About System View and User of " OS "

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LINUX

 Understanding users and permissions

     Linux is based on the idea that everyone using a system has their own username and password. Every file belongs to a user and a group, and has a set of given attributes (read, write and executable) for users, groups and all (everybody).

     A file or folder can have permissions that only allows the user it belongs to to read and write to it, allowing the group it belongs to to read it and at the same time all other users can't even read the file.

 System View

   File system is a method of storing and organizing data / files on your computer. File system uses a storage media such as hard drives and CD-ROM.

      There are many file systems  Extended File System in Linux. Of the ext2, ext3, and the newest ext4.

1. Second Extended (Ext2)

      Second Extended File system (Ext2) was designed by Remy Card, as the file system is extensible and powerful for use on the Linux operating system.

2. Third Extended File System (EXT3)

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

3. Fourth Extended File System (Ext4)

      Ext4 was released as a complete and stable starting from kernel 2.6.28 so if your distro

      has a default kernel version tersebuat or on its automated system you already support

      ext4 (with records already in the include into the kernel) but it must use the version of 

      e2fsprogs version 1:41 .5 or more.

WINDOWS

Windows User
    You can log on to the computer as an administrator, as a user, or as a power user. The following list describes more information about the permissions that are granted to each kind 

of user:

 - Administrators have complete and unrestricted access. (Full Control,Read Atributes,Write Atributes, Read, Change, Delete Permissions)

 -  Power users have many administrative powers, but they have some restrictions. 

-  Users have more restrictions than power users, and they have very little authority over the computer. (File modify, Read &execute, Read, Write)

System View

    When Microsoft released Windows 2000, they released a new version of NTFS, which was versioned 5. The new NTFS permissions were essentially the same logical control as the older version that was available in Windows NT, however, there were some radical and essential changes that occurred to control how the permissions were inherited and configured for each file and folder. Since NTFS permissions are available on every file, folder, Registry key, printer, and Active Directory object, it is important to understand the new methods and features that are available once you have Windows 2000, Windows XP, or Windows 2003 Server installed to control resources.

         To perform an undelete under Windows NT on any of the supported file systems. Undelete utilities try to directly access the hardware, which cannot be done under Windows NT. However, if the file was located on a FAT partition, and the system is restarted under MS-DOS, the file can be undeleted. The FAT file system is best for drives and/or partitions under approximately 200 MB, because FAT starts out with very little overhead. 

MAC OS

MAC OS User

  Every file and folder on your Mac has permission rules which decides who gets to access those files. Permissions can be set for three different categories: User, Group and Global.
      Whenever you set new permissions of a file or a folder you have to decide which categories should be affected of this change (R - Read permission, W - Write permission, X - Execute permission) :

     The current User, 

     Every user in the same group as the file (Group)

     or everyone else that's not in the same group as the file (Global).

          In order for you to be able to change permissions of a file or a folder you need to have sufficient permissions yourself. 

System View

     The Mac OS Extended Format (HFS+) is a volume format compatible with Mac OS 8.1 and higher, including Mac OS X. In terms of volume, folder, and file size limits, it is similar to the Macintosh Standard Format (HFS). 

       HFS+ or HFS Plus is a file system developed by Apple Computer Inc. to replace their Hierarchical File System (HFS) as the primary file system used in Macintosh computers (or other systems running Mac OS). It is also one of the formats used by the iPod music player. HFS+ is also referred to as Mac OS Extended Volume Hard Drive Format where its predecessor, HFS, is also referred to as Mac OS Standard. 

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