Tuesday, February 7, 2017

Productivity software

About Productivity Softwares

     
           Productivity software are those softwares that make computer useful. Productivity software is a category of application programs that help users produce things such as documents, databases, graphs, worksheets and presentations. 
        Many productivity applications are intended for business use. Examples of office productivity software include word processors, database management systems (DBMS), graphics software and spreadsheet applications. The definition of productivity software is sometimes broadened to include any type of application that is used to help people do their jobs, including collaboration and communication programs.
         Productivity software, like most types of applications, is increasingly available for mobile devices. However, mobile productivity apps are generally for basic tasks like e-mail, note-taking and calendar functions, rather than more substantial tasks, such as word processing.


WebBrowsers



Firefox 
       This program, headquartered at http://www.mozilla.org , is the most popular browser for Linux, and is also quite popular on Windows and Mac OS X. It’s a very complete browser, but it can consume a lot of memory, so it may not be the best choice on an older or weaker computer.

Galeon 
        This program, headquartered at http://galeon.sourceforge.net , is a browser that’s officially part of the GNOME Office suite. It’s designed as a lightweight GUI Web browser.

Konqueror
         This KDE program serves a dual function: It’s both a Web browser and a file manager. Konqueror does a good job with most Web pages. It’s fairly lightweight, and so is well worth trying, particularly if you use KDE.


Multimedia Apps



Audacity 
       This program, based at http://audacity.sourceforge.net , is an audio editor for Linux, similar to commercial products like Sound Forge for other platforms. You can use it to cut sections from an audio file, equalize volume, remove tape hiss or other noises, apply artificial audio effects, and more.

HandBrake  
       This program provides an easy way to convert between video formats, and particularly into formats that use the efficient H.264 encoding.

GIMP
        The GNU Image Manipulation Program (GIMP; http://www.gimp​.org ) is a still image manipulation program similar in broad strokes to Adobe Photoshop. (The GTK+ toolkit, which is the basis of GNOME and many other programs, was originally created for the GIMP.)



Linux Desktop Environments

About Desktop Environments

            Possibly, your first encounter with a Linux System could be desktop environment. A Desktop Environment is a set of programs that control the screen and provide small utility programs to perform tasks such as manage files. Moreover unlike Windows or MAC OS X, Linux provides multiple Desktop environment options, so if you don’t like one you can choose another.

Popular Desktop Environments

1) GNOME

GNOME is developed by The GNOME Project and provides the GNOME Desktop Environment, a graphical user interface and a set of core applications, and the GNOME Development Platform, a framework for building applications that integrate with the desktop.

Features:
  • Completely open source
  • Uses Metacity as default window manager
  • Comes with Nautilus as default file manager
  • Supports desktop notifications using a convenient messaging system
  • Enables on/off switching of desktop notifications and many more



2) KDE

           The K Desktop Environment (KDE; http://www.kde.org ) is one of the
most popular desktop environments for Linux. It’s the default desktop environ-
ment for Mandriva and SUSE. It includes many powerful tools that integrate
together very well.

Features:
  • Optional Menus
  • Web Shortcuts. ...
  • Accessibility Tools. ...
  • K3B CD/DVD Ripper. ...
  • Optional System Setting Displays. ...
  • Rotating Icons and Widgets. ...
  • Multiple Clipboard. ...
  • Customizable Virtual Workspaces.

3) Or simply Roll your own

          It’s possible to build a desktop environment of your own from components you like. At a minimum, you need a window manager (dozens are available; see http://xwinman.org for a partial list), but for the configuration to truly be a desktop environment, you’ll need other components, such as a file manager and small productivity tools. All of the components need to be accessible from some sort of menu system.



Conclusion

   New users who are accustomed to Windows or Mac OS will probably be happiest with KDE; this environment is most like these traditional desktop operating systems’ environments. Although they deviate more from the model used by other OSs, GNOME and Unity aim for ease of use and so can be good choices for the inexperienced. Users who are familiar with commercial Unix OSs might give Xfce a try. Xfce and LXDE are good choices on systems that have less than copious RAM or less than blazing CPUs. People who like to customize everything or who have less-capable computers should investigate the roll-your-own approach.

Wednesday, February 1, 2017

Linux Boot Process

The Linux Boot process works as follows

Power on

BIOS (Basic Input Output System) is a software program comes pre-built in a motherboard chipset.
BIOS loads and scans for devices such as Hard Disk, CD-ROM, RAM, etc.
BIOS searches for MBR (Master Boot Record: 1st sector) of the primary hard drive, it scans for 1st stage loader (In our case boot loader is (GRUB LILO) and hands over the responsibility to MBR.
Boot PROM/FLASH/BIOS is proficient of loading the MBR into RAM and executing it.


MBR (Master Boot Record)

512 bytes of space –> MBR
MBR contains the information of loader of most operating system e.g UNIX, Linux and WINDOWS
MBR holds the small binary information of 1st stage of loader
MBR consist physical sector of the first disk drive (i.e 512 bytes) and it’s not part of any partition.
Placed on the prime disk drive, in the prime sector of the first cylinder of track is 0 and head is 0 (this whole path is generally booked for boot programs)
MBR involve a mini executable programs and a table specify the primary partitions.

Boot Loader

The boot loader termed from 1st stage loader and loads itself into RAM. All this go on in milliseconds.
The default stage 2 boot loader is a GRUB (Grand Unified Boot Loader) or LILO (Linux Loader)
Once GRUB is loaded into RAM, then it’s search for the location of Kernel.
GRUB will scrutinize the map file to find the kernel image, that is located under (/boot) and load it.
GRUB loads the kernel (vmlinuz-version) from /boot partition

Kernel


Mounts the root file system as specified in the “root=” in grub.conf
Kernel executes the /sbin/init program
Since init was the 1st program to be executed by Linux Kernel, it has the process id (PID) of 1. Do a ‘ps -ef | grep init’ and check the pid.
initrd stands for Initial RAM Disk.
initrd is used by kernel as temporary root file system until kernel is booted and the real root file system is mounted. It also contains necessary drivers compiled inside, which helps it to access the hard drive partitions, and other hardware.


Init

Init identifies the default initlevel from /etc/inittab and uses that to load all appropriate program.
Execute ‘grep initdefault /etc/inittab’ on your system to identify the default run level
If you want to get into trouble, you can set the default run level to 0 or 6. Since you know what 0 and 6 means, probably you might not do that.

Runlevel

When the Linux system is booting up, you might see various services getting started. For example, it might say “starting sendmail …. OK”. Those are the runlevel programs, executed from the run level directory as defined by your run level.
Under the /etc/rc.d/rc*.d/ directories, you would see programs that start with S and K.
Programs starts with S are used during startup. S for startup.
Programs starts with K are used during shutdown. K for kill.