CIS 225

Lecture 10: Operating System Troubleshooting

Windows Troubleshooting

• Safe Mode
• Boot from Repair CD
• Blue Screen Errors
• System Restore
• Task Manager
• Startup Processes
• Password Reset

List Source: Lifehacker

VMWare Boot Delay

To change boot options in VMWare:

• Open the .vmx file in a Text Editor
• Add the following to the file
  

  bios.bootdelay = 10000

• Save the file
• Press ESC at loading screen to open boot menu

Safe Mode

Used to troubleshoot problems preventing Windows from starting normally

• Windows 95 - Windows 7: Press F8 before Windows loading screen
• Windows 8: Hold SHIFT while clicking Restart
• Guide from How-To Geek

Boot from Repair CD

Helps fix problems stopping Windows from booting at all

• Insert the Installation CD
• Choose "Repair my Computer"
• Guide from How-To Geek

Blue Screen Errors

Usually driver or system file related issues

• Check Error Code online
• Check Windows Error Logs
• Verify System Files
• Use System Restore
• Advanced: Analyze minidump files

Windows Error Logs

Stores important information about events on Windows

• Go to Control Panel and search for "Log"
• Click "View Event Logs"
• Click "Windows Logs" on the left
• Click "System" on the left

System File Check

Ensure system files haven't been corrupted

• Open a Command Prompt as Administrator
• Run the following command
  

  sfc /scannow

• Wait for the results

System Restore

Restore core system files from a backup

• Open Control Panel and search for "Recovery"
• Choose the "Recovery" option, then choose "Open System Restore"
• Choose a time before the error, then choose to restore

Analyze Minidump

• Minidump files store information about the system state when a crash occurs
• Programs can analyze the data to see what caused the crash
• Good last resort

Task Manager

• See which processses are using resources
• Find and stop processes causing slowness or issues

Also recommend using Process Explorer from Sysinternals

http://live.sysinternals.com

Startup Processes

• Look at processes that run at boot time
• Easily remove unneeded processes

Recommend using Autoruns from Sysinternals

http://live.sysinternals.com

Reset Passwords

• Passwords stored in the Windows Registry as a hashed value
• Can easily replace passwords with known hash
• Only defense is physical security or encryption

Recommend using Offline NT Password & Registry Editor from Peter Nordahl

Ubuntu Troubleshooting

• Single User Mode
• Boot from Repair CD
• System Logs
• Process Management
• Startup Processes
• Password Reset

List Source: Lifehacker

Single-User Mode

Allows you to operate the system as the root user

• Hold SHIFT while Ubuntu is booting
• Choose "Advanced Options for Ubuntu"
• Choose a kernel with "(recovery mode)" at the end
• After some text, choose the "root" option

Recovery CD

• The installation CD also boots to a full Ubuntu system
• Can use the same troubleshooting tools you would have on a working system
• Can even install software!

System Logs

• Store information about system events
• Stored in /var/log directory
• Important logs:
  • auth.log - user logons
  • dmesg - driver messages
  • dpkg.log - software installation
  • kern.log - kernel messages
  • syslog - system messages

Processes

• ps -A - view ALL system processes
• top - view top processes
• pstree - view process tree
• kill <pid> - stop a process by pid
• Force a process to stop
  

  sudo kill -9 <pid>

• pkill <command> - kill process by name

Startup Processes

• Click Applications and find Startup Applications
• You can manage some applications here
• To show ALL applications, see this site
• For other services, it's complicated

Ubuntu Password Reset

• Start in Single User Mode
• Get to a root console
• Use the following commands:
  

  mount -o rw,remount /
  passwd <username>

• Can't remember your username:
  

  ls /home

Reading

• Windows 8 Book - Chapter 7
• Ubuntu Unleashed - Chapter 11

Assignments

• Lab 4 - Scripting 2: Due 9/30 @ 11:59 PM
• Exam 1 - Wednesday 10/2 during class

Exam Prep

• 24 Multiple Choice
• 6 Short Answer
• 1 handwritten note sheet allowed
  • No larger than 8.5" x 11"
• Material from
  • Lecture Slides
  • Lab Assignments
  • Class Discussion