MBR and Filesystem Structure

MBR

MBR (Master Boot Record) is Table of Boot sector in storage that is place for record any boot loader of operating system, when unit computer installed into hardisk.

MBR is domain of identity or first place run in hardisk cause that place at Cylinder 0, Head 0, Sector 1 in hardisk, place for check all of hardware in unit of computer. 

The Master Boot Record contains the Partition Table for the disk and a small amount of executable code. On x86-based computers, the executable code examines the Partition Table, and identifies the system partition. The Master Boot Record then finds the system partition's starting location on the disk, and loads an copy of its Partition Boot Sector into memory. The Master Boot Record then transfers execution to executable code in the Partition Boot Sector.

• The master boot routine that is run when the computer is started
• The partition table that contains the information about the partitions
• The MBR identification code that identifies the MBR as a master boot record

File System

File systems organize and manage hard disk space. They enable you to create folders and files and to find them again. They are also used to grant or to block access to files. Windows file systems do not operate directly with sectors. They work with clusters. A cluster groups multiple sectors into a single data storage unit for ease of management. Clusters also specify how much hard disk space is allocated to each file. Each file requires a whole cluster, even if it does not use all the available space. 


FAT 16

FAT16 is one of several file system format in storage, in hardisk FAT16 partition have specification size of cluster every value of size of partition like this table

Lack of FAT16

Lack of storage space. No additional programs or files, especially for those who use the system with Windows95 and have more than 512MB of hard disk.

Ineffective. Large cluster size leads to waste, Not efficient in the arrangement of files and asks the user often do Defrag to get the previous cluster completely unused.

The maximum size disk that can be supported in a single hard disk FAT16 is 2GB.

That lackness is revision by FAT32 filesystem 
  
FAT 32

FAT32 is development of FAT16, several file system have structure in media storage or disk like this table

FAT32 is a file system for Windows. It is a development of the File Allocation Table (FAT) file system that Microsoft created to support large drives in a single volume. The File Allocation Table made things easier on the user by allowing them to see only a single drive letter, instead of many different letters. Disc space is also used more proficiently with this system.

FAT32 increases the number of bits which can be used to address hardware sectors. Hardware sectors are often referred to as clusters. Clusters are identified with a larger number of bits with each development of the FAT file system.

Excellence of FAT32

Using 32 bits to represent the cluster

FAT32 provides a larger drive sizes. Sizes are provided up to 2 terabytes, compared with only 2GB of FAT 16.

FAT32 uses a more efficient place. FAT32 uses smaller cluster sizes (4KB cluster size of the drive for 8 GB), more efficient 10 - 15 percent compared to FAT or FAT16. The minimum size for the FAT32 partition of about 260 MB.

Lack of FAT32

Microsoft will support the FAT32 file system's functional errors in reading independently and store the files either in the form of real (real mode) and the form of protected (protected mode). Microsoft support facilities including real and protected mode on Windows 95.

Although the FAT32 file system supports disk sizes up to 2 terabytes (TB), some hard disks may not be able to fill the partition that can be turned on is larger than 7.8 gigabytes (GB) due to limitations of the system I / O base (BIOS) INT 13 interface

 


NTFS

The weakness of the FAT is the inability to control access to files or folders from the hard drive, allowing outsiders to change the data in a network system.

NTFS is type of filesystem is designed for 2 to the 64th power of clusters. These file systems allow for significantly larger partitions. They also make better use of data storage.

This type have diferent structure with FAT this is explaination of diference of them

The unnamed stream is a mandatory element and is always present. If you are creating an alternate atream and the file does not exists, the system will automatically create a zero length unnamed stream. If you are deleting the unnamed stream, the system considers it as a request to delete the whole file, and all the alternate streams will also be deleted.

The security descriptor and the file attributes belong to the file as a whole, not to the unnamed stream. For instance, no stream can be opened for writing if the read only attribute is set.

NTFS currently has 16 metafiles, which I’ll describe later on. Finally, each File
Record is composed mainly of Attributes. Attributes are clearly defined (more
on them later), and each one of them is a structure that describes the object
in the File Record.

EXT2

Ext2 was first developed and integrated in the Linux kernel, and is now also being developed for use on other operating systems.

The goal is to create a powerful file system, which can implement those files from UNIX semantics, and has an advanced service features.

Ext2 was first developed and integrated in the Linux kernel, and is now also being developed for use on other operating systems.

The goal is to create a powerful file system, which can implement those files from UNIX semantics, and has an advanced service features.

Capability

1. Ext2 file system capable of supporting multiple file types from UNIX standard, such as regular files, directories, device special files and symbolic links.
2. Ext2 able to manage system files are created in a large partition.
3. Ext2 file system capable of generating file names are long. Maximum of 255 characters.
4. Ext2 require several blocks to super user (root).

EXT3

EXT3 is a journalled filesystem

Journalled filesystem is designed to help protect data in it.

With a journalled filesystem, then we no longer need to check the consistency of data, which will take very long for my disk.

EXT3 is a filesystem that was developed for use on the Linux operating system.

EXT3 is the result of improvements in the form of EXT2 EXT2 better by adding a variety of advantages.

Structure 


bootstrap
code to be loaded into memory and executed when the computer is powered on. MVS volumes reserve the entire first track of the first cylinder for the boot strap.

volume descriptor
information describing the size, type, and layout of the file system and in particular how to find the other key meta-data descriptors

file descriptors
information that describes a file (ownership, protection, time of last update, etc.) and points where the actual data is stored on the disk.

free space descriptors
lists of blocks of (currently) unused space that can be allocated to files.

file name descriptors
data structures that associate user-chosen names with each file.

Excellence
   

Availability:

EXT3 does not support the process of checking the file system, even when the system is not cleaned experienced a "shutdown", except in some very rare hardware errors.

Things like this happen because the data is written or stored into a disk in a way so that the file system is always consistent.

The time required to recover an ext3 file system after the system is not cleaned off is independent of the size of the file system or file number, but
depending on the size of the "journal" used to maintain consistency. Journal of the size of the initial (default) takes about 1 second to recover (depending on hardware darikecepatan).

Data integrity

By using the ext3 file system we can get a stronger assurance of data integrity in the case where the system is not cleaned off (shutdown).

We can choose the type and level of protection of data received. We can choose to keep the file system remains consistent, but still allow the damage to the data in the file system in the case turned off (shutdown) system that has not been cleaned; this could provide an increase in speed in some circumstances.