Owlcom software
basadOwlCom  Software
Let's Owl manage your files
Welcome Screenshots Buy now Download Write to Owl Subscribe to news FAQ Links
Graf, describing the hierarchy of folders can be wood or network. Catalogs are trees, if a file is allowed to enter only in the same directory (see Figure 7.3, b), and network - if the file can include just a few folders (Figure 7.3 in). For example, MS-DOS and Windows directories form a tree-like structure and UNIX-network. In the tree structure of each file is a sheet. Catalog highest level is called the root directory, or root (root). When an organization exempt from the user remember the names of all files, it is about to submit, which group can be assigned a file to by the consistent view directories to locate him. Hierarchical structure suitable for multiplayer work: each user with their files located in a directory or directories poddereve, but all the files in the system logically linked. Private case hierarchy is a single organization, which includes all the files in one folder (see Figure 7.3, a). Filenames All types of files are symbolic names. In organized hierarchical file systems are usually used three types of name-files: simple, and relative components. A simple, or short, symbolic name identifies the file in a single directory. Simple names assign files users and programmers, but they must take into account the limitations OS as a range of characters, and character name. Until relatively recently, these borders were very narrow. For example, the popular file system FAT length names restricted scheme 8.3 (8 characters proper name, 3-character extension name), and the file system s5 supported many versions of UNIX OS, the mere symbolic name could not contain more than 14 characters. However, the user is much easier to work with long names, as they provide a simple name files easily, clearly pointing that is contained in the file. So modern file systems, as well as enhanced versions of existing file systems are usually simple symbolic support for long file names. For example, the file sie- topic NTFS and FAT32 members of the Windows NT operating system, the file name can contain up to 255 characters. Examples of simple file names and directories: quest_ul.doc task-entran.exe annex 254L SS at the Russian yazyke.doc installable filesystem manager.doc In hierarchical file systems different files allowed to have the same simple symbolic names on the condition that they belong to different directories. So here is a scheme of "one simple file-name". For odpoznachnoy identification file in the system used by so-called full name. The full name is a simple conversation character names of all directories crossing path from the root to the file. Thus, the full name is a composite, which are simple names separated by separator in the OS. Often used as a separator or back straight away, with no state name root. Fig. 7.3, a two files are simple main.exe name, but their constituent names / depart / main. ehe and / user / anna / main.exe different. In between tree file system and file its full name is mutually clear line "one file, one full name." In the file systems of the network structure, the file may consist of multiple directories, and therefore have several full names; Here true that "one file, many proper names." In both cases, file clearly identifies full name. The file may be identified relative to the name. The relative file name is determined by the notion of "current directory." For each user every time one of the catalog file system is ongoing, and this directory is selected by the user teammates OS. File system captures the current directory name, then use it as a complement to the relative names for the full file name of education. Using relative names user identifies the file names chain catalogues crossing route from the current directory to the file. For example, if the current directory is the directory / user, the relative file name / user / anna / main.exe as follows: anna / main.exe. Some operating systems are allowed to give the same file some simple names, which can be interpreted as an alias. In this case, as in a network structure, "a line single file, many proper names, because each simple filename with at least one full name. While full name clearly identifies the file, the operating system easier to work with the file if the files and their names are mutually clear line. To this end, it shall file a unique name, so that the ratio of true "one file, one unique name." Unique name coexists with one or more character names assigned to the file by users or applications. The unique name is a numeric identifier, and is for the operating system. An example of such a unique filename is the descriptor index number UNIX. Mounting Generally, a computer system can have multiple disk devices. Even a typical personal computer usually has a hard disk drive, a floppy disk drive in and drive to the CD. Powerful same computers are usually equipped with a large number of disk drives that are installed packages discs. Indeed, even one physical device through the operating system can be presented in several logical devices, in particular by disk space split into sections. The question is how to store files in the system with few external memory devices? The first is that in each of the devices running standalone file system, the files that are on the same device, describes the tree of directories is not connected with the trees of directories on other devices. In this case a unique identification file for the user, along with a symbolic name of the file to indicate the logical identifier devices. An example of such an autonomous existence file system is MS-DOS operating system, which includes the full file name ID logical drive letter. Thus, when the file located on the A drive, the user must specify the name of the disk: A: \ privat \ letter \ uni \ let1.doc1. 1 In practice, increasingly used the relative form of naming, which does not include the name of the drive and chain have top-level directories specified default. Another option is the organization file storage, in which the user can combine file systems located on different devices in a single file system, described a single directory tree. The operation is called moptirovaniem. Consider how the operation in the case of UNIX OS. Among all available in the logical disk devices operating system provides a device called a system. May has two file systems located on different logical drives (Figure 7.4), with one disk is a system. File system, based on a system disk, a root. To contact hierarchies files in the root file system chosen some existing directory, in this example, the directory man. After mount folder man becomes chrooted second file system. Through this directory is mounted file system as a subfolder connected to a common tree (Figure 7.5). After mounting a common file system for the user no logical difference between root and mounted file systems, in particular the naming of files is the same as if it were from the very beginning was united.
Welcome    Screenshots    Download    Buy now Write to Owl    Subscribe to Owl news   FAQ   Links  
Copyright 2004-2011 OwlCom Software .

Owl Commander

OISV - Organization of Independent Software Vendors - Contributing Member Software Submit .NET - FREE and PREMIUM search engines submission and software submission and software promotion service. Owl Commander

Valid HTML 4.01 Transitional