--- a/slide.md	Fri Jun 21 15:28:51 2019 +0900
+++ b/slide.md	Sat Jun 22 12:32:52 2019 +0900
@@ -1,39 +1,127 @@
-title: Studying Operating System Using Docker  
+title: Studying Operating System Using Docker Platform  
 author: Shivani Dubey
-profile: Intern, University of the Ryukyus 
+profile: Madan Mohan Malaviiya, University of Technology
+
+## Why we study Operating System?
+
+- Every computer system has an operating system, which manages the resource of the computer.
+
+- IoT or IT Services can't work well without resource manageents.
+
+- To handle it, we have to understand the API of OS
+
+- To understand the API, it it better to see the implentations.
+
+- For an example, API for tuning priorities of the processess
+
+## Xv6 Operating System as an educational tool
+
+- A Unix-like operating system developed in MIT, based on V6 kernel.
+
+- xv6 is written in ANSI C ( not in C++ ).
+
+- xv6 is small and simple (9628 lines of codes)
+
+- It can run on Respberry Pi ( Small PC board )
+
+- Or on ARM emulator such as QEMU
 
-# Introduction
+## Xv6 development envrionment with QEMU
+
+- QEMU emulates ARM CPU with virtual memory 
+
+- Xv6 operating sytem itself is running on QEMU 
+
+- gdb debugger can be attached to the emulated program (both in user space and system space)
+
+- We can step and trace the internal of xv6 kernel
+
+      ... but it requires complex development envrionments setup
+      ... very time consuming
+
+## Our development envrionments 
+
+- emacs editor (amidst the editor war between vi and emacs!)
+
+- homebrew (it simplifies installation of software in macOS)
+
+- Mercurial repository of the lab where we saved everything using ssh 
+
+- Cross Compilers 
+
+- ARM libraries for C language
+
+- QEMU (ARM Emulator)
 
+## Introducing Docker
 
-- Docker
-- xv6
+- What is Docker? It is a container.
+
+- What is Container? An isolateed envriornment such as file system.
+
+- It has DockerFile, which describes how to setup the envrionment in the container
+
+- Docker can run on any computer using an emulator such as QEMU
+
+- Complex develement environment can be build using DockerFile and docker built command.
+
+# The DockerFile
+
+```
+FROM phitek/qemu-arm
+RUN apt-get update -y
+RUN apt-get remove gdb -y
+RUN apt-get install gcc-arm-none-eabi gdb-arm-none-eabi qemu-system-arm -y
+WORKDIR /code
+COPY ["src", "."]
+RUN make
+CMD /bin/bash
+```
+
+- FROM lines specifies the shared image in Docker repository.
+
+- apt-get install Linux cross compiling tools
 
-Why Docker?
+- then it create workig directory, and copy our sources to it, and execute make
+
+## Docker command
+
+- create docker imagae and environment, and built xv6 kernel
+
+  docker build --tag xv6-docker .
+
+- run xv6 kernel on QEMU in the container
+
+  docker run --rm --privileged -it xv6-docker ./run-debug.sh
+
+- run gdb to connect the xv6 kernel running in the QEMU
+
+  docker exec -it xv6-docker ./debug.sh
+
+## Features of Docker:
+
+- Easy and Faster Configuration
+
+- Increases productivity
+
+- Application Isolation
+
+- Provies Services
+
+- Security Management
 
 
-The modern platform for high velocity innovation.
-Docker container is not any specific platform. It can run on any computer, on any infrastructure and in any cloud.
+# Exercise : adding priorities to the xv6 scheduler 
 
-## Features of Docker 
+- Added getpriority() and setpriority() 
+
+- get_highest_priority() functions in proc.c file of xv6
 
-- Easy and Faster Configuration
-- Increases productivity
-- Application Isolation
-- Swarm
-- Routing Mesh
-- Services
-- Security Management
+- implement it in schelduler()
 
-What is xv6?
-
-
-xv6 is modern reimplementation of Sixth Edition Unix in ANSI C.
+- Added a test function testpriority() in usertests.c file of xv6 to implement our algorithm
 
-## Scheduling processes by their priorities
-
-
-
-We implemented the concept of scheduling processes by their priorities. 
+##  The function 
 
 ```c
 int get_highest_priority_proc(void)
@@ -59,9 +147,34 @@
 }
 ```
 
+- It assumes at least one process is RUNNABLE
 
-## Docker Limitations
+- It may allow no highest priority process.
+
+- The correctness of the function is *important*.
+
+## Docker Limitation
+
+- If repository breaks, Docker poses a problem (a cloud probelm)
+
+- Clound should be used conviniently but don't rely on it.
+
+- We can use a direct environment without Docker, since we have a Linux server.
+
+- Docker images can easily eats up our disk spaces.
 
-
+in ~/.zsh_history
 
-Docker environment poses some problems, some of which are difficult to comprehend.
\ No newline at end of file
+```c
+: 1561014922:0;docker system prune
+: 1561014973:0;docker container prune
+: 1561015350:0;docker image prune
+: 1561015362:0;docker volume prune
+```
+# Conclusion
+
+- Docker environment poses some problems, some of which are difficult to comprehend 
+
+- Storage is difficult too
+
+- Yet, it gives a good insight of the underlying important concepts of operating system beacuse it is well documented, fast and uses less resources