Friday, January 16, 2009

File System Access in Ubuntu

Various file systems can be accessed easily on Ubuntu. Any additional internal hard drive partitions on your system—both Linux and Windows NTFS—will be automatically detected and can be automatically mounted, providing immediate and direct access from your desktop. In addition, you can access remote Windows shared folders and make your own shared folders accessible.

Access Linux File Systems on Internal Drives
Other Linux file systems on internal hard drives will be detect by Ubuntu automatically. Icons for these systems will be displayed on the Computer window (choose Places Computer). Initially, they will not be mounted. You will first have to validate your authorization before you can mount a disk. To mount a file system for the first time, double-click its icon. A PolicyKit authorization window will appear. You then enter your user password. The option to Remember Authorization is checked, keeping the authorization indefinitely. Whenever you start up your system again, the file system will be mounted for you automatically.

Once your file system is mounted, it displays its icon both in the Computer window and on the desktop. The file system will be mounted under the /media directory in a folder named with the name of the file system label, or, if unlabeled, with the device name such as sda3 for the third partition on the first SATA drive.

Once granted, authentication access will remain in place for a limited time, allowing you to mount other file systems without having to re-enter your password. These file systems will then be automatically mounted as well, provided the Remember Authorization remains checked in the Authenticate window.

Any user with administrative access on the primary console is authorized to mount file systems. You can use PolicyKit agent to expand or restrict this level of authorization, as well as enable access for specific users. In addition, your partitions will automatically be displayed on the desktop and in the Computer window as disk icons.

Access for Local Windows NTFS File Systems
If you have installed Ubuntu on a dual-boot system with Windows XP, NT, or 2000, or you otherwise need access to NTFS partitions, Linux NTFS support is installed automatically. Your NTFS partitions are mounted using Filesystem in Userspace (FUSE). The same authentication control used for Linux file systems applies to NTFS file systems. Icons for the NTFS partitions will be displayed in the Computer window.

The first time you access the file system, you may be asked to provide authorization. The NTFS is then mounted with icons displayed in the Computer widow and on the desktop. Whenever you start up your system, they will be automatically mounted for you. The partitions will be mounted under the /media directory with their labels used as folder names. If they have no labels, then they are given the name disk, and then numbered as disk0, disk1, and so on for additional partitions (unlabeled removable devices may also share these names). The NTFS partitions are mounted using ntfs-3g drivers.

Access to Local Network Windows NTFS File Systems
Shared Windows folders and printers on any of the computers connected to your local network are automatically accessible from your Ubuntu desktop. The DNS discovery service (Ahavi) automatically detects hosts on your home or local network, and will let you access directly any of the their shared folders.

To access the shared folders, select Network from the Places menu to open the Network Places window. Your connected computers will be listed. If you know the name of the Windows computer you want to access, just click on its icon, otherwise, click on the Windows network icon to see just the Windows machines. However, local systems cannot access your shared folders until you install a sharing server, Samba for Windows systems, and NFS for Linux/Unix systems. Should you attempt to share a directory, an error notice will be displayed asking you to install Samba or NFS.

Shared Folders for Your Network and Windows: NFS and Samba
To share a folder on your local network, right-click on it and select Sharing options. This opens a window where you can allow sharing, and whether to permit modifying, adding, or deleting files in the folder. You can also allow access to anyone who does not have an account on your system (guest).

To allow others to access your folders be sure the sharing servers are installed, Samba for Windows systems and NFS for Linux/Unix systems. The serves will be automatically configured for you and run. You will not be able to share folders until these servers are installed. This sharing feature is enabled using nautilus-share, and is meant to be used instead of the older GNOME admin-shares. You can still use admin-shares by entering admin-shares in a terminal window, and then clicking the Unlock button to gain administrative access To share folders (directories) with other Linux systems on your network, you use the NFS service (nfs-kernelserver). For Windows systems you use the Samba service (samba).

Source of Information : McGraw Hill Ubuntu The Complete Reference

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