File System

·         Also referred to as simply a file system or filesystem.

·         The system that an operating system or program uses to organize and keep track of files.

·         For example, a hierarchical file system is one that uses directories to organize files into a tree structure. 

·         Although the operating system provides its own file management system, you can buy separate file management systems.

·         These systems interact smoothly with the operating system but provide more features, such as improved backup procedures and stricter file protection. 

·         Also referred to as simply a file system or filesystem.

·         The system that anoperating system or program uses to organize and keep track of files.

·         For example, a hierarchical file system is one that uses directories to organize files into a tree structure.

      

       File sharing

·         Is the practice of distributing or providing access to digitally stored information, such as computer programs, multi-media (audio, video), documents, or electronic books.

·         It may be implemented through a variety of ways. Storage, transmission, and distribution models are common methods of file sharing incorporate manual sharing using removable media, centralized computer file server installations on computer networks, World Wide Web-based hyperlinkeddocuments, and the use of distributed peer-to-peer networking (see peer-to-peer file sharing)

·         Sharing of files on multi-user systems is desirable.

·         Sharing may be done through a protection scheme.

·         On distributed systems, files may be shared across a network.

·         Network File System (NFS) is a common distributed file-sharing method.

        Peer-to-peer file sharing

·         Users can use software that connects in to a peer-to-peer network to search for shared files on the computers of other users (i.e. peers) connected to the network.

·         Files of interest can then be downloaded directly from other users on the network.

·         Typically, large files are broken down into smaller chunks, which may be obtained from multiple peers and then reassembled by the downloader.

·         This is done while the peer is simultaneously uploading the chunks it already has to other peers.

         File Map

·         File mapping is the association of a file's contents with a portion of the virtual address space of a process.

·         The system creates a file mapping object (also known as a section object) to maintain this association.

·         A file view is the portion of virtual address space that a process uses to access the file's contents. 

·         File mapping allows the process to use both random input and output (I/O) and sequential I/O.

·         It also allows the process to work efficiently with a large data file, such as a database, without having to map the whole file into memory.

·         Multiple processes can also use memory-mapped files to share data.

·         Processes read from and write to the file view using pointers, just as they would with dynamically allocated memory.

·         The use of file mapping improves efficiency because the file resides on disk, but the file view resides in memory.

·         Processes can also manipulate the file view with the VirtualProtect function.