Operating system (DOS) - a set of programs that control the operation of a PC;
File - a set of interrelated data with a common name located on a floppy disk or hard drive and available for processing on a computer;
The file name is used to refer to the file. FILE NAME: name.type
name - can contain Latin letters, numbers and underscores, no more than 8 characters;
type - can contain Latin letters, numbers and underscores, no more than 3 characters. The type or extension may be missing.
docum1.txt lex.bat baza
Driver - a program that controls external devices;
kbr.sys - keyboard driver
Folder (directory, directory) - a group of files, united by some attribute.
For convenient access to files, directories are used. A directory can contain files and other directories. Thus, directories form a tree.
Directory names can be the same as file names, and also:
Current directory;
Parent directory;
\\ - root directory.
Directory names are terminated with \\ (backslash).
To refer to a file that is not in the current directory, the full (path) file name is used.
Full file name: drive name route file name
d: \\ users \\ fox \\ fhg.fox
Filename patterns
To work with a group of files (copy, delete, etc.), file name templates are used.
* any number of any characters
Any character but one
Table - Sample templates
Standard file types:
* .bat - batch files
* .exe - boot files
* .com - boot files
Other files:
* .txt - text files
* .doc - text files
* .dbf - database file
* .sys - system files
* .bak - safety file
All MS DOS commands can be divided into internal and external. Internal commands are supported by the MS DOS kernel (command.com) and can always be executed. External commands are executed only if there is a program file on the disk that executes this command. Any program can be considered as an external command.
Login to Windows
Each time you start Windows, the Windows logon dialog box is displayed. When you log on to Windows, your computer recognizes you as a system user. In addition to security purposes, this procedure allows Windows to store personal settings, such as recently used documents, favorites, and desktop decoration. Password entry is also required.
Figure 2.1.- Windows Login Dialog Box
If your computer is connected to a network, you may also need to enter a domain name and password to log on to the network. This dialog box appears immediately after the previous one and has the same appearance. If you do not know the domain name or password, ask your network administrator.
Logging into Windows for the first time
In the dialog box Welcome to Windowsenter your username and password, and then click OK.
The entered password is displayed on the screen as asterisks (*). If a password is not required, this field should be left blank and click the button OK.
In the window Setting Windows passwordre-enter your password in the field password confirmationand then click OK.
The Windows desktop will be displayed. Installation is complete and you can start using Windows.
Note.You can also open the "Welcome to Windows" window by clicking the "Start" button and then successively selecting "Programs", "Accessories", "System Tools", "Welcome to Windows".
Mouse operation
The mouse is a hand-held pointing device, so called because it allows you to control the mouse pointer on the monitor screen. It is designed to perform tasks on a computer.
When you move the mouse across the table, the mouse pointer moves on the screen. To perform any actions on an object, place the pointer over the object and press the mouse button once or twice (“click” or “double-click” the object). For example, a double-click is usually used to open and work with files, files are “dragged” with the mouse button down to move files from one location to another, and a single click is used to select files. In fact, almost all actions can be performed with the mouse. The mouse pointer usually looks like an arrow, but it can be different.
A) the MS-DOS boot program, checks that the first 2 files are not found in the root directory of the disk boot, an error message is displayed.
B) the loader program reads the beginning of the IO.SYS file and the MS-DOS.SYS file into memory.
C) if there is a compressed disk driver file DBLSPACE.BIN or DRVSPACE.BIN in the root directory, then MS-DOS loads this driver.
D) the CONFIG.SYS file is read and in accordance with it the device drivers are loaded and the OS parameters are set.
E) the command processor COMMAND.COM is read from the root directory of the boot disk and control is transferred to it.
F) COMAND.COM executes the AUTOEXEC.BAT batch file, if AUTOEXEC.BAT is not found, then MS-DOS asks the user for the current date and time.
G) after executing the AUTOEXEC.BAT file, a DOS prompt is displayed, for example C: \\\u003e.
MS-DOS commands for working with directories.
A directory is an area on disk where file attributes are stored.
A) creation:
Md<имя каталога>
B) moving and renaming:
Move<имя к. исх>_<имя к. рез.>
C) deletion:
Rd<имя к.> in some DOS versions, rd removes an empty directory.
Deltree<имя к.>(external team)
D) moving:
Cd<имя к.>
C: \\ work \\\u003e cd ..
Cd \\ from present to root c: \\
E) dir-view the contents of the current directory.
MS-DOS commands for working with files.
A) creation - copy_con_<имя файла> c: \\ _ this opens an area where you can write content. To save the created file - F6 or ctrl + Z
B) renaming - ren<имя файла(исходного)>_<новое имя ф.>
B) move - move<исходное и.ф.>_<(результат)и.ф.>
Move c: \\ cstudent \\ ali.txt_c: \\ work \\ ali.txt
D) deletion - del<и.ф.>
D) copying - copy<и.ф.1>_<и.ф.2>
E) opening a file
1) copy<и.ф.>_con
2) type<и.ф.>
G) editing - edit<и.ф.> this opens the built-in text editor and displays the contents of your file.
File concept. File names. Patterns used in filenames.
A file is a named area on a disk or other storage medium.
Files are often divided into 2 categories:
1) text
2) binary
The executable file is the main file of the program that launches it for execution. They have a com or exe extension.
Document files - data corresponding to one document (text, graphic editors are created).
File names.
Files designation consists of 2 parts: name and extension. The name can contain from 1 to 8 characters. Expansion starts with a dot, followed by 1 to 3 characters.
For example:
Name extension
Patterns in the file name. You can use * and? to specify a group of files from one directory.
The * symbol - denotes any number of any characters in the file name or extension.
Symbol? - denotes a single derived character or the absence of a character in a file name or extension.
File system concept.
Working on a personal computer in the operating system environment is actually reduced to working with files. Files are created, written to disk, stored and read from it, printed out on a printer, sent over information networks, etc.
File Systemis a specially organized structure for storing and accessing data of any type. To implement a file system, service (management) information is required, including a File Allocation Table (FAT).
The file system has three main functions:
· Determination of the physical location of files and directories on the disk;
· Access to files and directories on disk;
· Determination of occupied and free disk space.
Any disk drive must be formatted before using it.
Formatting is the process of writing to a disk special control information that defines the start and end points of individual disk sectors.
Information on any magnetic disk is recorded along concentric circles - tracks. Tracks are numbered sequentially from the farthest from the center (zero) to the nearest. Their number depends on the type of disc.
The tracks on all sides of the disc, located on circles with the same radius, are united under the general name of a cylinder. For example, on a floppy disk, a cylinder is always composed of two tracks: track 0 on side 0 and track 0 on side 1.
Tracks, in turn, are divided into sectors - the minimum amount of information that can be processed by the operating system (the standard sector length is 512 bytes). There are gaps between the sectors. On each disc, all tracks contain the same number of sectors, which depends on the disc type.
Each sector has its own address, which is located in its header. For example, there are 720 sectors on a 360 KB floppy disk, which are numbered from 0 to 719. There are two options for addressing sectors:
· Absolute when specifying detailed sector coordinates, for example, side 0, cylinder 3, sector 1;
· Ordinal, when the end-to-end sector number is indicated, for example, sector 29.
The number of tracks, sectors and sector size depends on the device and media types and how it is formatted. In the process of formatting, service information is applied to the disk, dividing its entire surface into sectors (512 bytes in size). However, the smallest unit that the file system can allocate for files and directories is usually multiple sectors and is called a cluster. Therefore, it can be argued that any disk consists of clusters, each of which, in turn, consists of one or more sectors.
Various operating systems use corresponding file systems, some of which can only recognize one file system, while others can handle several. There are five main file systems.
1. FAT is used by DOS and Windows 95 / NT operating systems (can also be used in any later versions of Windows 98/2000 / ME / XP / 2003 / Vista). The file system uses a 16-bit file allocation table (hence sometimes called FAT16), which allows for a maximum of 65535 (216 - 1) clusters, and supports disks up to 2047 MB. Regardless of the size of the hard disk, the number of sectors in one cluster must be such that the total available space can contain up to 65535 clusters. Therefore, the more space available, the larger the cluster size will be. The relationship between cluster size and disk size when using the FAT file system is shown in the table.
If you need to use a disk larger than 2 GB, you should partition it into logical disks. This is sometimes done to optimize the storage of information on the hard drive.
2. FAT32 used by Windows 98/2000 / ME / XP / 2003 / Vista operating systems (DOS and Windows 95 / NT cannot work with it). The file system uses a 32-bit file allocation table to accommodate over 4 billion (232 - 1) clusters and supports large disks up to 127 TB. FAT32 has dual boot blocks, uses smaller clusters than the FAT file system, and supports any size root directory. The relationship between cluster size and logical disk size when using the FAT32 file system is shown in the table.
The larger the cluster, the lower the disk utilization efficiency. Using FAT32 reduces cluster size and improves disk space utilization on small disks.
3. NTFS (New Technology File System - new technology file system) created specifically for Windows NT and supported by Windows NT / 2000 / XP / 2003 / Vista. The file system uses a lot of space for system structures, so it is not recommended to use it on small disks (less than 400 MB). NTFS is based on the Master File Table (MFT), the critical (most important) part of which is stored in multiple copies, which protects against data loss and corruption. The cluster size does not depend on the disk size and is 512 bytes. Using small clusters reduces wasted disk space. In addition, NTFS is able to automatically find and remove from use bad sectors of the hard disk.
4. Linux Ext2 designed for the free Linux user operating system (from the Unix family). The file system supports a maximum disk size of up to 4 TB. Linux Ext2 reduces the time it takes to recover the file system after a crash, which is important when using multi-user disk arrays.
5. UDF (UniversalDisk Format - universal disk format) is a universal file system that allows you to store a variety of information on one medium: audio recordings, videos, photographs and data files. This ensures cross-platform compatibility, that is, a disk with such a file system becomes a single medium for DOS / Windows, Macintosh, OS / 2 and Unix. In 2000, the file system was adopted on its basis MicroUDFadapted for use in DVD.
All of these file systems are used in different cases within the respective operating systems, while sometimes it is possible to choose one or another file system, for example FAT32 or NTFS in Windows XP.
File concept. Filename pattern.
File (file) is a named area on a disk or other machine medium in which certain information is stored (although in some cases data may be missing, then there will be a "null" file). Files can store various information: texts, tables, figures, drawings, etc.
The file does not require contiguous space for its placement and usually occupies free clusters in different parts of the disk. The smallest file occupies one cluster (even if it is zero), large files can be located in a significant number of clusters. Information about the numbers of these clusters is stored in a special file allocation table.
Any file is characterized by four parameters:
1. Full file name, consisting of two parts, separated by a period ".":
· The file name is formed of no more than eight characters, and only numbers, Latin letters, hyphen "-" and underscore "_" are used;
· File type (extension) is formed from no more than three characters, and the same characters are used as in file names. The file extension is used to characterize the information stored in it. A number of standard file types are installed in the DOS operating system: .arj - archive file, .bak - file copy, .bat - command file, .com - system command file, .exe executable file, .hlp - help file, .txt - text file, .doc - Word document, .xls - Excel document, etc.
The operating system cannot contain files with the same fully qualified names at the same time (although files can have the same names or extensions).
2. File size in bytes (large files are measured in kilobytes, megabytes, or gigabytes).
3. File creation date and time (may be the same for different files).
4. Special file attributes: R (Read only) - read only, Н (Hidden) - hidden file, S (System) - system file, A (Archive) - file that has not been archived.
Often a situation arises when there are files on the computer, but the user does not have full access to them, for example, he can only read files with the R attribute, but cannot change them. Or some of the files (with R or S attributes) are simply hidden by the operating system from the user. Moreover, the "system" attribute is set by the OS to files only on its own, and the "hidden" attribute can be assigned to a file manually (as well as the "read-only" attribute).
You can perform various operations with files, for example: Search, copy, move or delete files. Operations on a group of files are easy to perform using a template when creating a group. File name pattern is a special form that uses the asterisk "*" or the question "?" in the file name and file type fields.
The "*" symbol means any number (from 1 to 8) of any valid characters. A single asterisk "*" can be used to denote any name or type of file. For example, the web. * means a group of files named web and any extensions (web.exe, web.l, etc.); pattern *. * means all files of any name and type (web.exe, a.b, win.bak, etc.).
The "?" means the presence or absence of one valid character. A few questions "?" can be used to denote multiple characters in a file name or type. For example, the pattern web ?, txt means a group of files with the extension. txt, the name of which consists of three or four characters, and the fourth character can be any (web.txt, web2.txt, weba.txt, etc.).
The length (size) of the file is determined in bytes and changes if it is edited.
Normal.
File name
File system organization
All modern disk operating systems provide the creation of a file system designed to store data on disks and provide access to them. The organization of the file system depends on the operating system. The most common type is tabular.
The logical name of the floppy drive is A:
The logical name of the hard drive is C :. If the hard disk is divided into several logical partitions, then each of them is named with the letters of the English alphabet: C :, D :, E :, F :, etc.
The logical drive name of the laser disk is the last letter in the list of logical drive names for this computer.
File -it is a named sequence of bytes of arbitrary length .
Each file on the disk has a designation that consists of 2 parts: name and extension, which are separated by a dot. The length of names is limited by the 255.0 / 0.255 scheme (no more than 255 characters in total for the file name and name extension). It is allowed to use Latin and Cyrillic characters in the file name, numbers and special keyboard characters, with the exception of the following characters: * : " ? < > \ / | .. The extension is optional and is mainly used to describe the contents of the file. files with the extension: .txt, .doc, .rtf - text; .bmp, wmf, .ico are graphic and ..com, .exe, .bat are executable programs.
VAK - a copy of a previously created file;
. $$$ is a temporary file automatically created by any program itself.
In addition to the name, the file has a number characteristics:- file attributes;
File creation date;
File creation and editing time;
Length (volume) of the file.
Attributesfile indicate the nature of its use and the ability to access
Read-Only- a file used for reading only; most often he cannot
be destroyed or edited, but copying and operations are allowed
Archive- archived, created when the file is changed and stored in the archive
file system;
Hidden- hidden file;
System- systemic.
If the file is not assigned any of the listed attributes, then it is called
Creation date and creation timerecorded at the time of creation and modification of the file by
pC system clock.
It is useful to use name patterns to find files. Like the file name, the name template consists of 2 parts separated by a period. When specifying a template, wild symbols (metacharacters) * and? Are used. Moreover:
* - replaces any number of any;
? - replaces one arbitrary character.
For example:
* .doc - template for files with the .doc extension;
t * .xls - template for files whose name begins with a letter t, and extension .xls;
All files on disks are located in directories or folders.
Folder(to atalog, directory) - a special file containing information about ordinary files, grouped into a single list by one or another criterion, either by the user himself (for example, memos, outgoing letters, methodological developments, favorite game programs, etc.), or by software developers ( a set of files that make up a single software package). Such combining of files is performed, as a rule, in order to facilitate the search for information on the computer, as well as for the convenience of group (simultaneous) processing of ordinary files and folders. The folder (directory, directory), in addition to the list of files included in it, also contains system information regarding the characteristics (attributes) of these files.
On every medium there is main or root directory where all other directories are located, called subdirectories and some files. Thus, a hierarchical structure is created. The directory the user is currently working with is called current ... Inside a folder (directory, directory), there can be both regular files and subfolders, which in turn can contain folders of the next nesting level. In this way, a hierarchical system of nested folders and files is implemented.
To organize access to a file in many operating systems, the same method is used, consisting in the formation of a character string - access paths, which contains information about the location of the file on the VC (for example, C: \\ Program Files \\ Microsoft Office \\ Office \\ Samples \\ Products.doc). The number of files or folders in the root and non-root directories is unlimited! The total number of characters in the file path is no more than 260.
Cylinder concept
First, the disc is represented as a collection of surfaces. Floppy disks have only two of them (upper and lower), but hard disks are actually "stacks" consisting of several platters, so they have more surfaces.
Secondly, each disk surface is divided into circular tracks, and each track into sectors. The sector sizes are fixed at 512 bytes.
To find a particular file on the disk, you need to know where it is located, that is, you need its address. The easiest way would be to write the file address in the form of surface number, track number and sector number, but in reality this is not done exactly like that. The fact is that each surface has its own read / write head, and these heads do not move separately, but simultaneously. That is, if, for example, the fifth head is brought to the thirtieth track, then all the heads are brought to their thirtieth tracks. Therefore, instead of the concept of a track, the concept is used cylinder. Cylinder - it is a collection of all tracks having the same numbers, that is, equidistant from the axis of rotation. Therefore, the actual location of the file on the hard disk is determined by the cylinder number, surface number and sector number.
Cluster concept . A sector is the smallest unit of data storage, but not all file systems use it for addressing. It is too small for that. Operating systems such as MS-DOS, Windows, OS / 2 use a larger storage unit for addressing, called cluster . A cluster is a group of adjacent sectors. The cluster size depends on the size of the hard disk. The larger the disk, the larger the cluster size is assigned. Typical values \u200b\u200bare 8,16,32 or 64 sectors.
The data on which disk cluster a particular file starts in is stored in the system area of \u200b\u200bthe disk in special file allocation tables(FAT tables). Since the violation FAT-table leads to the inability to use the data recorded on the disk, special reliability requirements are imposed on it, and it exists in two copies, the identity of which is regularly controlled by the operating system.
Currently, Windows 98, Windows 2000 and Windows Millenium operating systems provide a more advanced file system - FAT32with 32-bit fields in the file allocation table. This allows you to work with any modern hard drives.
Files and directories are the most important objects in the file system. It is necessary for the OS to be able to work with data on the hard drive.
