Linux Kernel ,ISO images

-
Q.What is Kernel? Explain the task it performs. 

Ans: Kernel is used in UNIX like systems and is considered to be the heart of the operating system. It is responsible for communication between hardware and software components. It is primarily used for managing the systems resources as well.
Kernel Activities:
The Kernel task manager allows tasks to run concurrently.
Managing the computer resources: Kernel allows the other programs to run and use the resources.Resources include i/o devices, CPU, memory. Kernel is responsible for Process management. It allows multiple processes to run simultaneously allowing user to multitask. Kernel has an access to the systems memory and allows the processes to access the memory when required. Processes may also need to access the devices attached to the system. Kernel assists the processes in doing so.For the processes to access and make use of these services, system calls are used.

Q. Different types of Kernel.

Ans .Monolithic Vs Modular Kernel
Monolithic kernel is one single program that contains all of the code necessary to perform every kernel related task.  Most UNIX and BSD kernels are monolithic by default.
    Some advantages hinge on these points:
    Since there is less software involved it is faster. As it is one single piece of software it should be smaller both in source and compiled forms.
Less code generally means less bugs which can translate to fewer security problems.

Modular kernel allows an administrator to add functionality only when required. Keeping only what's necessary in kernel memory reduces the kernel's memory footprint and increases its overall performance. A few advantages to the modular kernel are: Faster development time for drivers that can operate from within modules. No reboot required for testing (provided the kernel is not destabilized). On demand capability versus spending time recompiling a whole kernel for things like new drivers or subsystems. Faster integration of third party technology (related to development but pertinent unto itself nonetheless).


Q.What is Initial Ram disk?

Ans: An initial ram disk is a temporary file system used in the boot process of the Linux kernel. initrd and initramfs refer to slightly different schemes for loading this file system into memory. Both are commonly used to make preparations before the real root file system can be mounted.

Q. Explain Different Option for updating kernel?

Ans:
A. install new kernel from rmp file
a. Get the Newest kernel and put in /tmp
b. rpm -i  /tmp/kernal-2.4.19-3.i386.rpm (Not ugrading.can be switched to old keranl if need)
c. Now Kernal ,RamDisk etc..are installed in /boot
d. New stanza added to grub.com (you need alter "default")

B. customizes, install and configure from kernel source code.
Required RMP's tool for customizing kernel source code.
             1. Kernel-source-*
             2.glibc-kernheaders-*
             3.glibc-deve;-*
             4.cpp-*
             5.binutils-*
             6.gcc-*
             7.tcl-*
             8.tk-*

Q. Explain the Steps to compile and install kernel?

Ans:    make mrproper  -- clean up the directory tree
            make xconfig -- tools for customixing the kernal
            make dep --- makes and build the dependecies
            make clean --- cleans any unecessary files used to build the previous steps
            make bzimage -- actually builds the kernel
            make modules -- Builds the modules
            make modules_install -- Install kernel modules
            make install -- copy the new kernel files to associated directory.


Q.What are ISO image files?



Ans: An ISO image is an archive file (also known as a disk image) of an optical disc in a format defined by the International Organization for Standardization (ISO). ISO image files typically have a file extension of .iso. The name ISO is taken from the ISO 9660 file system used with CD-ROM media according towikipedia.org.



Q. How to create an ISO image?



Ans: As of now I know two methods to create an ISO file. One is through dd command (disk dump) and other is mkisofs command



Q. Creating ISO files from cd-rom/dvd by using dd command



Ans: #dd if=/dev/cdrom of=/temp/songs.iso

dd if=/dev/dvd of=/temp/songs1.iso # for dvd

dd if=/dev/scd0 of=/temp/songs2.iso # if cdrom is scsi



Let me explain what actually the above command will do. dd is a disk dump command which will present in most of the Linux/nix systems and "if"specifies input file and "of" specifies output file. So we are specifying to dd command what is our input file and where is our output file.



Q. Creating ISO file using mkisofs command.



Ans: Method1: Creating an iso image from cd-rom

#mkisofs /dev/cdrom -o /temp/songs3.iso



Method2: Creating an iso image from a folder



Suppose i am having a folder /opt/data which contains some data to be converted in to .iso file, follow below step



#mkisofs -o /temp/songs4.iso /opt/data



Q. How to mount an ISO file?



Ans: #mount -o loop /temp/songs4.iso /opt/mountpoint



Q. How to unmount an ISO file?



Ans: #umount -lf /opt/mountpoint


Comments

Post a Comment

Popular posts from this blog

Docker ,MakeFile and Jenkins pipeline

-
How to create a re-usable MakeFile for build, push and deploy docker containers? and automate build using Jenkins pipeline.? Typing a long docker commands is always a pain.We can create a script to help us out. Bash can be used here, but using a Makefile for more convenient than script, as the syntax is easy to get started with. Clone below repo [ MakeFile_repo ] and go to the directory.  git clone git@github.com:Prashanth-Pullaikodi/Makefile_Docker_Build.git Repo contains below files and folders. 1. MakeFile: Contains make configuration to build, push and deploy containers. Inorder to run the make command you needs to have docker installed and docker hub account . 2. Nginx: Contains Dockerfile to build NGINX . 3. Jenkinsfile: Contains CD pipile line defintion of automating this build ,push deploy task. Inorder have to use this file you needs to have Jenkins installed and configured with pipeline ,Git plugins. You can use Makefile without Jenkins as well . Makefile
Read more

Networking Basics

-
Q. What is Network? Ans: A network is simply a collection of computers or other hardware devices that are connected together, either physically or logically, using special hardware and software, to allow them to exchange information and cooperate. Networking is the term that describes the processes involved in designing, implementing, upgrading, managing and otherwise working with networks and network technologies. Q. What are The Advantages (Benefits) and Disadvantages (Costs) of Networking? Ans: Most of the benefits of networking can be divided into two generic categories: connectivity and sharing. Networks allow computers, and hence their users, to be connected together. They also allow for the easy sharing of information and resources, and cooperation between the devices in other ways. Since modern business depends so much on the intelligent flow and management of information, this tells you a lot about why networking is so valuable. Here, in no particular o
Read more

Continuous Deployment - Jenkins , Capistrano And Docker.

-
How to integrate Capistrano with Docker for deployment? Lets start with small introduction about 'Capistrano' . Capistrano is a framework for building automated deployment scripts on remote node.Its an open source tool which is written in Ruby, but it can easily be used to deploy any language. Basically capistrano installed to and runs from your working computer. When you command Capistrano to do something on a server, it connects to the server via SSH and works there using shell commands. Lets see how the directory structure of capistrano looks like.If you are running capistrano first time ,you run below commands to initialise it,Which will create directory structure for you. $ mkdir capistrano/ $ cd capistrano/ $ cap install - mkdir -p config/deploy - create config/deploy.rb - create config/deploy/staging.rb - create config/deploy/production.rb - mkdir -p lib/capistrano/tasks - create Capfile - Capified To understand m
Read more