EE512 System Programming Prologue

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EE512 System ProgrammingPrologue Project1
T.A Youngwoo Park Computer Engineering Research
Laboratory Korea Advanced Institute Science
Technology Sep 10, 2008
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Project Schedule

• OS System calls
• Process and Threads
• Scheduling
• Synchronization
• Deadlocks
• Basic Memory Management
• Paging
• Page Replacement
• Segmentation
• File System
• I/O

Project 1
Project 2
Project 3
Project 4
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Overview of Projects

• Topics covered
• Project 1 Shell Scheduling
• Project 2 Synchronization
• Project 3 File System
• Project 4 Porting to H/W or Memory Management
• Policies
• There will be 4 to 5 design and programming
  assignments.
• Each project must be done individually.

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Project 1 - 3
App.
Minix 3.1.2
Minix Image
Kernel
Windows 200 / XP / Vista
Hardware Platform
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Project 4
App.
Minix 3.1.2
Kernel
Hardware Platform
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Setting up Minix for Projects

• Goal
• to install a Minix you can use in future projects
  
• to familiarize yourself with the system
• to build and (slightly) modify the Minix kernel
• S/W Requirement
• Minix Image
• (http//www.minix3.org/download/).
• Vmware Server
• (http//www.vmware.com/download/server/).

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Setting up Minix for Projects

• Minix Image Vmware Server

(http//www.minix3.org/download/).
(http//www.vmware.com/download/server/)
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Creating Virtual Machine
Select "Local host"
New Virtual Machine
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Creating Virtual Machine
Virtual Machine Setting (Typical)
Virtual Machine Setting (Other)
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Creating Virtual Machine
Virtual Machine Setting (Name)
Virtual Machine Setting (Network) Change the
Ethernet setting from Bridged .. to NAT
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Creating Virtual Machine
partitioning the hard drive
VM is generated!!
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Install Minix
booting Minix from the downloaded image
Power-On the created Virtual Machine
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Install Minix
Log in as root
Run the setup script
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Setting Minix
? Keyboard type us-std ? Ethernet card 6 (AMD
LANCE) ? Full Install ? Automatic mode (Enter) ?
Disk Number 0 ? Region Number 0 ? Confirm yes ?
Size of Home 804 ? Block Size 4 KB

• "shutdown" and boot d0p0

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Configure the System
Install Utils
"packman" and select "2" Binary packages
sources from CD
Installing
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Minix usage

• Editing in Minix
• Using vim editor
• Type vim filename
• i means insert
• You will edit files after type i
• After editing files,
• push esc button wq
• wq means save quit
• q means quit
• q! means compulsory quit
• You can easily find commands of vi in google or
  naver
• Edit in your PC and download file
• But it is inconvenient to debug code

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How to modify and rebuild the kernel

• cp -r /usr/src /usr/src.clean
• Source Backup
• Using Make
• Reboot Customized Kernel

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How to modify and rebuild the kernel

• Rebuild the kernel
• Switch to the directory /usr/src/tools
• Invoke make
• Check the options to see how a kernel can be
  rebuild and installed
• Restart Minix Select the third option Start
  custom kernel

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How to copy source codes (1)

• In Windows PC
• Execute ftp program (ex ALFTP)

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How to copy source codes (2)

• In Minix
• Type ftp ip address
• Username
• Password
• Type put filename

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How to solve network problem

• If no problem
• Setting Network IP ifconfig h ipaddress
• Ex) ifconfig h 143.248.165.202

• If having problem
• Change the Ethernet setting from Bridged .. to
  NAT
• Reference site http//www.minixtips.com/2006/06/
  minix-with-static-ip-address.html

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• Project 1

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Project Overview

• Project Goal
• To understand important system calls and
  integrate them into a shell
• To understand the Minix kernel structure and
  play around with the scheduling code
• Source Code

Task 2 RT Scheduler
Task 1 Shell
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TASK? Implement a basic shell (1)

• Shell A command line interpreter that accept
  input from the user and executes the command that
  are given
• ex) bash, tcsh, ksh, csh,

• Assignments
• shell when shell is ready to accept commands
• Execute commands
• ex) ps, ls, cat,

• Redirect the standard input or standard output
• Change the direction of standard input output
  using lt, gt
• ex1) ls l gt aa.txt (Dont display result of ls
  l but store it in aa.txt)
• ex2) sort lt aa.txt (Display contents of aa.txt
  by sorting)

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TASK? Implement a basic shell (2)

• Assignments contd
• Pipe the output of commands to other commands
• Connect two processes using
• Example
• ps sort gt sort.txt ( ps gt ps.txt, sort
  psout.txt gt sort.txt)
• Put commands in the background using
• Implement exit command
• exit command quit the shell
• Shell should be called recursively
• Submission
• Submit my_shell.c
• If implementing shell in various codes, submit
  my_shell.tar

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TASK I Implement a basic shell

• Flow of a basic shell
• while(1)
• fgets() to get inputs
• Parsing inputs to get what command is
• pid fork()
• if(pid -1) error
• else if (pid 0) child process
• execvp() execute command
• else parent process
• waitpid() wait a child process

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TASK I Implement a basic shell

• Implement pipe, redirection, and background
• Redirection
• open(), read(), write() system call related with
  file
• dup() systemcall
• Pipe
• pipe() systemcall
• Background
• Dont wait child process which is executed in
  background
• Handle the process when it is finished

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? Scheduler for a real-time process (1)
2. Tasks

• Assignments
• Allows a user process to temporarily become a
  real-time process and scheduled by its own
  priority
• When running as a real-time process, the process
  should always be scheduled before any other user
  processes
• However, To have all the system processes (such
  as kernel, server, and device drivers) to take
  precedence over a user task

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? Scheduler for a real-time process (2)

• Real-time scheduling
• To enter this mode, invoke the new system call
  enter_rt
• Limit the time to run in real-time mode
• If this time has expired, the process
  automatically is back into normal mode
• Only allow a single process to run in real-time
  mode
• Priority scheduling
• To decide priority, invoke the new system call
  set_priority(int priority)
• The priority of user process is decreased when
  the process is scheduled
• The real-time user process has the highest
  priority
• Submission
• Submit Sched.patch
• contains the patch to the Minix kernel to
  implement the scheduler

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TASK II Scheduler for a real-time process

• Add a new system call, enter_rt(clock_t period)
• Refer the material How to Add a New System Call
  for Minix 3
• Example add printmessage() system call
• Flow of using a system call

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TASK II Scheduler for a real-time process

• Creating a system-call handler
• /usr/src/servers/pm/table.c
• /usr/src/servers/pm/proto.h
• /usr/src/servers/pm/misc.c
• Compiling the PM server
• Calling the system-call handler function directly
• /usr/src/lib/syslib/sys_enter_rt.c
• /usr/src/include/minix/com.h /usr/include/minix/
  com.h
• /usr/src/include/minix/syslib.h
  /usr/include/minix/syslib.h

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TASK II Scheduler for a real-time process

• Creating a User Library Function
• Map the system-call number of the handler
  function
• /usr/src/include/minix/callnr.h
• /usr/include/minix/callnr.h
• Define the prototype function in header file
• /usr/src/include/unistd.h
• Implement library function
• /usr/src/lib/posix
• Implement system call handler
• /usr/src/kernel/system/do_enter_rt.c
• /usr/src/kernel/system.h
• /usr/src/kernel/system.c

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TASK II Scheduler for a real-time process

• Process scheduling
• /usr/src/kernel/proc.c
• pick_proc() Decide who to run now
• sched() Determine the scheduling policy
• /usr/src/kernel/proc.h
• /usr/src/kernel/glo.h
• /usr/src/kernel/clock.c
• Determine when the real-time period of the
  process has expired and need to be put back into
  normal mode

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Evaluation Criteria
3. Evaluation Criteria

• Project report
• Test cases, codes
• Code Organization
• Code Readability
• Comments
• No errors no warning
• Assignment 1 30
• Assignment 2
• Real-time scheduling 40
• Priority scheduling 20

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Submit
4. Submit

• Due date September 24th (Tue), 2359
• Collect all modified code and tar
• tar cvf directory
• You should explain how to execute your new
  application and kernel and test your submission
• For code, follow the submission method in handout
• (!) Your own test code policy should be
  included
• With project report (studentnumber.doc or .hwp)
• Studentnumber.zip
• To ywpark_at_core.kaist.ac.kr
• Title EE512-Project1 Studentnumber
• Ex) EE512-Project1 200731xx
• Penalty
• If copied, no points
• Delay 10/day (received time of e-mail)

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Reference

• How to add a new system call for Minix3

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Question