Lecture #5 Storage Devices and Filesystems

Agenda

1. Log on to CISVLAB and boot up your CentOS system stopping it at the GRUB menu screen.
   • Compare the menu screen with the grub.conf configuration file.
   • How would you boot into your minimal filesystem on /dev/sda3?
   • What is the initrd.img file for?
2. Log on to your CentOS system:
   • Create an initial ramdisk for your minimal file system
   • How do you make an initial ramdisk?
3. VTEA Surveys
4. Break
5. Configure /etc/fstab so that the /boot filesystem does not mount at boot time.
   Reboot your system and look at the /boot directory. What do you observe?
6. Manually mount the device containing the kernel to the /boot directory:
   mount /dev/sda? /boot
7. Filesystem Handouts.
8. Create a second scsi 4 GB hard disk for the CentOS system, use thin provisioning.
   • Create an ext3 filesystem on it.
   • Mount it to the /home directory on the root filesystem.

Assignment

• Read the first 7 sections of Chapter 12.
• Do Lab 4
• Extra Credit
  

Resources

• PowerPoint Slides
• Disk storage and file system handout
• Lecture 4 Archive

Questions

1. Where do file systems reside?
2. What is a mount point?
3. What is a mounted file system?
4. Why would an attempt to unmount a file system fail?
5. What is the /etc/fstab file used for?
6. Describe the difference between the mkfs command and the fdformat command.
7. Explain the relationship between file systems and the file directory hierarchy.

Files and File Systems

1. Disk Partitions
   • Master Boot Record
     1. Boot Loader: up to 446 bytes of machine code that reads the following partition table.
     2. Partition Table: 64 bytes that hold the type, size and location of the four primary partitions.
     3. Two-byte Signature: 0x55aa
   • Partitions
     1. Primary - up to 4
     2. Extended - maximum of 1
            May contain arbitrary number of logical partitions.
   • Exercise: Use the rest of your disk to create an Extended partition, and within that partition, create a 32MB Linux partition.
2. File systems: Raw vs. Structured data
   1. Superblock
   2. Inode Table (List)
   3. Data blocks
   4. lost+found directory
   5. File Systems are create with: mkfs -t type Device [size]
   6. Exercise: Create a filesystem in the partition you created above (/dev/hda5).
   7. Mounting and Unmounting File Systems
      • mount [device-file] [directory]
      • umount [device-file | directory]
      • Mount information
        1. /etc/fstab
        2. /etc/mtab
3. File Types
   1. Ordinary files
   2. Directories
   3. Symbolic (soft) links
   4. Special files: device files

Relevant Commands and Files