Question

i need to know about boot loader and kernel in deep from its basic.
i search the google and got a lot of links… but i need to find the good ones. if you pals have any docs or video or htmls share with me…..

thanks in advance

Answer 1

Kernel is the core code component of the operating system. It is used to interact with the hardware and provides an interface for application software. Read wikipedia here for detailed info.

Details vary from platform to platform, but in general the following steps
represent the boot process.

• When the computer starts, the BIOS
  performs Power-On-Self-Test (POST)
  and initial device discovery and
  initialization, since the OS’ boot
  process may rely on access to disks,
  screens, keyboards, etc.
• Next, the first sector of the boot
  disk, the MBR (Master Boot Record) is
  read into a fixed memory location and
  executed. This sector contains a
  small (512-byte) program that loads a
  standalone program called boot from
  the boot device, usually an IDE or
  SCSI disk.
• The boot program first copies itself
  to a fixed high memory address to
  free up low memory for the operating
  system. Once moved, boot reads the root
  directory of the boot device.

• To do this, it must understand the
  file system and directory format,
  which is the case with some
  bootloaders such as GRUB
  BootloaderGRandUnified.

• Other popular bootloaders, such as
  Intel’s LILO, do not rely on any
  specific filesystem. Instead, they
  need a block map, and low-level
  addresses, which describe physical
  sectors, heads, and cylinders, to
  find the relevant sectors to be
  loaded.

• Then it reads in the operating system
  kernel and jumps to it. At this
  point, boot has finished its job and
  the kernel is running.