Tuesday 31 January 2012

Linux Installation Methods

Linux Installation Methods
  • FTP server across the network
  • HTTP Web server across the network
  • NFS server across the network
  • SMB server across the network
  • Virtual Network Computing (VNC) server across the network
  • From packages located on the hard disk
  • Installation from one or more CD-ROMs 
Disk Partitioning in Linux  
  • Partitions are slices of the hard drive. Typically an installation of Linux will create these slices or partitions of a hard drive.
  • These partitions create separate areas of the disk to hold multiple operating systems or to separate programs and data to aid in back-up.
  • The first sector 0 is reserved for the master boot record. The master boot record on the Primary Boot Drive, contains the mapping for all partitions on all drives.  
Reasons For Creating Multiple Partitions  
  • Multiple operating systems – more than one OS installed.
  • Multiple partitions within an operating system-many partition is created.
  • Different file system types – more than one file system type ex:NTFS and FAT32.
Partition for root director
  • The root file system is represented by a forward slash (/).
  • It is the top of the directory tree, and contains Linux and everything that you install with Linux.
  • The size of your root partition will vary depending on what you install or plan to install.
     Partition for home directory 

  • The third and final partition you should create will hold your /home directory.
  • This is the place where all the user-specific files, your data in other words, are stored.
  • It is roughly equivalent to the "My Documents" folder on a MS Windows desktop (if you have MS Office installed). On a multi-user system, each user will have her own directory under /home. 
     Linux File System 
    /boot : contains everything required for the boot process except configuration files. Stores data that is used before the kernel begins executing user-mode programs.
    /homeA fairly standard concept, but it is clearly a site-specific filesystem.The setup will differ from host to host. Therefore,no program should rely on this location. 
    /usr Programs, libraries, documentation etc. for all user-related programs.
    /opt : Reserved for the installation of add-on application software packages.
    /var : Contains variable data files. This includes spool directories and files, administrative and logging data, and transient and temporary files.
    /tmp : /tmp directory must be made available for programs that require temporary files. 
    Partitioning methods 
    • Automatically partition
    • Manual partitioning with graphical partitioning tools such as disk druid
    • Use fdisk utility
    • GNU parted 
     Boot Loaders in Linux 
    • A boot loader, also called a boot manager, is a small program that places the operating system (OS) of a computer into memory. 
    • Responsible for loading and transferring control to the operating system kernel software.
    • When a computer is powered-up or restarted, the basic input/output system (BIOS) performs some initial tests, and then transfers control to the master boot record (MBR) where the boot loader resides.
     Linux Loader (LILO)
    • Does not depend on a specific file system, and can boot an operating system from floppy disks and hard disks.LILO can be placed either in the master boot record (MBR) or the boot sector of a partition.
    Grand Unified Bootloader (GRUB)
    • Provides a user the choice to boot one of multiple operating systems installed on a computer or select a specific kernel configuration available on a particular operating system's partitions.
    Loadlin 
    • It allows the Linux system to load and replace the running DOS/Windows without altering existing DOS/Windows system files.
    Syslinux 
    • A suite of lightweight IBM PC MBR bootloaders for starting up computers with the Linux kernel.It consists of several separate systems, the best-known of which is ISOLINUX.

    Thursday 12 January 2012

    Introduction To Open Source Software (OSS) Technology

    History of Open Source

    1. Richard Stallman has launched the GNU Project and the Free Software Foundation.

     Richard Stallman

          2. The Ultimate goal of the GNU Project was :
    • To build a free operating system
    • Coding some programming tools (Compiler, Editor, etc.)
    Example of  Open Source Software:



                                  



    OSS Web Resources

    1. OSS websites & repository
         - It refers to a central place where data is stored and maintained. 
    •      A repository can be a place where multiple databases or files are located for distribution over a network.
    •      A repository can be a location that is directly accessible to the user without having to travel across a network.
    2. Mailing List
    •  A list of e-mail addresses identified by a single name, such as hanna@yahoo.com. 
    • Most e-mail clients support mailing lists, which enablesto broadcast e-mail messages to groups that has define.
    3. Usenet newsgroup & forum
    • Newsgroups are technically distinct from, but functionally similar to, discussion forums on the World Wide Web. Newsreader software is used to read newsgroups.
      
    OSI Certified OOS Licenses
    1. GNU Lesser General Public License
    • Free software license published by the Free Software Foundation (FSF).
    • It was designed as a compromise between the strong-copyleft GNU General Public License or GPL and permissive licenses such as the BSD licenses and the MIT License.
    2. Berkeley Software Distribution (BSD)
    • UNIX operating system derivative developed and distributed by the Computer  Systems Research Group (CSRG) of the University of California, Berkeley
     3. MIT License
    • Free software license originating at the Massachusetts Institute of Technology (MIT), used by the MIT X Consortium.
    4. Mozilla Public License (MPL)
     
    • Free and open source software license. 
    •  The MPL is characterized as a hybridization of the modified BSD license and GNU General Public License.