1. CIS 191 - Lesson 5 Lesson 5 New Skills Boot time GRUB edits (review) Changing BIOS boot order on a VM (review) Mounting CD ISO and floppy Image files on loopback devices (new) Making a diagnostics boot diskette (new)

2. Boot time GRUB edits

3. CIS 191 - Lesson 5 GRUB boot edits Fedora 9 Press any key to get boot menu

4. CIS 191 - Lesson 5 GRUB boot edits Fedora 9 Move up and down using arrow keys. Press e to edit selection.

5. CIS 191 - Lesson 5 GRUB boot edits Fedora 9 Move up and down using arrow keys. Press e to edit selection.

6. CIS 191 - Lesson 5 GRUB boot edits Fedora 9 Make changes by moving the cursor and replacing or inserting characters.

7. CIS 191 - Lesson 5 GRUB boot edits Fedora 9 For this example we replace UUID specification of the / partition with /dev/sda5, remove the rhgb and quiet options and add single to boot up in single user mode. Hit Enter when finished.

8. CIS 191 - Lesson 3 GRUB boot edits Fedora 9 Now press b to boot up using the changes

9. CIS 191 - Lesson 5 GRUB boot edits Fedora 9 The system now boots into single user mode. NOTE: The GRUB changes are temporary. /boot/grub/grub.conf must be edited to make changes permanent NOTE: The single option on the kernel line is very handy when troubleshooting boot problems.

10. BIOS boot order

11. CIS 191 - Lesson 3 BIOS Boot Order VMware BIOS 1) Click inside the VM so it has the focus 2) Tap F2 repeatedly to enter BIOS configuration. Note: You don't get much time for this so have your finger over the F2 key!

12. CIS 191 - Lesson 3 BIOS Boot Order VMware BIOS Right arrow over to the Boot menu.

13. CIS 191 - Lesson 3 BIOS Boot Order VMware BIOS Re-order to suit your needs. This VM will look first on a floppy, then a CD, then the hard drive and then try network boot.

14. CIS 191 - Lesson 3 BIOS Boot Order VMware BIOS A + means the group can be expanded (use Enter) Noter: VMware BIOS does not support USB pen drive boots.

15. CIS 191 - Lesson 3 BIOS Boot Order VMware BIOS If you have multiple hard drives, they can be searched in order as well

16. CIS 191 - Lesson 3 BIOS Boot Order VMware BIOS Save any changes you make.

17. loopback mounts

18. CIS 191 - Lesson 5 Lesson 5 Mounting CD ISO and floppy Image files on loopback devices Desired: Be able to directly mount an CD ISO image file. Avoids having to burn downloaded ISO's on to CD's, then loading the new CD into computer, and then finally mounting /dev/cd0. Solution: Use loopback devices.

19. /boot /dev / /bin/etc/mnt cdrom/ /dev/boot/home cis191/ grub/ lost+found/ floppy/ /lib /dev/sdb1 /dev/sda1 /dev/sda5 Mounting File Systems Like pinning the tail on the donkey mount /dev/sdb1 /mnt /lib /bin CIS 191 - Lesson 5

20. / /bin/etc/mnt bin/ /dev/boot/home cis191/ grub/ lost+found/ boot/ dev/ /lib /dev/sda1 /dev/sda5 Mounting File Systems Like pinning the tail on the donkey /dev/sda6 mount /dev/sdb1 /mnt lib/ CIS 191 - Lesson 5

21. / /bin/etc/mnt cdrom/ /dev/boot/home cis191/ grub/ lost+found/ floppy/ /lib /dev/sda1 /dev/sda5 Mounting Image Files Like pinning the tail on the donkey mount –o loop Desktop/rescue-cd.iso /mnt rescue-cd.iso CIS 191 - Lesson 5

22. / /bin/etc/mnt /images /dev/boot/home /rsimms /grub /lost+found /isolinux TRANS.TBL /lib /dev/sda1 /dev/sda5 Mounting Image Files Like pinning the tail on the donkey /dev/loop0 mount –o loop Desktop/rescue-cd.iso /mnt CIS 191 - Lesson 5

23. HW Diags

24. CIS 191 - Lesson 5 Diagnostics boot diskette Checking out your system prior to installing Linux Check RAM quantity Check drive sizes Inspect other hardware resources as necessary

25. CIS 191 - Lesson 5 Diagnostics boot disk BIOS code Floppy with boot code for DOS Boot order with floppy drive at top When DOS loads, autoexec.bat run diagnostics program

26. CIS 191 - Lesson 5 Diagnostics DIAG, the diagnostic program

27. CIS 191 - Lesson 5 Installation RAM Requirements & Configuration Issues The more RAM the better Graphics (X Windows) runs best with a minimum of 64MB RAM Swap space size should be 1.5 to 2 times RAM – up to 256 MB. At 256MB RAM and above, swap space should equal RAM

28. CIS 191 - Lesson 5 Trouble shooting

29. CIS 191 - Lesson 5 Booting the System 1.Power On Self Test (POST) – loads the BIOS. 2.BIOS loads the Master Boot Record. 3.MBR read its partition table to determine which partition to boot into. 4.MBR loads the boot program in the active partition. 5.Boot program presents user with boot prompt menu. 6.Based upon user selection, boot program loads desired kernel along with and supplied boot options 7.Kernel uncompresses and loads into memory. 8.Kernel detects hardware and initializes its data. fdisk boot order grub.conf

30. CIS 191 - Lesson 5 Rooting the System 1.Kernel mounts the root file system 2.Kernel creates and starts the init process 3. init reads /etc/inittab for its instructions 4. init performs system initialization: presents some kind of welcome banner allows for and interactive startup set up keyboard mapping, system fonts, plug and play devices, … checks for dirty file systems, can clean them if necessary checks disk quotas and swap space mounts all file systems 5.Chooses which runlevel to come up in and executes those scripts via rc script 6.daemons load 7.getty processes are spawned on terminal devices /etc/inittab grub.conf /etc/rc.d

31. CIS 191 - Lesson 5 Preparing for trouble Record your partition and mount information (output from fdisk –l and mount ) Make a copy of your MBR. For example: dd if=/dev/sda of=mbr bs=512 count=1 Create a bootable rescue floppy with GRUB installed that roots to your / partition on your Linux system. Record grub.conf Record MBR xxd output Record /etc/inittab

32. CIS 191 - Lesson 5 Rescue boot devices Put pristine GRUB stage1 and stage2 files Add GRUB config files for more control Add a kernel for more options Make vender rescue disk Add a kernel and small root file system with tools Use small Linux distribution like Knoppix

33. CIS 191 - Lesson 5 Making rescue floppy RH9 example Boot Sector /dev/fd0 Method I The "simplest rescue diskette" cd /usr/share/grub/i386-redhat cat stage1 stage2 > /dev/fd0 Note: this will allow you to boot directly into GRUB. At boot time you would manually enter (use tab completes!): grub grub> root (hd0,0) grub> kernel /vmlinuz-2.4.20-6 ro root=/dev/sda2 grub> initrd /initrd-2.4.20-6.img grub> boot Method II grub grub> root (hd0,0) grub> setup (fd0) grub> quit Boot Sector /boot MBR Boot Sector / swap /dev/sda2 /dev/sda3 /dev/sda1

34. CIS 191 - Lesson 5 Making rescue floppy Installing boot code into floppy boot sector Boot Sector /dev/fd0 Method III (RH9) mkbootdisk --device /dev/fd0 $(uname –r) Method IV Put grub files to floppy and setup boot sector to use them. See Howto on "Trouble" Boot Sector /boot MBR Boot Sector / swap /dev/sda2 /dev/sda3 /dev/sda1

35. CIS 191 - Lesson 5 The faces of trouble

36. CIS 191 - Lesson 5 The faces of trouble

37. CIS 191 - Lesson 5 The faces of trouble

38. CIS 191 - Lesson 5 The faces of trouble

39. CIS 191 - Lesson 5 The faces of trouble

40. CIS 191 - Lesson 5 The faces of trouble

41. CIS 191 - Lesson 5 The faces of trouble

42. CIS 191 - Lesson 5 The faces of trouble

43. CIS 191 - Lesson 5 The faces of trouble

44. CIS 191 - Lesson 5 The faces of trouble

45. CIS 191 - Lesson 5 The faces of trouble

46. CIS 191 - Lesson 5 The faces of trouble

47. CIS 191 - Lesson 5 The faces of trouble

48. CIS 191 - Lesson 5 The faces of trouble

49. CIS 191 - Lesson 5 For the command/file collection TaskCommand or file The simplest boot floppy. cd /usr/share/grub/i386-redhat/ cat stage1 stage2 > /dev/fd0 After booting into grub, manually enter appropriate grub commands you would normally see in grub.cong Make RH9 emergency boot disk mkbootdisk --device /dev/fd0 $(uname –r) Mount CD ISO or floppy disk images on loopbacks mount –o loop Desktop/rescue-cd.iso /mnt mount –o loop Desktop/rescue-floppy.img /mnt Backup MBR to file named mbr dd if=/dev/sda of=mbr bs=512 count=1 Make rescue floppy for specific system grub > root (hd0,0) (location of /boot) > setup (fd0) > quit