1. Day 1 Tasks How do you backup the MBR (Master Boot Record) of a hard disk? How do you backup the primary partition table of an MBR type hard disk? How do you restore the partition table of an MBR type hard disk? What is the maximum number of partitions you can create on a SATA hard disk? How do you configure a hard disk to dual boot between Windows and Linux? How do you reset a forgotten root password on a Linux system? SRT210 Summer 2014 – May 6, 2014

2. 1. How do you backup the MBR (Master Boot Record) Of a hard disk?

3. 1. How do you backup the MBR (Master Boot Record) Of a hard disk? MBR: the 1 st 512 bytes of a hard disk Given: hard disk device name=/dev/sda Backup to file: /root/mbr.dd Answer: By using the following “dd” command dd if=/dev/sda of=/root/mbr.dd bs=512 count=1 or dd if=/dev/sda of=/root/mbr.dd count=1 or dd if=/dev/sda of=/root/mbr.dd count=1 2>/dev/null

4. 2. How do you backup The primary partition table Of an MRB type hard disk?

5. 2. How do you backup The primary partition table Of an MRB type hard disk? Partition table on MBR: 64 bytes starting at bytes 447 on MBR (note: counting from zero) Given: hard disk device name=/dev/sda Backup to file: /root/ppt.dd Answer: By using the following “dd” command dd if=/dev/sda of=/root/ppt.dd skip=446 bs=1 count=64

6. 3. How do you restore The primary partition table Of an MRB type hard disk?

7. 3. How do you restore The primary partition table Of an MRB type hard disk? Partition table on MBR: 64 bytes starting at bytes 447 on MBR (note: counting from zero) Given: hard disk device name=/dev/sda MBR file that contains a good ppt: /root/mbr.dd Warning: the following command may destroy ALL the data on your hard disk, use at your own risk. Answer: By using the following “dd” command dd of=/dev/sda if=/root/ppt.dd seek=446 bs=1 count=64 (note: check out the use of ibs and obs flags in dd man page)

8. 4. What is the maximum number Of partition you can create On a SATA hard disk?

9. 4. What is the maximum number Of partition you can create On a SATA hard disk? ● At least 4 on all platform. ● At least 16 on Linux ● Actual maximum value depends on driver implementation

10. 5. How do you configure a hard disk To dual boot between Linux and Windows?

11. 5. How do you configure a hard disk To dual boot between Linux and Windows? ● Two options: ● Using Windows boot loader – need to copy Linux boot codes to Windows partition ● Using Linux boot loader (GRUB) – only need to configure GRUB's configure file

12. 5. How do you configure a hard disk To dual boot between Linux and Windows? ● Using Linux boot loader (GRUB): ● Need GRUB MBR on the hard disk ● Need the correct PPT on MBR ● The ppt must contains the partition information for Linux and Windows ● Need to add a Windows entry to GRUB's configure file

13. 5. How do you configure a hard disk To dual boot between Linux and Windows? ● GRUB Configure file for dual boot: See Unix and Linux System Administration Handbook 4 th Edition Page 83-85 title Windows Server 2008 rootnoverify (hd0,2) chainloader +1 Note: (hd0,2) --> first hard disk, 3 rd partition

14. 6. How do you reset a forgotten root password On a Linux System?

15. 6. How do you reset a forgotten root password On a Linux System? ● At least there are two options: ● 1. Boot to single user mode ● Most Linux system does not ask for super user password to become root – security risk! ● Once in single user mode (run as root), you can reset the root password. ● 2. Boot with a Linux Live CD/DVD ● Once Linux is up and running, mount the root partition and manually change the password filed in the shadow file.