ITEC400 Winter 2017 Week Fourteen Professor Robert D’Andrea

Agenda 1. Present weekly Power Point presentation 2. Open source presentations 3. All lab assignments due by April 15, 2017.

Week Fourteen Presenters Student name: Kenneth Doughman Topic: KODI Student name:  William Brandon Topic: FreeNAS Student name: Michael Turley Topic: Wireshark Student name: Rachel  Riouse Topic: Open Office Student name: John Van Kirk Topic: SugarCRM Student name: Steven Hunt Topic: Xampp Student name: Matthew House Topic: Django

Week Fourteen Presenters Student name: Laura Cummins Topic: process hacker Student name: Julie Stewart Topic: Mozilla Firefox web browser Student name: Kylee Williams Topic: Webmin Student name: Brandon Heddleson Topic: CodeCombat Student name: Fernando  Arreguin Topic: Clonezilla  

UNIX Operating System The dumpe2fs command prints the super block and blocks group information for the file system 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 file system blocks.

UNIX Operating System Blocks 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 System Superblock: 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 type 2. Size 3. Status 4. Information about other metadata structures

UNIX Operating System If 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 System The primary superblock resides on block group 0, and 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 file system parameters of a ext2fs, or ext3fs, or ext4fs type file system.

UNIX-like Operating System What 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 System Shared 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 System Recognizing shared library names Every 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 System Shared libraries are stored somewhere in the file system. 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 System Locating shared library files To 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.conf include ld.so.conf.d/*.conf

UNIX-like Operating System

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