Sunday 5 February 2017

Linux Desktop Environments & Productivity Softwares

Linux Desktop Environment


Linux creates a friendly environment for choices and options. For example, there are many Linux-based distributions out there that use different desktop environments for you to choose from. I have picked some of the best desktop environments that you will see in the Linux world.

Plasma

I consider KDE’s Plasma desktop to be the most advanced desktop environment (DE). It’s the most feature-rich and customizable desktop environment that I have ever seen; even Mac OS X and Windows don’t come near Plasma when it comes to complete control by the user.
I also love Plasma because of its awesome file manager, Dolphin. One reason I prefer Plasma over Gnome-based systems is the file manager. One of my biggest gripes with Gnome is that its file manager, Files, can’t handle basic tasks, such as batch-files renaming. That’s important for me because I take a lot of pictures, and Gnome makes it impossible for me to rename image files. On Dolphin, it’s a walk in the park.
Then, you can add more functionality to Plasma with plugins. Plasma comes with some incredible software including Krita, Kdenlive, Calligra Office Suite, digiKam, Kwrite, and many other applications being developed by the KDE community.
The only weakness of the Plasma desktop is its default email client, Kmail. It’s way too complicated to set up, and I also wish that setting up Kmail also configured the Address Book and Calendar.
Plasma is the default desktop environment of many major distributions including openSUSE.


GNOME

GNOME (GNU Network Object Model Environment) was founded by Miguel de Icaza and Federico Mena in 1997 because KDE used Qt toolkit, which was released under a proprietary license. Unlike KDE, where there were numerous customizations, GNOME focused on keeping things simple. GNOME became extremely popular due to its simplicity and ease of use. A factor that I think contributed heavily to Gnome’s popularity was the fact that Ubuntu, one of the most popular Linux distributions, picked it as their default desktop environment.
With changing times, GNOME needed a change. Therefore, with GNOME 3 the developers introduced the GNOME 3 Shell, which brought with it an entirely new design paradigm. That in turn led to some conflict with Canonical’s plans with Ubuntu, and they created their own shell for GNOME called Unity. Initially, GNOME 3 Shell was plagued by many issues -- most notably, the fact that extensions would stop working after updates. This major shift in design and the various problems then led to many forks of GNOME, such as the Cinnamon and Mate desktops.
That said, what makes GNOME desktop interesting is that they are targeting touch-based devices, so if you have new laptops that come with a touchscreen, Gnome is the best suited DE for them.
With version 3.18, GNOME has made some impressive improvements. The most interesting thing that they have done is Google Drive integration where users can mount their Google Drive as a remote file storage and work with files without having to use a web browser. I also love GNOME’s awesome integration of email client with calendar and address book. Despite all this awesomeness, however, the one thing that keeps me from using GNOME is its file manager, which can’t handle batch file renames. I will stick to Plasma until GNOME developers fix this problem.

Unity

Unity is technically not a desktop environment, it’s a graphical shell developed by Canonical for Ubuntu. Unity runs on top of GNOME desktop environment and uses most stock GNOME apps and tools. The Ubuntu team has forked a few GNOME components to better suit the needs of Unity users.
Unity plays a very important role in Ubuntu’s convergence story and with Unity 8, the company is bringing the desktop and mobile world together. Canonical has developed many intriguing technologies for Unity including HUD (Head-up Display). They also took a unique approach with lenses and scopes making it easy for users to find appropriate content.
The upcoming release of Ubuntu, 16.04, is expected to ship with Unity 8 so users will get to experience all the work that developers have put into this open source software. One of the biggest criticisms with Unity was opt-out integration of Amazon ads and other services. With the upcoming release, though, Canonical is removing Amazon ads from Dash, making it a privacy-respecting OS by default.

Cinnamon

Cinnamon was initially developed by Linux Mint -- the most popular distro on DistroWatch. Cinnamon is a fork of GNOME Shell, just like Unity. Later, however, it evolved into a desktop environment as Linux Mint developers forked many components of the GNOME desktop, including Files, to address the needs of their users.
Because Linux Mint was based on regular releases of Ubuntu, the developers continued to chase the moving target that was Ubuntu. As a result, despite great promises Cinnamon was full of bugs and problems. With the 17.x release, however, Linux Mint developers moved to LTS edition of Ubuntu that allowed them to focus on core components of Cinnamon without having to worry about the base. As a result of this move, Cinnamon has become incredibly stable and bug free. The developers have started adding more features to the desktop.
For those who prefer the good old Windows-like UI on top of the simplicity of GNOME, Cinnamon is the best desktop environment.

MATE Desktop

The MATE desktop environment is also a fork of GNOME. However, unlike Cinnamon, it’s not a fork of GNOME 3; instead it’s a fork of GNOME 2 codebase, which is not unmaintained. A few developers didn’t like Gnome 3 and wanted to “continue” GNOME 2, so they took the codebase and created MATE. The MATE project forked many components of the GNOME project and created a few from scratch. To avoid any conflict with GNOME 3, they renamed all their packages: Nautilus become Caja, Gedit became Pluma, Evince became Atril, and so on.
Although MATE is a continuation of GNOME 2, that doesn’t mean they are using old and obsolete technologies; they are using newer technologies to offer a modern GNOME 2 experience.
What makes MATE an impressive desktop environment is that it’s extremely resource efficient. You can run it on older hardware or newer less powerful hardware, such as Raspberry Pi or Chromebook Flip. What’s makes it even more interesting is that using it on powerful systems frees most system resources for applications instead of the resources being consumed by the desktop environment itself.

LXQt

LXQt is the successor of LXDE, one of the most lightweight desktop environments. It’s a merger of two open source projects LXDE and Razor-Qt. The first usable version of LXQt (v 0.9) was released in 2015. Initially, the developers used Qt4 but then all compatibility with it was dropped, and they moved to Qt5 and KDE Frameworks 5 for speedy development. I have tried LXQt on my Arch systems, and its a great lightweight desktop environment, but it has a long way to go before it becomes the rightful successor of LXDE.

Xfce

Xfce predates the KDE desktop environment. It is one of the oldest and lightest desktop environments around. The latest release of Xfce is 4.15, which was released in 2015 and uses modern technologies like GTK+ 3. Xfce is used by many special purpose distributions, such as Ubuntu Studio, because -- much like MATE -- it frees most system resources for applications. It’s also the default desktop environment of many notable Linux distributions including Manjaro Linux, PC/OS, Salix, and Mythbuntu.

Budgie

Budgie is a new desktop environment being developed by the Solus Linux team. Solus is new Linux distribution that’s being developed from scratch, and Budgie is a core component of it. Budgie uses many GNOME components and offers a minimalistic UI. Because there’s not much information about the new desktop, I talked to the core developer of Solus, Ikey Doherty, and he explained, “We ship our own desktop, the Budgie Desktop. Unlike some other desktops, this is not a fork, rather it aims for full integration into the GNOME stack. It's written from scratch, and is specifically designed to cater for the experience Solus is offering. We work with upstream GNOME here as much as we can, contributing fixes, and advocate and support their work.”

Pantheon

Pantheon needs no introduction, it’s the desktop environment powering the lovely Linux distribution elementary OS. Similar to Budgie, Pantheon is not a fork of GNOME as many may assume. elementary OS team comes from design background so they pay very close attention to minute details, as a result Pantheon is extremely polished desktop environment. At the moment, it may lack many feature found in DEs like Plasma, but the developers are taking their time in order to stick to the design principle.

Conclusion

As I went through this story, I realized the awesomeness of open source and Linux. There is something for everyone. As Jon “maddog” Hall said during the latest SCaLE 14, “Yes, there are 300 Linux distributions. I can try them and stick to the one that I like!”
So, enjoy this diversity and use the one that floats your boat!

Productivity Softwares
Common wisdom says that Linux lacks applications fortunately, the common wisdom is dead wrong on this, especially when it comes to productivity applications. Finding the applications, though, can be a challenge — so I've put together a list of 10 great, and free, productivity apps for the Linux desktop.
Now, when I refer to "productivity tools," I'm talking about tools that go with time management, calendaring, note-taking, task-management and office tools. If you haven't been on Linux very long, you might not realize what a wide selection and variety of tools you have to choose from. This is by no means a fully exhaustive list, but a selection of tools for the Linux desktop that I've found useful over the years.

LibreOffice

We have to start with the most obvious, simply because LibreOffice is the de facto standard office suite for Linux. Most likely, your distribution comes pre-installed with this open source suite of tools that includes a word processor, spreadsheets, presentations, formula generator, database, and a drawing tool.


Little can be said of LibreOffice that hasn’t already been said; but if you’re looking at implementing Linux in the office, your best choices on this level fall to either LibreOffice or Google Docs. For those that prefer local apps, you’re left with LibreOffice...and that’s not such a bad thing. In fact, LibreOffice outshines MS Office in a number of ways. Above all else, LibreOffice follows standards far better than MS Office. LibreOffice is also free to use, so anyone on a budget won’t have to dig deep into their pockets for a subscription to Office365. LibreOffice has an outstanding extension system and a wonderful centralized interface Start Center ,where you can open previously saved documents or start something new.

Google Keep

There are plenty of note-taking apps available for Linux. But, if you’re looking for a note-taking app that makes syncing to the cloud (so you can use your notes anywhere), you’d be hard-pressed to find a better tool than Google Keep. I know what you’re saying, “Google Keep is just a web page and not a Linux app.” To that, I would say you are only partially correct. If you happen to use Chrome on Linux, you can install the Google Keep extension and then open Keep in its own app window .
Google Keep allows you to take notes, create bulleted lists, share notes, add images, extract text from images, and much more.

Evolution

If you’re looking for a Personal Information Manager (PIM), and you’ve migrated from MS Outlook, you’ll want to give Evolution a look. Evolution has come a long, long way and when paired with the likes of Ubuntu GNOME, it makes for an amazing productivity tool. And, with an ease of integration into the likes of Google apps (Mail, Calendar, Contacts, Tasks), you won’t find a more productive PIM within the Linux landscape. When using Evolution with the latest iteration of GNOME, all you have to do is add your Google account to the On-Line Accounts section of Settings, and Evolution will automatically start syncing upon first run.
For a very long time, Evolution was frowned upon for being buggy. The latest releases are quite stable and do an outstanding job of working with Google and Exchange 2007/2010.

GIMP

Another obvious choice for productivity happens to be the flagship image editor for the Linux platform. GIMP is a powerhouse image editing tool that will serve anyone (regardless of platform) needing to add this functionality to their productivity. GIMP can handle anything you throw at it...and more. If you’re looking for the Photoshop for Linux...this is it.
One of the wonderful things about GIMP is that the developers listen. For the longest time, the GIMP interface was a problem for many users. To change that, the developers created Single Window Mode . Even many of us long-time users decided it was a more efficient means of working with images.


GNOME Files

This one is tricky. Why? Because everyone uses a file manager and everyone’s idea of a good file manager varies, depending upon their needs. Even though I am an Elementary OS Freya user, I find the default file manager for GNOME to be superior...even if for only two features. Nautilus includes entries for Move to and Copy to in the context menus (Figure 5). This makes moving or copying files to a new location incredibly easy.
The second feature that helps GNOME Files rise above the rest is the ease of file/folder sharing. Getting some file managers to work with Samba requires significant work. GNOME Files works out of the box with Samba, so your network file sharing is simple.
Yes, there are tons of outstanding file managers for Linux, but if you’re looking for the one that will help boost your productivity, without requiring you to learn an entirely new interface or jump through hoops, GNOME Files might be the one.

Tweak Tools

By default, Ubuntu doesn’t provide a lot of flexibility when it comes to customizing your desktop experience. You can do things like change your wallpaper, use different fonts for your system, and install different window themes, but not much more than that.
If you want nitty-gritty access to some of the more advanced settings hidden beneath the hood of your system, you’ll want to install a tweak tool. The one you choose will depend on your desktop environment.

For Unity desktops: You should install Unity Tweak Tool, which is available in the Software Center. This will let you change the behavior of windows and settings beyond what Unity normally allows.



For Gnome desktops: You should install Gnome Tweak Tool, which can also be found in the Software Center. Advanced tweaks include custom keyboard shortcuts, altered window behaviors, and fine-grain theme controls.
For Compiz desktops: Compiz isn’t a desktop environment per se, but rather a window manager that allows for 3D effects and animations. If you decide to use Compiz for window management, you should install Compiz Config Settings Manager from the Software Center.
Compiz is far more advanced than the other tweak tools above, which means it might be overwhelming at first. Be careful not to change things unless you know what they are, otherwise you may break something.

Synaptic Package Manager

Except for the tweak tools above, I’m convinced that there’s no tool more important for Ubuntu users than Synaptic Package Manager. Sure, the built-in Ubuntu Software Center is good enough to get the job done, but it has a few quirks and missing features.On the other hand, Synaptic is objectively better. For starters, it isn’t as laggy when browsing through packages, and it’s way faster at returning search results. It can repair broken package dependencies, perform smart system upgrades, and has a friendlier interface.
Plus, it has a setting for automatically deleting packages after installation, which helps alleviate unnecessary disk space usage. Ubuntu Software Center doesn’t have this feature.

Sublime Text

One of the worst Linux myths is that only programmers should care about Linux. This myth does a disservice to the operating system because there’s a lot to like about Linux even if you’ve never seen or written a line of code in your life.That being said, it’s undeniable that Linux is great for programmers, and if you’re going to be doing any kind of programming or scripting at all, then you should really consider installing Sublime Text. It’s the best text editor out there and almost as good as an IDE.
How to install: Sublime Text is not available in the Software Center. To install, open the Terminal and type in the following three commands:
sudo add-apt-repository ppa:webupd8team/sublime-text-3
sudo apt-get update
sudo apt-get install sublime-text-installer

Steam

Linux is becoming a serious platform for gaming. It hasn’t gotten there yet, but it’s well on its way, and there’s a lot of evidence to show that Linux may catch up to Windows in just a few more years. One of the biggest milestones? The release of Steam for Linux.Steam is one of the best ways to download games on Linux. The library of games is expansive, the community is massive, and the games themselves are pretty darn good. Not all of the games on Steam can be played just yet, but the number that can be played is growing day by day, and Steam itself is always improving too.
For now, you’ll have to deal with the fact that many games — such as these free MMORPGs that are native to Linux — will have to be played outside of Steam.

Bluefish
If you need a programming and Web content editor that’s really sophisticated but lightweight and flexible, you have to check out Bluefish. What I really like about Bluefish is it loads fast, supports projects (groups of files), has auto-completion and auto-tag closing, understands many programming languages, and includes site upload and download ability. And that’s just scratching the surface of what Bluefish can do.

Wine

Linux has some awesome apps, but sometimes the big guys ignore Linux and we’re left out in the cold. Wine is (sometimes) the answer: if you’ve got a Windows program you can’t leave behind (whether it’s Outlook for work, Photoshop for images, or World of Warcraft for fun), Wine will run it on your Linux desktop. It doesn’t work with every program out there, but Wine’s app database will help you figure out which ones work well, so you can get one step closer to leaving Windows behind forever.

Tuesday 31 January 2017

Commercial Linux vs Open Source Linux

Commercial Linux 



Many people might have no idea about Commercial Linux Distribution. Some think that it is like Microsoft or Apple. NO but it is different, Commercial Linux Distribution is free to use but if you want their support you need to pay.
Best example for Commercial Linux is Redhat Linux, it is free to use it, But if you need their support you have to pay for it.
There are million of companies use linux in their server system and also many educational institute use linux based server. 
These  Server system are difficult to configure for a individual so for that purpose there is Commercial linux Distribution.
If you are using Commercial linux Distribution for free and if you stuck with any problem in the linux Distribution you can subscribe it and take their help. 

CentOS / Red Hat Enterprise Linux

Red Hat Enterprise Linux is a commercial Linux distribution intended for servers and workstations. It’s based on the open-source Fedora project, but is designed to be a stable platform with long-term support.
Red Hat uses trademark law to prevent their official Red Hat Enterprise Linux software from being redistributed. However, the core software is free and open-source. CentOS is a community project that takes the Red Hat Enterprise Linux code, removes all Red Hat’s trademarks, and makes it available for free use and distribution. It’s a free version of RHEL, so it’s good if you want a stable platform that will be supported for a long time. CentOS and Red Hat recently announced they’re collaborating, so CentOS is now part of Red Hat itself.


Open Source Linux

Ubuntu

Ubuntu is probably the most well-known Linux distribution. Ubuntu is based on Debian, but it has its own software repositories. Much of the software in these repositories is synced from Debian’s repositories.
The Ubuntu project has a focus on providing a solid desktop (and server) experience, and it isn’t afraid to build its own custom technology to do it. Ubuntu used to use the GNOME 2 desktop environment, but it now uses its own Unity desktop environment. Ubuntu is even building its own Mir graphical server while other distributions are working on the Wayland.
Ubuntu is modern without being too bleeding edge. It offers releases every six months, with a more stable LTS (long term support) release every two years. Ubuntu is currently working on expanding the Ubuntu distribution to run on smartphones and tablets.

Mint is a Linux distribution built on top of Ubuntu. It uses Ubuntu’s software repositories, so the same packages are available on both. Originally Mint was an alternative distribution loved mainly because it included media codecs and proprietary software that Ubuntu didn’t include by default.
This distribution now has its own identity. You won’t find Ubuntu’s own Unity desktop here — instead, you get a more traditional Cinnamon or MATE desktop. Mint takes a more relaxed approach to software updates and won’t automatically install critical software updates. Controversially, this has led some Ubuntu developers to label it insecure.

Debian

Debian is an operating system composed only of free, open-source software. The Debian project has been operating since 1993 — over 20 years ago! This widely respected project is still releasing new versions of Debian, but it’s known for moving much more slowly than distributions like Ubuntu or Linux Mint. This can make it more stable and conservative, which is ideal for some systems.
Ubuntu was originally founded to take the core bits of stable Debian and improve on them more quickly, packaging the software together into a user-friendly system that’s more frequently updated.

Fedora

Fedora is a project with a strong focus on free software — you won’t find an easy way to install proprietary graphics drivers here, although third-party repositories are available. Fedora is bleeding edge and contains the latest versions of software.
Unlike Ubuntu, Fedora doesn’t make its own desktop environment or other software. Instead, the Fedora project uses “upstream” software, providing a platform that integrates all this upstream software without adding their own custom tools or patching it too much. Fedora comes with the GNOME 3 desktop environment by default, although you can also get “spins” that come with other desktop environments.
Fedora is sponsored by Red Hat, and is the foundation for the commercial Red Hat Enterprise Linux project. Unlike RHEL, Fedora is bleeding edge and not supported for long. If you want a more stable release that’s supported for longer, Red Hat would prefer you use their Enterprise product.

openSUSE / SUSE Linux Enterprise

openSUSE is a community-created Linux distribution sponsored by Novell. Novell purchased SuSE Linux in 2003, and they still create an enterprise Linux project known as SUSE Linux Enterprise. Where Red Hat has the Fedora project that feeds into Red Hat Enterprise Linux, Novell has the openSUSE project that feeds into SUSE Linux Enterprise.
Like Fedora, openSUSE is a more bleeding edge version of Linux. SUSE was once one of the great user-friendly desktop Linux distributions, but Ubuntu eventually took that crown.

Mageia / Mandriva

Mageia is a fork of Mandriva Linux created in 2011. Mandriva — known as Mandrake before that — was once one of the great user-friendly Linux distributions.
Like Fedora and openSUSE, this is a community-created project to create an open-source Linux distribution. Mandriva SA no longer creates a consumer Linux distribution for desktop PCs, but their business Linux server projects are based on Mageia code — just like how Fedora and openSUSE provide code to their enterprise equivalents.

Arch Linux

Arch Linux is more old school than many of the other Linux distributions here. It’s designed to be flexible, lightweight, minimal, and to “Keep it Simple.” Keeping it simple doesn’t mean Arch provides tons of graphical utilities and automatic configuration scripts to help you set up your system. Instead, it means Arch dispenses with that stuff and gets out of your way.
You’re in charge of configuring your system properly and installing the software you like. Arch doesn’t provide an official graphical interface for its package manager or complex graphical configuration tools. Instead, it provides clean configuration files designed for easy editing. The installation disc dumps you at a terminal, where you’ll need to enter the appropriate commands to configure your system, partition your disks, and install the operating system yourself.
Arch uses a “rolling release” model, which means any installation image is just a snapshot of the current software. Every bit of software will be updated over time without you needing to upgrade to a new “release” of Arch.
This distribution has a bit in common with Gentoo, which was popular at one time. Both Linux distributions are designed for users who know how their systems work or who are at least willing to learn. However, Arch uses binary packages while Gentoo had an (unnecessary) focus on compiling every bit of software from source — this means it’s quick to install software on Arch as you don’t have to spend CPU cycles and time waiting for software to compile.

Slackware Linux

Slackware is another institution. Founded in 1993, Slackware is the oldest Linux distribution that’s still maintained and putting out new releases today.
Its pedigree shows — like Arch, Slackware dispenses with all those unnecessary graphical tools and automatic configuration scripts. There’s no graphical installation procedure — you’ll have to partition your disk manually and then run the setup program. Slackware boots to a command-line environment by default. It’s a very conservative Linux distribution.

Puppy Linux


Puppy Linux is another fairly well-known Linux  distribution. Previous versions have been built 
on Ubuntu, but the latest is built on Slackware. Puppy is designed to be a small, lightweight operating system that can run well on very old computers. The puppy ISO file is 161 MB, and Puppy can boot from that disc in a live environment. Puppy can run on PCs with 256 MB or RAM, although it does recommend 512 MB for the best experience.

Puppy isn’t the most modern and doesn’t have all the flashiest bells and whistles, but it can help you revive an old PC.

These aren’t the only Linux distributions out there.  Distrowatch lists many and tries to rank them by popularity.



                      The choice is yours 


Linux Boot Process


1.BIOS(Basic Input/Output System)
        2.MBR(Master Boot Record)
        3.LILO or GRUB
            LILO:-LInux LOader
            GRUB:-GRand Unified Bootloader
        4.Kernel
        5.init
       6.Run Levels
1.BIOS:
     i.When we power on BIOS performs a Power-OSelf-Test (POST) for all of the different hardware components in the system to make sure everything is working properly
     ii.Also it checks for whether the computer is being started from an off position (cold boot) or from a restart (warm boot) is
stored at this location.
     iii.Retrieves information from CMOS (Complementary Metal-Oxide Semiconductor) a battery operated memory chip on the motherboard that stores time, date, and critical system information.
     iv.Once BIOS sees everything is fine it will begin searching for an operating system Boot Sector on a valid master boot sector
on all available drives like hard disks,CD-ROM drive etc.
     v.Once BIOS finds a valid MBR it will give the instructions to boot and executes the first 512-byte boot sector that is the first
sector (“Sector 0″) of a partitioned data storage device such as hard disk or CD-ROM etc .
2.MBR
     i. Normally we use multi-level boot loader.Here MBR means I am referencing to DOS MBR.
     ii.Afer BIOS executes a valid DOS MBR,the DOS MBR will search for a valid primary partition marked as bootable on the hard disk.
     iii.If MBR finds a valid bootable primary partition then it executes the first 512-bytes of that partition which is second level MBR.
     iv. In linux we have two types of the above mentioned second level MBR known as LILO and GRUB
3.LILO
     i.LILO is a linux boot loader which is too big to fit into single sector of 512-bytes.
    It is divided into two parts :an installer and a runtime module.
     iii.The installer module places the runtime module on MBR.The runtime module has the info about all operating systems installed.
     iv.When the runtime module is executed it selects the operating system to load and transfers the control to kernel.
     v.LILO does not understand filesystems and boot images to be loaded and treats them as raw disk offsets
GRUB
     i.GRUB MBR consists of 446 bytes of primary bootloader code and 64 bytes of the partition table.
     ii.GRUB locates all the operating systems installed and gives a GUI to select the operating system need to be loaded.
     iii.Once user selects the operating system GRUB will pass control to the karnel of that operating system.
See below what is the difference between LILO and GRUB
The original file is /etc/grub.conf of which you can observe a symlink file at /boot/grub/grub.conf

Sample /boot/grub/grub.conf
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title Red Hat Enterprise Linux Server (2.6.18-194.26.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.26.1.el5 ro root=/dev/VolGroup00/root clocksource=acpi_pm divisor=10
        initrd /initrd-2.6.18-194.26.1.el5.img

title Red Hat Enterprise Linux Server (2.6.18-194.11.4.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.11.4.el5 ro root=/dev/VolGroup00/root clocksource=acpi_pm divisor=10
        initrd /initrd-2.6.18-194.11.4.el5.img
title Red Hat Enterprise Linux Server (2.6.18-194.11.3.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-194.11.3.el5 ro root=/dev/VolGroup00/root clocksource=acpi_pm divisor=10
        initrd /initrd-2.6.18-194.11.3.el5.img


4.Kernel
     i.Once GRUB or LILO transfers the control to Kernel,the Kernels does the following tasks

  • Intitialises devices and loads initrd module
  • mounts root filesystem
5.Init
     i.The kernel, once it is loaded, finds init in sbin(/sbin/init) and executes it.
     ii.Hence the first process which is started in linux is init process.
     iii.This init process reads /etc/inittab file and sets the path, starts swapping, checks the file systems, and so on.
     

  • Executes the system to boot into the run level as specified in /etc/inittab
Sample output defining the default boot runlevel inside /etc/inittab
# Default runlevel. The runlevels used by RHS are:
#   0 - halt (Do NOT set initdefault to this)
#   1 - Single user mode
#   2 - Multiuser, without NFS (The same as 3, if you do not have networking)
#   3 - Full multiuser mode
#   4 - unused
#   5 - X11
#   6 - reboot (Do NOT set initdefault to this)
#
id:5:initdefault:
6.Runlevel
     i.There are 7 run levels in which the linux OS runs and different run levels serves for different purpose.The descriptions are
given below.

  • 0  – halt
  • 1  – Single user mode
  • 2  – Multiuser, without NFS (The same as 3, if you don’t have networking)
  • 3  – Full multiuser mode
  • 4  – unused
  • 5  – X11
  • 6  – Reboot
     ii.We can set in which runlevel we want to run our operating system by defining it on /etc/inittab file.


Below are given some few  important differences about LILO and GRUB
LILO
GRUB
LILO has no interactive command interfaceGRUB has interactive command interface
LILO does not support booting from a networkGRUB does support booting from a network
If you change your LILO config file, you have to rewrite the LILO stage one boot loader to the MBRGRUB automatically detects any change in config file and auto loads the OS
LILO supports only linux operating systemGRUB supports large number of OS