Week Fourteen Student name: David LongOpen source topic : KeePassStudent name: Matthew TankersleyOpen source topic : Blender 3D ModelingStudent name: Mark CloningerOpen source topic : Computer Aided DesignStudent name: Pattie Buffenbarger• Open source topic : ScrapyStudent name: Bill Knox• Open source topic : Freeplane

UNIX Operating SystemThe dumpe2fs command prints the super

block and blocks group information for the filesystem present on a device. Lab Assignment 12-1 can be submitted using the dumpe2fs command. The dumpe2fs command must be used on Knoppix software because the Unix / Linux filesystem blocks.

UNIX Operating SystemBlocks are used for two different purposes:

Most blocks store user data aka files (user data).Some blocks in every file system store the file system's metadata. So what is

metadata?In simple words Metadata describes the

structure of the file system. Most common metadata structure the superblock, inode and directories.

UNIX Operating SystemSuperblock:

Each file system is different and they have a type like ext2, ext3, and ext4 etc. Further each file system has size like 5 GB, 10 GB and status such as mount status. In short each file system has a superblock, which contains information about file system such as:

1. File system type2. Size3. Status4. Information about other metadata

structures

UNIX Operating SystemIf the super-block is lost or damaged, you

are in trouble (data loss) so Linux maintains multiple redundant copies of the superblock in every file system. This is very important in many emergency situations, for example you can use backup copies to restore damaged primary super block. Following command displays primary and backup superblock location on /dev/sda3:# dumpe2fs /dev/hda3 | grep -i superblock

UNIX Operating SystemThe primary superblock is resides on block group 0,The back up superblock is resides on block groups 1, 3, 5, 7, 9.

UNIX-like Operating System

The cs.franklin.edu machine requires root permission to execute the dumpe2fs command.tune2fs command is helpful to manipulate the filesystem parameters of a ext2, or ext3, or ext4 type file system.

UNIX-like Operating SystemWhat is a shared library?

Shared libraries are libraries that are loaded by programs when they start. When a shared library is installed properly, all programs that start afterwards automatically use the new shared library.

UNIX-like Operating SystemShared libraries are much more flexible and sophisticated than mentioned in the previous slide, because the approach used by Linux permits you to:

• Update libraries and still support programs that want to use older, non-backward-compatible versions of those libraries;

• Override specific libraries or even specific functions in a library when executing a particular program.

• Do all this while programs are running using existing libraries.

UNIX-like Operating SystemRecognizing shared library namesEvery shared library has a special name called the ``soname''. The soname has the prefix ``lib'', the name of the library. One important libraries is the C library (libc). Another common type library is the one associated with GUIs. These libraries are often referred to as widget sets, because they provide the on-screen widgets used by programs – buttons, scroll bars, and menu bars.

UNIX-like Operating SystemShared libraries are stored somewhere in the filesystem. The GNU standards recommend installing by default all libraries in /usr/local/lib when distributing source code (and all commands should go into /usr/local/bin).

UNIX-like Operating SystemLocating shared library filesTo Set the library path is to edit the /etc/ld.so.conf file. This file consists of a series of lines, each of which lists one directory in which shared library files may be found./etc>cat ld.so.confinclude ld.so.conf.d/*.conf

UNIX Operating System

All lab assignments due by December 20, 2014.

Lab Assistance available by phone and/or email