The operating system starts loading. What is BIOS and UEFI. How to boot a computer. General scheme of how dos works

Tired of Windows 7,8,10 loading slowly? YES, the more time the operating system is installed, the more this topic begins to torment. Computers are becoming more powerful and productive, but at the same time the demands for programs that are developed for new equipment are also growing. For example, Windows XP boots an order of magnitude faster than Windows 7/10 on the same hardware.

So now, give up new features for faster loading operating system? No, fortunately, there are tricky and not so tricky tricks that will help us solve this problem. In this article you will learn how to programmatically reduce time Windows boot up to 20 seconds or less.

Step one, services and processes

In Windows OS, unnecessary services are often launched, which slow down the loading and operation of the system. There is also support for a variety of hardware, so the services that ensure it works properly start with the system. Of course, if the system considers that the service is not necessary (since there is simply no corresponding device on the computer), then it is disabled. But starting, checking and stopping the service still takes time.

We launch the “System Configuration” program, to do this, press “Win ​​+ R”, write in the window: msconfig and press Enter. To disable temporarily unnecessary services, go to the tab of the same name:

But you need to understand which services can be turned off and which need to be left running. It is easy to find information on the Internet for most services, so I will not dwell on this in detail. I’ll just say: don’t rush and turn off everything, this can have a sad effect on the operation of the operating system.

Using the same logic, we disable programs that are loaded at system startup on the next “Startup” tab. More details are provided in a separate article. You will need to restart your computer to apply the new startup settings.

Step two, registry

There is a weak point in Windows - the registry. It just so happened from ancient times that most vital Windows settings stored in a hierarchical database. Both the loading speed and the operation of the Windows OS as a whole directly depend on the speed with which the OS finds the necessary entries in the registry.

It is not uncommon for program uninstallers to work ineffectively, leaving entries in the registry about their presence and work (parameters, registered libraries, binding to certain file extensions, etc.). Such records can be considered garbage, cluttering up the database. And you need to get rid of this garbage, for which you should use such utilities as, for example, Reg Organizer, CCleaner, Ashampoo WinOptimizer and others.

Launch CCleaner, go to the “Registry” section, click “Search for problems”, and when finished click “Fix selected”:

During such cleaning, and simply while Windows is running, the registry is constantly subject to fragmentation. This means that you will need to DEFRAGMENT the registry. This can be done using the Defraggler program, from the same developer. However, I will important note that in some cases, “cleaning” the registry may affect important parameters. Therefore, be sure to first, and in case of problems in Windows work you can immediately recover to your previous state.

Step three, the main one

Now you can begin to deeply optimize the process of loading the system and programs. During application execution, many side effects can occur, such as long loading of additional libraries and routines, conditional branch prediction, cache misses, and the like. Analyzing such data is called profiling.

Since the OS in question was created by Microsoft, we will use a profiler created by the same company - Windows Performance Toolkit. Recently, this tool has become part of the Windows SDK. On the site Microsoft You can download the web installer.

It is not necessary to install all the included components; you can only get by with the Windows Performance Toolkit

This tool allows you to trace the boot of the operating system from the very beginning. We need the executable file “xbootmgr.exe”, which is located in the folder where you deigned to install the Windows Performance Toolkit; by default, it is located in the “C:\Program Files\” directory Microsoft Windows Performance Toolkit."

Watch the video or continue reading the article:

To call the utility, run xbootmgr.exe with a parameter, for example, the “-help” parameter will display a list of all possible functions. To do this, press the “Win ​​+ R” buttons or go to the “Start -> Run” menu and enter the command in the window:

xbootmgr –help

It is not necessary to add the path to the file if it starts like this:

Just for fun, if you want to see how your system behaves when running in this moment, then run the command:

xbootmgr -trace boot

It will reboot your computer and collect data during startup. The result of her work can be seen in the file boot_BASE+CSWITCH_1.etl, which xbootmgr will save in its own folder or in the “C:\Users\yourname” folder. This file contains all the information about the behavior of programs when the system starts, you can see a lot of interesting things. To do this, double-click on the file to open the Analyzer:

If you are interested, study the information, here is everything in great detail about the download process: how many seconds it took to start each process, how computer resources were used, etc.

Now let's get down to business - let's start the process of automatically analyzing and speeding up Windows loading. Run the command:

xbootmgr -trace boot –prepsystem

During optimization, by default, 6 reboots will be performed and 6 files with information about the behavior of programs at each reboot will be saved in the same directory. This whole process is quite lengthy, but does not require user participation. You can successfully have lunch while the program is running. And don’t forget to first check that there are a couple of Gigabytes of free space on the “C:” drive!

After reboots, messages will appear in a white window, for example “Delaying for boot trace 1 of 6” with a countdown:

In this case, you don’t need to try to work on your laptop, just wait. More messages will appear. At the second stage, the “Preparing system” window hung there for about 30 minutes, while the processor was not loaded with anything, but then a reboot occurred and the remaining stages went quickly. In reality, the whole process can take an hour.

What does Xbootmgr do? It does not disable unnecessary services and processes, as it might seem. Xbootmgr optimizes booting so that maximum computer resources are used at any given time. That is, so that it doesn’t happen when the processor is 100% loaded and the hard drive is resting, or vice versa. Also happens. After the last reboot, you don’t need to do anything, Windows will boot, and even work, faster.

Step four, dangerous

In the seven, as well as in XP (although not everyone realizes this), there is support multi-core processors. It is not clear why the system itself is not always able to use all available resources when it starts, but only begins to use them when it has already fully loaded and the user has started working.

This means we need to help her use the available resources in the system startup parameters. To do this you need to delve into the configuration. Using the key combination “Win ​​+ “R”, open the “Run” window and write the command msconfig, click “OK”. In the system configuration window that appears, select the “Download” tab

Select "Advanced options"

In the window that appears, set the “Number of processors” and “Maximum memory” parameters to maximum. Now attention! Close and open the program again, see that the “Maximum memory” value has not been reset to “0”. If so, then uncheck this box, otherwise the system may won't start at all. Reboot, done.

Note: If you decide to add RAM or replace the processor with another one (with more cores), then the above parameters will need to be changed. Otherwise, the system simply will not use additional memory and/or additional processor cores.

1) all data is erased
2) a full disk scan is performed
3) the disk directory is cleaned
4) the disk becomes system
12. In a multi-level hierarchical file system...
1) Files are stored in a system that is a system of nested folders
2) Files are stored in a system that is a linear sequence

13. Path to file:
1) this is a named area on the disk;
2) this is a sequence of directory names separated by the “\” sign;
3) this is a list of files collected in one directory;
4) This is a list of directory names collected in the root directory.

14. During the archiving process, files...
1. Compressed without loss of information
2. Move to free sectors
3. Copied to another folder
4. Removed from the catalog
15. During the disk defragmentation process, each file is written:
1) In odd sectors
2) In arbitrary clusters
3) Mandatory in consecutive sectors
4) In even sectors

16. Device drivers:
1) this is hardware connected to a computer to perform input/output operations;
2) this software, intended for connecting input/output devices;
3) this is a program that translates high-level languages ​​into machine code;
4) this is a program that allows you to increase the speed of the user’s work on
17. Application programs
1) Programs designed to solve specific problems
2) Control the operation of hardware and provide services to us and our application systems
3) Games, drivers and translators
4) Programs stored on floppy disks
18. The operating system performs the following functions:
1) ensuring organization and storage of files;
2) organizing a dialogue with the user, managing equipment and computer resources;
3) data exchange between the computer and various peripheral devices;
4) connections of input/output devices.
19. During the loading process of the operating system, the following occurs:
1) Copy operating system files from a floppy disk to HDD
2) Copying operating system files from CD to hard drive
3) Sequential loading of operating system files into RAM
4) Copying the contents of RAM to the hard drive
20. System disk required for:
1) Loading the operating system
2) Protect your computer from viruses
3) Creating programs using GUI
4) Archiving and unarchiving files
21. The top of the Windows GUI folder hierarchy is the folder:
1. root directory of the disk
2. my computer
3. network environment
4. Desk
22. The dialog box in Windows is designed to
1) dialogue between the user and the computer;
2) uninstalling the program;
3) display the program icon;
4) display the program name.

23. Doesn't exist in Windows
1) program windows;
2) testing windows;
3) dialog boxes;
4) document windows.
24. Computer viruses This…
1) Programs that can reproduce and perform harmful actions to destroy programs and data
2) Programs that can infect TV programs
3) Viruses that are dangerous to human health

Chapter 2
Processing technology graphic information
31. All computer images are divided into two types:
1. raster and vector
2. black - white and color
3. complex and simple
32. Raster image created using...
1. dots of different colors (pixels)
2. lines
3. circles
4. rectangles
33. Vector images are formed from…
1. objects called graphic primitives
2. different colored dots (pixels)
3. rows and columns
4. drawings and photographs
34. For processing digital photos and scanned images, the best way is...

35. To create drawings, diagrams and drawings, the best tool is...
1. raster graphics editor
2. vector graphic editor
3. computer drawing system
36. Graphic file formats determine...
1. Method and form of storing information in a file
2. Image quality
3. Image volume
4. Image dimension
37. In vector graphic editor drawn object...
1. Continues to retain its individuality and can be scaled and moved around the design
2. ceases to exist as an independent element after the end of drawing and becomes only a group of pixels in the drawing.
38. The most common applications for developing presentations are...
1.Microsoft Power Point
2.Microsoft Access
3. Microsoft Excel
4. Microsoft Word
39. Presentation files can be saved in…
1.ppt
2. psd
3. tiff
4.doc

No. 2.Task with a short answer. How much information does it carry? binary code 10101010?

2.What parts does a file name consist of?
3.Who or what names the file?
4.Who or what assigns a file extension?
5.How many characters can a file name include?
6.How many characters are usually allocated for a file extension?
7.What needs to be done with the disk so that files can be stored on it?
8.What areas is the disk divided into when formatting?
9.In what case is the file system single-level?
10.How to write down the path to a file?
11.What kind of software does the operating system belong to?
12. What information should the operating system have to organize access to files?

13.Where is the currently running program and processed data stored?
14.What is a catalog called?
15.When does the operating system boot?
16.What is an operating system?
17.What is the name of a logical drive?
18.Which directory is called the root?
19.What is the state of the operating system called when it stops producing results and responding to requests?
20.What happens to OS files during the boot process?
21. The user, moving from one directory to another, sequentially visited the directories LESSONS, CLASS, SCHOOL, D:\, MYDOC, LETTERS. With each move, the user either went down to a lower level in the directory, or went up to a higher level. What is the full name of the directory from which the user started moving?

1) D:\MYDOC\LETTERS

2) D:\SCHOOL\CLASS\LESSONS

3) D:\LESSONS\CLASS\SCHOOL

22. Determine which of the specified file names does not satisfy the mask: ?*di.t?*

4) melodi.theme

23.The file Literature_List.txt is stored in a certain directory. In this directory, we created a subdirectory named 10_CLASS and moved the file Literature_List.txt into it. After which the full file name became D:\SCHOOL\PHYSICS\10_CLASS\Literature_list.txt.

What is the full name of the directory where the file was stored before it was moved?
1) D:\SCHOOL\PHYSICS\10_CLASS

2) D:\SCHOOL\PHYSICS

24. Which of the files matches the mask??P*.A??.

The initial stage does not depend at all on what operating system installed on a computer, for some stages in each operating system They offer their own solutions - mostly interchangeable. Let's call this stage (initial) pre-system boot. Starting from a certain stage, the computer boot is already controlled by Linux itself, utilities, scripts, etc. are used. Let's call this (final) stage system boot .

Bootloader to ROM

Immediately after switching on, the RAM of a classical architecture computer is pristine. In order to start working, the processor needs at least some kind of program. This program is automatically loaded into memory from permanent storage device, ROM (or ROM, read-only memory), into which it is written once and for all in an unchanged form 1 Modern computers use programmable ROM, the contents of which can be changed, but such a change is always considered an abnormal situation: for example, writing new version contents of the ROM in which errors have been corrected (upgrade).. IN specialized computers (for example, in cheap game consoles) everything that the user needs is recorded exactly on

Typically, in general-purpose computers, a program from ROM is of no use to the user: it is small, and it always does the same thing. You can slightly change the behavior of a program from ROM by operating with data recorded in non-volatile memory(sometimes called CMOS, sometimes called NVRAM). Volume non-volatile memory is very small, and the data from it is saved after the computer is turned off due to an autonomous power supply (usually from a battery like a clock battery).

What should this one be able to do? initial program? Recognize the main devices on which another can be recorded - needed by the user- a program, be able to load this program into memory and transfer execution to it, as well as support an interface that allows you to change settings in NVRAM. Actually, this is not even one program, but many subroutines, engaged in interaction with a variety of input-output devices - both with those on which programs can be stored (hard and floppy disks, magnetic tapes and even network cards), and those through which you can communicate with the user (serial data ports - if it is possible to connect a console terminal, a system keyboard and a video card - for simple personal workstations). This set of routines in ROM is usually called BIOS(basic input-output system).

BIOS. An abbreviation for "Basic Input-Output System", a set of routines in ROM designed for simple low-level access to external computer devices. In modern operating systems it is used only during the initial boot process.

This stage of system boot can be called zero, since it does not depend on any system. Its task is to determine (possibly with the help of the user) from which device the download will take place, download a special bootloader program from there and run it. For example, to find out that the boot device is a hard drive, consider the most first sector of this disk and transfer control to a program that is located in a few areas.

Boot sector and primary bootloader

Most often, the size of the primary disk loader - the program to which control is transferred after stage zero - is quite small. This is due to the requirements versatility this kind of programs. You can read data from the disk sectors, the size of which varies for different types disk devices(from half a kilobyte to eight or even more). In addition, if you can always read one, first, sector of a disk in the same way, then the commands for reading several sectors on different devices may look different. That's why primary loader usually occupies no more than one sector at the very beginning of the disk, in its boot sector.

If primary loader was bigger, he probably could have figured out where the core was operating system, and could independently read it, place it in memory, configure it and transfer control to it. However, the core operating system has a rather complex structure - and therefore a difficult loading method; it can be quite large, and, most unpleasant of all, it can be located in an unknown location on the disk, obeying the laws file system(for example, consist of several parts scattered across the disk). Take it all into account primary loader I can't. Its task is more modest: to determine where on the disk the “big one” is located. secondary loader, download and run it. Secondary loader is simple, and can be put in a predetermined place on the disk, or, at worst, put in a predetermined place accommodation map, describing exactly where to look for its parts (size secondary bootloader limited, so it is possible to construct such a map).

Location map. Representation of the area with the necessary data (for example, secondary loader or the system kernel) in the form of a list of disk sectors that it occupies.

For an IBM-compatible computer, the size boot sector is only 512 bytes, of which not all are found in software region. Boot sector IBM PC, called MBR(master boot record), also contains disk partition table, the structure of which is described in Lecture 11. It is clear that a program of this size cannot boast of a variety of functions. Standard on many systems boot sector can only count disk partition table, define the so-called boot partition (active partition) and load the program located at the beginning of this partition. Each type of disk can have its own MBR software part, which allows you to read data from anywhere on the disk, depending on its type and geometry. However, you can still read no more than one sector: it is unknown what the installed on this partition is used for. operating system second and subsequent sectors. It turns out that the standard software part of the MBR is a certain preloader, which reads and runs the real primary loader from the first sector boot partition.

There are versions of the preloader that provide the user with the ability to independently choose, from which partition to boot 2 For example, BOOTACTV from the pfdisk package or the standard FreeBSD preloader boot0 , which, due to their pre-system, can be used anywhere.. This allows for each of the installed operating systems keep own primary loader at the beginning of the section and freely choose among them. The standard Linux boot scheme takes a different approach: simple primary loader is written directly to the MBR and the select function is passed to the secondary bootloader.

Primary loader. The first stage of booting a computer: a program whose size and capabilities depend on hardware requirements and BIOS functions. The main task is to load secondary loader .

Kernel loader

To task operating system. Typically, the system kernel is written to a file with a specific name. But how to the secondary bootloader read the file with the kernel, if this operation exists in Linux function kernels? This problem can be solved in three ways.

First, the kernel may not be a file on disk. If the download occurs over the network, it is enough to ask the server for “a file with such and such a name”, and in response will come a solid sequence of data containing the requested kernel. All file operations will be performed by the server on which the system is already loaded and running. In other cases, the kernel is “driven” into a section specially allocated for this purpose, where it no longer lies in the form of a file, but in the same continuous piece, the size and location of which are known. However, in Linux it is not customary to do this, since there may not be space for a special partition on the disk of, say, an IBM-compatible computer.

Secondly, you can use the above location map: imagine the kernel as a set of sectors on the disk, write this set to a predetermined location, and force the bootloader to assemble the kernel from pieces on the map. Usage location maps has two significant drawbacks: its Creation only possible under control already loaded systems, and change kernels must necessarily be accompanied by a change in the map. If for some reason the system does not boot in any of the pre-planned configurations, the only way to improve the situation is to boot from external media (for example, from laser disk). And the system may not boot precisely because the administrator forgot after changing the kernel, rebuild the map: the map contains a list of sectors that correspond old file with the kernel, and after deleting the old file, these sectors may contain any kind of “garbage”.

Thirdly, you can teach secondary loader recognize structure file systems and find files there by name. This will noticeably increase its size and require “doubling functions” - after all, exactly the same, even more powerful, recognition will be in the

After turning on the computer, there is no operating system in its RAM. By itself, without an operating system, computer hardware cannot perform complex actions such as loading a program into memory. Thus we are faced with a paradox that seems insoluble: in order to load the operating system into memory, we must already have the operating system in memory.

The solution to this paradox is to use a special small computer program called bootloader, or commands located in permanent memory (for example, on an IBM PC - reboot commands without any help). This software can detect devices suitable for booting and load the OS bootloader from a special partition of the selected device itself (most often the boot sector) of these devices.

Bootloaders must comply with specific restrictions, especially regarding volume. For example, on IBM PC first level loader must fit in the first 446 bytes of the master boot record, leaving room for 64 bytes of the partition table and 2 bytes for the AA55 signature needed for the BIOS to detect the bootloader itself.

Story

Early computers had a set of switches that allowed the operator to place the boot loader in memory before the processor started. This bootloader then read the operating system from an external device, such as a punched tape or hard drive.

The pseudo-assembly bootloader code can be as simple as the following sequence of instructions:

0: write the number 8 to register P 1: check that the punched tape reader can start reading 2: if it can’t, go to step 1 3: read the byte from the punched tape reader and write it to the battery 4: if the punched tape runs out, go to step 8 5: write the value stored in the accumulator to RAM at the address stored in the P register 6: increase the value of the P register by one 7: go to step 1

This example is based on the bootloader of one of the minicomputers released in the 1970s by Nicolet Instrument Corporation.

0: write the number 106 to register P 1: check that the punched tape reader can start reading 2: if it can’t, go to step 1 3: read the byte from the punched tape reader and write it to the battery 4: if the punched tape runs out, go to step 8 5: write the value stored in the accumulator to RAM at the address stored in the P register 6: decrease the value of the P register by one 7: go to step 1

The length of the second-level bootloader was such that the last byte of the bootloader modified the command located at address 6. Thus, after step 5 was completed, the second-level bootloader started. The second-level loader was waiting to load the punched tape reader with the length of the punched tape containing the operating system. The difference between the first level loader and the second level loader were checks for errors in reading from punched tape, which were common at that time, and, in particular, on the ASR-33 teletypes used in this case.

Some operating systems, the most typical of which are older (pre-1995) operating systems Apple computers Computer are so closely tied to the computer hardware that it is impossible to load any other operating system on these computers. In these cases, it is common to develop a boot loader that acts as the boot loader for the standard OS and then transfers control to the alternative operating system. Apple used this method to run the A/UX version of Unix, and then it was used by various free operating systems.

Devices initialized by BIOS

A boot device is a device that must be initialized before the operating system boots. These include input devices (keyboard, mouse), base output device (display), and the device from which production will be made - floppy drive, hard drive, flash drive, PXE).

Boot sequence of a standard IBM-compatible personal computer

The personal computer is loading

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When the computer is turned on, control is transferred to the basic input/output system, BIOS. It checks the computer's hardware components, forms the initial part of the interrupt vector table, initializes devices and begins the process of loading the operating system.

Booting begins with the BIOS attempting to read the very first sector of the floppy disk inserted into drive A: (on a boot floppy disk, this sector contains the operating system loader). If a system floppy disk is inserted into the drive, the bootloader is read from it and control is transferred to it.

If the floppy disk is not a system one, i.e. does not contain boot entry, a message appears on the screen asking you to replace the floppy disk.

If there is no floppy disk in drive A: at all, then the BIOS reads the master boot record of drive C: (Master Boot Record). This is usually the very first sector on the disk. Control is transferred to the loader, which is located in this sector. The bootloader analyzes the contents of the partition table (also located in this sector), selects the active partition and reads the boot record of this partition. The boot record of the active partition (Boot Record) is similar to the boot record located in the first sector of the system floppy disk.

The active partition's boot record reads the IO.SYS and MSDOS.SYS files from disk (in that order). Resident drivers are then read and loaded. The linked list of device drivers begins to be generated. The contents of the CONFIG.SYS file are analyzed and the drivers described in this file are loaded. First, the drivers described by the DEVICE parameter are loaded, then (only in MS-DOS versions 4.x and 5.0) the resident programs specified by the INSTALL statements. After this, the command processor is read and control is transferred to it.

The command processor consists of three parts - resident, initializing and transit. The resident part is loaded first. It processes interrupts INT 22H, INT 23H, INT 24H, and controls the loading of the transit part. This part command processor processes MS-DOS errors and prompts the user for action when errors are detected.

The initialization part is used only during the boot process of the operating system. It determines the starting address at which the user program will be loaded and initiates execution of the AUTOEXEC.BAT file.

The transit part of the command processor is located in the highest memory addresses. This part contains handlers for internal MS-DOS commands and an interpreter for command files with the .BAT extension. The transit part issues a system prompt (for example, A:\>), waits for operator commands to be entered from the keyboard or from a batch file, and organizes their execution.

After loading the command processor and completing the initial procedures listed in the AUTOEXEC.BAT file, the system is ready for operation.

1.3. General scheme of how dos works

In order to work correctly with system software and hardware, you need to clearly understand the mechanism of interaction of the application program with the computer. In Fig. 1.1 shows the functional connections of the program with the IBM PC software and hardware.

Fig.1. Functional connections of the program for MS-DOS with PC hardware and software

Typically, the DOS kernel is divided into several subsystems, each of which is responsible for performing a particular task. As shown in the figure, the following subsystems are usually distinguished:

file system;

memory management system;

program management system;

communication system with device drivers;

error handling system;

time service;

operator console input/output system.

These subsystems communicate with the hardware through the BIOS, drivers, or directly. Application software can call DOS subsystems, work with the BIOS, or work directly with the hardware. Please note, however, that application programs can only access drivers through the appropriate DOS subsystem.

It is also obvious that the higher the level of interface between the application program and the equipment, the less the program will depend on the characteristics of the equipment.

Let's look at the DOS subsystems separately.