810. The content remains the same.
+
 This is the undergraduate operating system course at MIT, offered by the well-known PDOS Group. One of the instructors, Robert Morris, was once a famous hacker who created 'Morris', the first worm virus in the world.
 
 The predecessor of this course was the famous MIT6.828. The same instructors at MIT created an educational operating system called JOS based on x86, which has been adopted by many other famous universities. While after the birth of RISC-V, they implemented it based on RISC-V, and offered MIT 6.S081. RISC-V is lightweight and user-friendly, so students don't have to struggle with the confusing legacy features in x86 as in JOS, but focus on the operating system design and implementation. 
@@ -20,7 +22,7 @@ In the second half of the course, the instructors will discuss a couple of class
 
 ## Course Resources
 
-- Course Website: <https://pdos.csail.mit.edu/6.828/2021/schedule.html>
+- Course Website: <https://pdos.csail.mit.edu/6.828/2021/schedule.html> (the Fall 2021 offering, which the Chinese translation below is based on; the latest offering is at <https://pdos.csail.mit.edu/6.1810/>)
 - Lecture Videos: <https://www.youtube.com/watch?v=L6YqHxYHa7A>, videos for each lecture can be found on the course website.
 - Translated documentation(Chinese) of Lecture videos: <https://mit-public-courses-cn-translatio.gitbook.io/mit6-s081/>
 - Text Book: <https://pdos.csail.mit.edu/6.828/2021/xv6/book-riscv-rev2.pdf>

docs/操作系统/MIT6.S081.md

@@ -1,4 +1,4 @@
-# MIT 6.S081: Operating System Engineering
+# MIT 6.1810 (原 6.S081): Operating System Engineering
 
 ## 课程简介
 
@@ -8,6 +8,8 @@
 - 课程难度：🌟🌟🌟🌟🌟
 - 预计学时：150 小时
 
+这门课自 2022 年秋季学期起，课程编号由 6.S081 变更为 6.1810，课程内容保持不变。
+
 麻省理工学院大名鼎鼎的 PDOS 实验室开设的面向MIT本科生的操作系统课程。开设这门课的教授之一 —— Robert Morris 教授曾是一位顶尖黑客，世界上第一个蠕虫病毒 Morris 就是出自他之手。
 
 这门课的前身是 MIT 著名的课程 6.828，MIT 的几位教授为了这门课曾专门开发了一个基于 x86 的教学用操作系统 JOS，被众多名校作为自己的操统课程实验。但随着 RISC-V 的横空出世，这几位教授又基于 RISC-V 开发了一个新的教学用操作系统 xv6，并开设了 MIT6.S081 这门课。由于 RISC-V 轻便易学的特点，学生不需要像此前 JOS 一样纠结于众多 x86 “特有的”为了兼容而遗留下来的复杂机制，而可以专注于操作系统层面的开发。
@@ -20,7 +22,7 @@
 
 ## 课程资源
 
-- 课程网站：<https://pdos.csail.mit.edu/6.828/2021/schedule.html>
+- 课程网站：<https://pdos.csail.mit.edu/6.828/2021/schedule.html>（2021 年秋季版本，与下方中文翻译文档对应；最新一届见 <https://pdos.csail.mit.edu/6.1810/>）
 - 课程视频：<https://www.youtube.com/watch?v=L6YqHxYHa7A>，每节课的链接详见课程网站
 - 课程视频翻译文档：<https://mit-public-courses-cn-translatio.gitbook.io/mit6-s081/>
 - 课程教材：<https://pdos.csail.mit.edu/6.828/2021/xv6/book-riscv-rev2.pdf>

mkdocs.yml

@@ -212,7 +212,7 @@ nav:
       - "ETHz: Digital Design and Computer Architecture": "体系结构/DDCA.md"
       - "ETHz: Computer Architecture": "体系结构/CA.md"
   - 操作系统:
-      - "MIT 6.S081: Operating System Engineering": "操作系统/MIT6.S081.md"
+      - "MIT 6.1810 (6.S081): Operating System Engineering": "操作系统/MIT6.S081.md"
       - "UCB CS162: Operating Systems and Systems Programming": "操作系统/CS162.md"
       - "NJU OS: Operating System Design and Implementation": "操作系统/NJUOS.md"
       - "HIT OS: Operating System": "操作系统/HITOS.md"