Introduction
The MS-DOS operating system was developed in 1974 by Microsoft. The first version of MS-DOS 1.0 was released in 1981, simultaneously with the first mass-produced personal computer from IBM. In the future, the OS developed, new versions of it appeared. latest version MS-DOS 6.22.
The operating system performs the following tasks:
1) System resource management
2) Giving the user general control over the computer system
The operating system is stored on disks in the form system files, and after the power is turned on, it is automatically loaded into the computer's memory, where it remains all the time while the computer is in operation.
Topic_ OS MS DOS |
COMPOSITION DOS
DOS consists of the following modules and programs:
1) Basic input-output system (BIOS - Basic
input/output system).
2) Bootstrap block ( BOOT RECORD).
3) Basic system expansion module I/O
(IO.SYS).
4) Interrupt handler(MSDOS.SYS ).
5) command processor ( COMMAND.COM ).
6) data compression module ( DBLSPACE.BIN ).
7) DOS utilities (FORMAT.COM, FDISK.EXE, LABEL.EXE, etc.)
8) Loadable device drivers ( HIMEM.SYS,RAMDRIVE. SYS, etc.)
9) AUTOEXEC.BAT and CONFIG.SYS files.
Topic_ OS MS DOS |
1.1. BIOS
The BIOS has a special place. It can be considered as constituent part hardware on the one hand, it is a DOS software module.
The BIOS performs tests on the main components of the machine after the power is turned on.
The second important function of the BIOS is to call the boot block to load from system disk into the memory of the bootstrap block, and then transfers control to it, which, in turn, loads all the other DOS modules.
Another important function of the BIOS is to service system interrupts. Interrupts are generated by both hardware and software to perform various operations.
1.2. Boot Record Block
The bootstrap block is a small program whose sole purpose is to read two DOS modules, IO.SYS and MSDOS.SYS, into RAM. The boot block itself is always located in the same place - on the 0th side in the 1st sector of track number 00. The length of the Boot Record is 512 bytes, i.e. occupies only one sector.
Topic_ OS MS DOS |
1.3. BIOS Expansion Module (IO.SYS)
The basic input/output system is a part of the OS that is not subject to change. Extending the BIOS with an optional DOS module gives the OS the flexibility to manage a set of additional devices.
This module can be modified to suit the requirements of the OS. Using this module allows you to connect new external devices - drivers.
Drivers allow the system to support new external devices and organize the work of those computer devices in a new way, when the exchange of information with them should occur differently than in the standard version of the OS.
The need to connect external device drivers, as well as changes to other DOS parameters, is notified through the CONFIG.SYS file.
1.4. Interrupt handling module (MSDOS.SYS).
V unlike the IO.SYS module, which works with low-level interrupts,(0h-20h) MSDOS.SYS module deals with high-level interrupts (21h-59h). It forms the top level of the system, with which the vast majority of programs interact. This module ensures the operation of the file system, I / O devices, handles special situations related to program termination and errors. The functions implemented by MSDOS.SYS are used both by the OS itself and by applications.
Topic_ OS MS DOS |
1.5. Command Processor (COMMAND.COM)
Unlike IO.SYS and MSDOS.SYS, the shell can take up any space on the disk and represents a normal program. The main functions of the command processor are as follows:
Reception and processing of commands entered by the user from the keyboard or received from batch file.
Execution of its internal (built-in) commands.
Display of diagnostic and emergency messages, etc.
The shell functions also include executing the AUTOEXEC.BAT file.
The command processor can execute files with the extension .COM, .EXE, .BAT. Files of the .COM type are small programs no larger than 64 KB in size and occupying 1 memory segment. .EXE files are the same programs, but without size restrictions. Files of type .BAT - batch (command) - they contain a set of OS commands.
1.7. Utilities
MS-DOS includes more than 70 utilities designed to perform various functions.
The most commonly used are FORMAT.COM, CHKDSK.EXE, SYS.COM, DISKCOPY.COM, as well as LABEL.EXE, TREE.COM, RESTORE.EXE, PRINT.EXE. In general, any program can play the role of a utility. The main purpose of the utilities is to perform tasks that cannot be included in the shell.
Topic_ OS MS DOS |
1.8. Device drivers
Drivers allow you to expand the functions of standard PC devices or provide control of additional devices. On MS-DOS, the most commonly used drivers are HIMEM.SYS (XMS Memory Extension Management), SMARTDRV.EXE, RAMDRIVE.SYS and ANSI.SYS, etc.
1.9. System configuration files
The CONFIG.SYS and AUTOEXEC.BAT files are designed to create a user-friendly interface. CONFIG.SYS contains DOS configuration directives. They are used to set OS parameters. If this file is missing, system configurations are set to default. In the CONFIG.SYS file
uses DEVICE directives to set additional drivers, LASTDRIVE to determine the number of logical drives, BUFFERS to increase the number of buffers, FILES to set maximum number simultaneously open files and SHELL to specify the location and name of the shell.
The AUTOEXEC.BAT file contains standard DOS commands as well as special batch file commands. This file starts automatically when the OS boots and is intended for auto start programs necessary for the user and (or)
operating system.
Example AUTOEXEC.BAT: @ECHO OFF
SET COMPSEC=D:\DOS\COMMAND.COM PATH D:\DOS
PROMPT $p$g Anti4us
Topic_ OS MS DOS |
2. FILE SYSTEM
file system It is customary to call the organization of storing programs and data on computer disks.
A file is any sequence of data of a certain length that has a name.
The file can store text, program, numeric data, encoded graphic images. The length of files is measured in bytes.
The filename can:
have an extension of no more than 3 characters. Standard extensions:
program text in assembly language |
spare |
||
program text in BASIC |
program text in C language |
||
program |
data file |
||
document, standard WORD file |
program |
||
object |
|||
program text in Pascal |
systemic |
||
temporary |
text, etc. |
||
Note: |
|||
It is forbidden to use device names and reserved DOS names as file names: AUX, CON, PRN, NUL, CLOCK$, COM1, COM2, LPT1, LPT2, LPT3.
Topic_ OS MS DOS |
2.1. Catalogs
In the process of formatting (initializing) a disk, a directory called the root directory is created. The root directory file contains information about the files and directories stored on the disk. Each DOS directory entry is 32 bytes and stores:
- filename (8 bytes)
- name extension (3 bytes)
- file attribute binary code (1 byte)
- reserved field (10 bytes)
- file creation time code (2 bytes)
- number of the first cluster occupied by the file - FAT entry point (2 bytes)
- file size (4 bytes)
A tree-like directory structure is usually used to access hard drive data. The root directory contains subdirectories, which in turn may contain 2nd level subdirectories, etc. Subdirectories are stored in the parent directory as regular files. The difference between a subdirectory and a regular file is that bit 4 of the file attribute byte is set to 1, and the size field is set to 0. The size of a subdirectory is unlimited, which allows you to store any number of files in it. The first and second elements in the “File name” field have the value “.” and ". .”. The element “.” describes the subdirectory itself, while “. .” - parent directory
Topic_ OS MS DOS |
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Operating system MS-DOS Start training All rights reserved Igor Shatalov 2005
Introduction to MS-DOS MS-DOS is a disk-based operating system. A disk operating system is a set of programs that supplement the hardware capabilities of a computer and control the operation of hardware and application programs. The main reason for the need for an operating system is that elementary operations for working with computer devices and managing computer resources are very low level, so the actions that are required by the user and application programs consist of several hundred or thousands of such elementary operations. The operating system hides these complex and unnecessary details from the user and provides him with a convenient interface for work. It also performs various auxiliary actions, such as copying or printing files. The operating system loads all programs into RAM, transfers control to them at the beginning of their work, performs various actions at the request of executing programs, and frees the RAM occupied by programs when they complete. to the plan
Purpose of MS-DOS Management of devices that are part of the computer Management of computer resources (RAM, disk space, etc.) Starts application programs for execution Provides a convenient way for the user and application programs to communicate with computer devices Carries out a dialogue between the user and the computer Go to plan
Composition of MS-DOS The basic input/output system BIOS, located in the permanent memory of the computer. This part of the operating system is "built into" the computer. Its purpose is to perform the simplest and most versatile operating system services associated with I/O. The basic input-output system also contains a test of the functioning of the computer, which checks the operation of the memory and devices of the computer when it is turned on. In addition, the basic input-output system contains a program to call the boot loader of the operating system. The operating system loader is very short program, found in the first sector of every DOS diskette. The function of this program is to read two more operating system modules into memory, which complete the DOS boot process. On a hard disk (hard drive), the operating system loader consists of two parts. This is due to the fact that HDD can be divided into several partitions (logical drives). The first part of the bootloader is in the first hard disk, it chooses from which partition hard drive download should continue. The second part of the bootloader is located in the first sector of this partition, it reads DOS modules into memory and transfers control to them. Disk IO files. SYS and MSDOS. SYS. They are loaded into memory by the operating system loader and remain permanently in the computer's memory. io file. SYS is an addition to the basic I/O system in ROM. The MSDOS.SYS file implements the basic high-level DOS services. The DOS command processor processes commands entered by the user. The command processor is located in the COMMAND disk file. COM on the disk from which the operating system is loaded. to the plan
MS-DOS booting A slight, steady noise from the fan cooling the components is a sign that the computer is starting up after the power is turned on. system block. Next, the bootstrap procedure is divided into three steps. Immediately after turning on the power, a special unit of the built-in basic input / output system (BIOS) starts working, which carries out the procedure for checking (testing) the main hardware components of the computer - the microprocessor, video system, keyboard, disks and random access memory. The results of this test appear on the screen in the form of successive diagnostic messages that do not require any user response. Along the way, you can hear clicks, buzzing, creaking emitted by the equipment being tested. If errors are found at this stage, a corresponding message appears on the screen, sound signal, and this is where the machine ends. If the hardware check is successful, the BIOS reads a small program from disk into memory - the operating system loader or boot block (BNZ). This block is always written to the first sector of any disk in advance, when formatting it, regardless of whether this disk will be used as a system disk or not. The only function of this program is to find two files with the operating system in a certain (known to it) place on the disk, read them into memory and transfer control to them. MS-DOS uses two special-purpose text files, CONFIG, during boot. SYS (configuration) and AUTOEXEC . BAT( automatic execution). These files must be located in the root directory of the drive from which the system boots. At the last stage of loading, the command processor COMMAND is read into memory. com. This processor executes all commands from the AUTOEXEC file. BAT , the last of which is usually a call to Norton Commander . The familiar NC panels and the MS-DOS prompt with a blinking cursor appear on the screen. The system is ready to receive user commands. C:\> _ To plan
MS-DOS Internal and External Commands Some user commands, such as Type , Dir , or Copy, are executed by the shell itself. Such commands are called internal. To execute the remaining (external) user commands, the command processor searches the disks for a program with the appropriate name, and if it finds it, it loads it into memory and transfers control to it. At the end of the program, the command processor removes the program from memory and displays a message about the readiness to execute commands (DOS prompt). External DOS commands are programs that come with the operating system as separate files. These programs perform maintenance activities, such as formatting floppy disks, checking disks, and so on. to the plan
Working with directories and files Changing the current directory is done by typing the name of the drive, then a colon: A: or C: or D:, etc. Change current directory: cd [ drive: ] path Change to root directory: cd\ Change to parent directory: cd.. Forward C:\>A: A:\>D: D:>\ C:\>CD C:WINDOWS \MEDIA C:\>WINDOWS\MEDIA C:\>WINDOWS\MEDIA CD\ C:\> C:\>WINDOWS\MEDIA CD.. C:\>WINDOWS
Working with Directories and Files Directory browsing: dir [ drive: ] [ path\ ] [ filename ] You can use the characters * and ? in the file name. If the file name is not specified, then the entire table of contents of the directory is displayed, otherwise only information about given file or group of files. If no drive or path is specified in the command, the current drive and current directory are assumed. Next C:\Gmouse>dir The volume in device C is labeled MASTER Serial number volumes: 1A12-140D The contents of the C:\Gmouse folder. 11/17/03 02:20 PM 11/17/03 02:20 PM GNETCPL DLL 184 320 10/04/00 05:54 PM GNETSCRL DLL 73 728 10/03/00 05:25 PM GNETMOUS EXE 131 072 10/03/00 05:23 PM SCROLL06. 15:34 SCROLL HLP 25 454 04/06/00 15:34 SCROLL GID 10 843 10/03/00 18:12 UNINST 11/17/03 14:20 README TXT 4 614 10/09/00 15:27 7 files 430 804 bytes 3 folders, 3 785 60 MB free C:\Gmouse>dir /w Volume in device C is labeled MASTER Volume serial number: 1A12-140D Folder content C:\Gmouse [.] [..] GNETCPL.DLL GNETSCRL.DLL GNETMOUS.EXE SCROLL.CNT SCROLL.HLP SCROLL.GID README.TXT 7 files 430,804 bytes 3 folders 3,777.60 MB free C:\Gmouse> The parameter sets the display of the table of contents by screen. The parameter specifies to display only information about the names of files in the directory.
Working with directories and files Create a directory: md [drive: ] [path\ ] directory-name Destroy an empty directory: rd [drive:] [path\ ] directory-name Create text files: copy con file-name press the key (Enter), and after the last - press the key (F6) and then (Enter). View text files: type [ drive: ] [ path\ ] filename Forward C:\>md c:\proba C:\> C:\>rd c:\proba C:\> C:\>copy con primer .txt pervaya stroka vtoraya stroka konec^Z 1 files copied to C:\>type primer.txt pervaya stroka vtoraya stroka konec
Working with directories and files Renaming files: ren [ drive: ] [ path\ ] filename filename The first filename in the command specifies the name of the renamed file, the second specifies the new filename. Deleting files: del [ drive: ] [ path\ ] filename Copying files: copy filename filename copy filename [ directoryname ] If no filename is given in the second parameter, the filenames are not changed during copying. If a filename is given in the second parameter of the command, then it specifies the new name of the copied file. C:\>ren primer.txt tekst.txt C:\>del tekst.txt C:\>copy autoexec.bat avtoexec.bat 1 files copied C:\>dir a*.bat Volume in device C is labeled MASTER Serial volume number: 1A12-140D Folder contents C:\ AUTOEXEC BAT 161 11/25/03 18:52 AUTOEXEC.BAT AVTOEXEC BAT 161 11/25/03 18:52 avtoexec.bat 2 files 322 bytes 0 folders 3,773.19 MB free C:\ > Go to plan
Dictionary Driver is a special program that controls the device connected to the computer. The filename consists of its own filename and extension, separated by a dot. The file name itself contains 1 to 8 characters, and the extension 1 to 3 characters. An interface is a way for a person to communicate with a computer. A directory is a named group of files on a flexible or hard disk. magnetic disk. Resident programs are programs that reside permanently in the computer's RAM (operating shells, device drivers, etc.). A file is a named collection of bytes written to disk. This collection does not necessarily occupy a contiguous area of memory on the disk. File system A computer is a collection of logical drives and directories that contain individual files. Back
Glossary (continued) What is CONFIG . SYS and AUTOEXEC . BAT? 1) CONFIG. SYS contains directives and commands designed to: a) load device and memory drivers; b) setting some system parameters (for example, the number of buffers and the number of simultaneously open files); c) system optimization (RAM allocation, disk data compression, disk caching). CONFIG directives. SYS are executed by the system before the COMMAND is loaded. com. 2) AUTOEXEC . BAT contains commands that you think the system should run at the start of each session. In principle, these commands can also be entered manually. Any of the CONFIG files. SYS and AUTOEXEC . BAT may be missing, in which case the system settings are set by default. Back
slide 1
Operating system MS-DOS
Without controlling the hardware, the program remains just a piece of literature written in a special formal language.
slide 2
Software
They are divided into three groups: Operating systems (OS) Programming systems (SP) Software Products(applications - APP, or application packages of APP)
slide 3
The first to appear were narrowly oriented software products (“a program designed to calculate the number with an accuracy of up to 20 digits”, “a program designed to calculate and print a payroll”, etc.); Then - Programming Systems ( early versions were called programming automation systems); Then there are Operating Systems.
Any end goal computer program– hardware management.
slide 4
Program levels
The level of open PP is designed for a qualified end user or to the administrator information system who understand the structure of the tasks to be solved, the principles of using computers for their implementation. The SP level is designed for an application programmer who develops software or software, or for a system programmer who develops OS, SP, software. The OS level is designed for the computer operator, the user responsible for the passage of tasks through the machine. The level of closed PPP is designed for a subject specialist who uses a computer to solve specific problems.
slide 5
Operating system (OS)
Complex software tools that manage computer resources. The necessity of the OS lies in the fact that the devices included in the computer understand only low-level commands (simple commands), and the ones necessary for the user consist of hundreds and thousands of elementary operations. OS deals with compatibility issues different devices, because all of them can be produced by different companies, have different features. Various companies are involved in the development of the OS, we will consider the OS created by Microsoft.
slide 6
This program is an intermediary between a person and a computer. Launches application programs for execution, manages computer computing resources and provides a user-friendly interface. The first version was developed in 1981. It is a single user operating system. Used by experts maintenance computer science when carrying out work on the repair, adjustment and configuration of equipment and programs.
Slide 7
Current at present
The basic principles of MS-DOS are used in MS-Windows. In practice, many programs under her management work well. New applications written for MS-DOS are being created. In 1997 Caldera began work on adapting DR DOS (similar to MS DOS) to the embedded OS market for small, high-precision devices connected to the Internet and Internet networks. These devices include cash registers, fax machines, personal digital assistants, electronic notebooks and etc.
Slide 8
Disadvantages of MS-DOS
MS-DOS works with 640 Kbytes of RAM. Does not allow you to work with downloadable drivers for various video cards. Single-tasking (starting several programs is not possible with switching between them). Interface command line provides only one line of the screen in which he can enter commands. Commands must be written in MS-DOS and must be memorized to work on this system.
Slide 9
Principle of operation
The entire program operation cycle is a sequence of predetermined procedures - input procedures, conversion procedures, calculations, etc. - So given environment called procedural. To simplify the work are special applications, which are called shells. Starting with Windows 95, this is no longer a shell, but a graphical OS.
Slide 10
Load Order
The process of reading the OS is called booting. OS loading starts after turning on the system unit and automatic testing, which is the first stage in the operation of the OS. It is produced by programs from the BIOS, which are recorded in non-volatile memory. All PC devices to which power is supplied by this moment are subject to testing.
slide 11
After a successful automatic test, the BIOS hardware initiates the system boot process. If the process is properly organized, in order to bring the PC into working condition, you need to turn on the power and wait for the download to finish. Management can be done both from the keyboard and the mouse, but only after loading a special driver. Drivers should be loaded from a batch file when the computer starts. In this case, they will work more stably.
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User interface An interface is a junction of two dissimilar elements of a system that ensures their interaction. Note: It can be two devices or a PC and a user. The OS defines the interface of the user and the computing system. The interface can be software and hardware.
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File Format Files can store different kinds information: text, graphics, programs, etc. The content of files is determined by their format. A file format is a language element that symbolically describes the representation of information in a file. The following parameters are used to characterize a file: Full file name; file size in bytes; file creation date; file creation time; file attributes: R (Read Only) - read only; H (Hidden) - hidden; S (System) - system; A (Archive) - archival. The concept of a logical disk is closely related to a file. The logical disk is created and managed special program(driver). It can be created on a hard disk, on a floppy disk, on a CD, in RAM. The logical drive may have unique name in the form of a single Latin letter. A hard drive can have multiple logical drives.
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MS - DOS prompt to work When DOS is ready to work, it issues a prompt as a signal of readiness, which appears in the command line at the bottom of the screen. The DOS prompt contains information about the current drive and directory. For example: A:\> - root directory on drive A: C:\ TEXT\> - drive C:, TEXT directory
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Methods of user dialogue with MS - DOS In the MS DOS system, the user communicates with the operating command in the form of commands. A command is a string of characters entered by the user in response to an MS DOS prompt that tells the operating system what action it should take.
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<команда> [<имя1> ...<имя N>/K1...KN ] General form commands Command name Keys A DOS command consists of the command name and possibly options, separated by spaces. Command entry is completed by pressing the key. Enter Files (directories)<команда>/? – command help output The system does not distinguish between lowercase and uppercase letters.
7 slide
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Command Entry Rules An MS-DOS command is always followed by a space followed by one or more parameters. Parameters are set via /(Slash). Commands and parameters can be entered in both upper and lower case, or combinations of both. You cannot use specification and file separators if a colon or space is already present there. If no parameters are specified, then the default parameters (Default) are used. When prompted by the system “Press any key” – (press any key), the user must press an alphabetic or numeric key or Enter. DOS prompt C:\> C - drive C: - logical drive\ - root directory Designations used when entering commands: - name of the logical device - path - name of files or directory
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SYSTEM COMMANDS Internal (resident) Included in the command processor External (transitive) Stored in separate files
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Internal commands Directory display command: dir Change current directory command: cd Create directory command: md Remove empty directory command: rd Monitor screen clear command: cls File delete command: del filename or erase Rename file: ren Display DOS version: ver Print disk label :vol Input current date: date Enter the current time: time
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External commands Set file attributes command: ATTRIB File copy command: COPY File concatenation (merge): COPY Create or update a label on a disk or diskette: LABEL Display all directory paths and list shared files: TREE Content output command text file to the screen: Type Deleting a directory tree (with files): DELTREE Exit from the DOS shell: EXIT Paging command for displaying information on the screen: MORE
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MS Programs and Utilities - DOS Program hard drive configuration for MS - DOS: FDISK Program for formatting logical disks: FORMAT Program for transferring system files to disk: SYS Program for editing input commands: DOSKEY.COM Command for moving files or directories to another directory: MOVE Program for checking and repairing disks: SCANDISK Program for checking file and directory structures, file allocation tables, displays disk statistics: CHKDSK Program for eliminating file fragmentation and optimizing the placement of information on the hard disk: DEFRAG Program for recovering accidentally deleted files: UNDELETE Program for recovering files after formatting: UNFORMAT Program for displaying used memory: MEM
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Working with files and directories in DOS Creating text files copy con
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Deleting del files
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copy files
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Move files< Name файла>< Name каталога>move< Name файла>:<новое Name файла>Examples Move\text\*doc a: - transfers files with extension .doc to disk and Move/y*.doc text - transfers files of type .doc d to directory text on the same disk. Files with the same name as those being forwarded will be replaced without warning. Connection (concatenation) of copy files
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Working with directories Changing drive Example: a: - change to drive a: b: - change to drive b: c: - change to drive c:
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Browse directory Dir[
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Create a directory md Path\ Examples md text - create a subdirectory Text in the current directory md a:\diplom - create a subdirectory diplom in the root directory of drive a: Copy directory copy
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Deleting an empty directory Rd Path\ Examples rd text - deleting the Text subdirectory in the current directory rd a:\diplom - deleting the diplom subdirectory in the root directory of the drive which has no subdirectories or files. To remove non-empty directories, use the DelTree program (deleting a tree) Deltree
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Disadvantages of the MS Operating System - DOS MS-DOS works with 640 Kbytes of RAM. Does not allow you to work with downloadable drivers for various video cards. Single-tasking (starting several programs is not possible with switching between them). The command line interface provides just one line of screen where he can enter commands. Commands must be written in MS-DOS and must be memorized to work on this system.