It is not uncommon for PC users to have to dig into BIOS settings. There are many questions and problems here, since on various motherboards there are sewn different types of BIOS. Menu items differ in name and location, but in general they perform similar functions.

The own type of BIOS is integrated by the motherboard developers themselves or by third-party companies that have concluded an agreement with the manufacturers. The market is dominated by third-party companies.

Three main types of BIOS should be distinguished:

• AWARD

Let's dwell on these types and consider in more detail the interface and distinctive features.

It is a leader in this field. Back in 1998, Award Software was bought by Phoenix, but BIOS is still labeled as Award.

Traditionally, the base system shell has a blue (grey) background with English menu items. The interface is different in different versions.

For example, in version 4.51 PG, navigation is visually divided into two vertical compartments. At the very bottom are the control keys.

If we consider version 6.0, then surprisingly the appearance already looks different. The gray color scheme prevails. The menu items have different names. The main sections are arranged horizontally. In the column on the right, there is a brief background information.

Takes an honorable second place. It is the property of American Megatrends Incorporated, hence the abbreviation AMI. In all respects, the similarity with the AWARD BIOS is noticeable. The names and location of the main sections coincide, but not always.

The presence or absence of BIOS options primarily depends on the manufacturer of the motherboard and its functions. Therefore, it is impossible to single out specific features of AMI unambiguously. Also, different versions have different interfaces.

The appearance of BIOS versions 2.5x (2.6x)

And this is what BIOS 3.31 looks like

UEFI BIOS:

The third type of BIOS is a truly modern technology. It has a graphical interface, something even resembles an operating system.

The menu is made in the form of pictures with inscriptions. Without knowing English, you can intuitively guess what this or that section is responsible for.

It has a big advantage over the old types. As you know, the traditional BIOS, due to its functional limitations, is able to see no more than 2 TB. UEFI breaks the limits, as there are practically no volume limits.

The new software boasts a rich set of system utilities. It is possible to backup data or optimize the operation of RAM. The following features should be highlighted:

1. Convenient interface;
2. Ability to control the mouse;
3. Expanding functionality by adding new utilities;
4. Internet update;

Of course there are many more benefits. Large manufacturers have already begun the transition to a new type of BIOS. UEFI technology has proven itself only from the best side, it is not for nothing that such giants as Intel and Microsoft are interested in it. I bring to your attention a video.

How to find out the type and version of BIOS

There are cases when you need to find out the current BIOS version. This can be done in the operating system Windows 7, XP. To do this, click "Start" - "All Programs" - "Accessories" - "Utilities" - "System Information". In the window that opens, find and read the item “BIOS version”.

At its core, there is no big difference between AMI and AWARD. They perform the same function, the distinctive differences were discussed above. Particular attention should be paid to UEFI, since this type of BIOS is a new technology with high functionality.

If you were looking for BIOS settings in pictures, then you have come to the right place.

The changes made will be protected by a lithium battery built into the motherboard and maintaining the required parameters in the event of a voltage loss.

Thanks to the program, it is possible to establish a stable interaction of the operating system (OS) with PC devices.

Attention! The present Boot network configuration section allows you to adjust parameters regarding system boot speed, keyboard and mouse settings.

After completing the work or familiarizing yourself with the Bios Setup Utility menu, you must press the burning Exit key, which automatically saves the changes made.

Section Main - Main menu

Let's start with the MAIN section, which is used to modify the settings and adjust the timing.

Here you can independently set the time and date of the computer, as well as configure the connected hard drives and other drives.

To reformat the working mode of the hard disk, you need to select the hard disk (for example: "SATA 1", as shown in the figure).

• type- this item indicates the type of connected hard disk;
• LBA Large Mode- Responsible for supporting drives larger than 504 MB. So the recommended value here is AUTO.
• Block (Multi-Sector Transfer) - For faster work, we recommend choosing the AUTO mode here;
• PIO Mode- Enables the hard drive to operate in legacy data exchange mode. It would also be best to select AUTO here;
• DMA Mode- gives direct access to memory. To get a faster read or write speed, select AUTO;
• smart monitoring- this technology, based on the analysis of the operation of the drive, is able to warn of a possible drive failure in the near future;
• 32 bit data transfer This option determines whether the 32-bit communication mode will be used by the standard IDE/SATA chipset controller.

Everywhere, using the "ENTER" key and the arrows, the Auto mode is set. The exception is subsection 32 Bit Transfer, which needs to fix the Enabled setting.

Important! It is required to refrain from changing the "Storage Configuration" option, which is located in the "System information" section and not to allow correction "SATADetectTimeout".

Section Advanced - Additional settings

Now let's start setting up the basic PC nodes in the ADVANCED section, which consists of several sub-items.

Initially, you will need to set the necessary processor and memory parameters in the Jumper Free Configuration system configuration menu.

By selecting Jumper Free Configuration, you will go to the Configure System Frequency / Voltage subsection, here you can perform the following operations:

• automatic or manual overclocking of the hard drive - AI Overclocking;
• change of clock frequency of memory modules - ;
• Memory Voltage;
• manual mode for setting the chipset voltage - NB Voltage
• changing port addresses (COM, LPT) - Serial and Parallel Port;
• setting controller settings - onboard devices configuration.

Power section - PC power

The POWER item is responsible for powering the PC and contains several subsections that need the following settings:

• Suspend Mode- set the automatic mode;
• ACPI APIC- set Enabled;
• ACPI 2.0- fix the Disabled mode.

BOOT section - boot management

Here it is allowed to define a priority drive, choosing between a flash card, a disk drive or a hard drive.

If there are several hard drives, then the priority hard drive is selected in the Hard Disk sub-item.

The boot configuration of the PC is set in the Boot Setting subsection, which contains a menu consisting of several items:

Hard drive selection

The boot configuration of the PC is set in the Boot Setting subsection,

• Quick Boot– acceleration of loading of OS;
• Logo Full Screen– disabling the screen saver and activating an information window containing information about the download process;
• Add On ROM- setting the order on the information screen of modules connected to the motherboard (MT) through slots;
• Wait For 'F1' If Error- activation of the function of forced pressing "F1" at the moment the system identifies an error.

The main task of the Boot partition is to determine the boot devices and set the required priorities.

• ASUS EZ Flash- using this option, you have the ability to update the BIOS from such drives as: floppy disk, Flash disk or CD.
• AI NET– using this option, you can get information about the cable connected to the network controller.

Section Exit - Exit and save

Particular attention should be paid to the EXIT item, which has 4 operating modes:

• Save Changes- save the changes;
• Discard Changes + EXIT- leave the factory settings in effect;
• Setup Defaults- enter the default parameters;
• Discard Changes- we cancel all our actions.

The following step-by-step instructions explain in detail the purpose of the main sections of the BIOS and the rules for making changes to improve PC performance.

Bios setting

Bios settings - Detailed instructions in pictures

BIOS (Basic Input/Output System - basic input/output system) is a program for initially starting a computer, setting up hardware, and providing input/output functions. The BIOS setup program may be called BIOS Setup Utility or CMOS Setup Utility. The abbreviated names of this program are often used, for example, BIOS Setup or just Setup. Sometimes the setup program is simply called the BIOS, but this is not entirely correct, since Bios Setup is one of the BIOS components.

The BIOS performs the following main functions.

Performs self-testing of iron when the supply voltage is turned on, while running the program computer self test when power on (Power On Self Test - POST).

It initializes input-output devices (I/O). Part of the initialization is performed precisely by hardware and software tools that are integrated into the air-blast adapters.

Ensures the loading of the RAM and executes the program BOOT - OS bootloader.

Handles software interrupts from an I/O device and maintains their functions. For all standard peripherals, the BIOS stores a maintenance program. Some of which are downloaded separately and also stored in a separate area of ​​disk memory.

Provides a computer configuration setting. To do this, the BIOS uses a special PC setup program - Setup BIOS. The BIOS includes a separate CMOS technology chip or a component of the chipset and it stores the configuration parameters of the computer - RTC RAM.

Provides the interaction of PC hardware components with the OS when it is loaded and using driver software.

Flash BIOS stores software in the form of a “hard product” - Firmware. Unlike Software, the code for this type of software is permanently stored on the computer, so that for automatic activation of BIOS programs, it is enough just to turn on the power of the computer. BIOS contains the following types of programs.

Equipment self-test program when the supply voltage is turned on - POST.

BIOS expansion programs. In parallel with self-testing, the program for initialization (programming) of registers of air-blast controllers and adapters is launched. Some checks not included in older versions of the BIOS can be performed by expanding it on UVR adapter cards.

Operating system boot program. Initialization is completed by transferring control to the operating system loader program - BOOT.

Subroutines for handling interrupts from the air conditioner.

Function maintenance subroutines. For each standard peripheral device during flash BIOS service routine is stored.

Driver programs designed to interact with the OS and hardware when the system boots.

Computer configuration program - Setup.

Initialization and testing of computer nodes.

Each time you turn on the power of an IBM PC (or a compatible PC) and before the operating system starts, the computer's processor performs a BIOS routine called the Power On Self Test (POST). The same procedure is also performed by pressing the RESET button or the Ctrl-Alt-Del key combination. The main purpose of the POST procedure is to check the basic functions and subsystems of the computer (such as memory, processor, motherboard, video controller, keyboard, floppy and hard drives, etc.) before loading the operating system. This insures the user to some extent from trying to work on a faulty system, which could lead, for example, to the destruction of user data on the HDD. However, a new specification for PC 2001 computers is currently being developed, which provides for a reduction in the time interval from the moment the PC is turned on to the launch of the disk loader to 7 seconds (in the presence of SCSI devices - up to 10 seconds), including by reducing the POST procedure, which, in general, it should not please computer assemblers / repairers, and thoughtful users, too, I think: it’s better to lose 2 minutes than to restore the contents of the HDD later or wonder why the computer began to freeze so often. In the meantime, computers continue to delight professional computer assemblers/repairers with their built-in POST procedure, so let's look at the possibilities it provides for computer repair.

Before starting each of the tests, the POST procedure generates a so-called POST code, which is output to a specific address in the address space of the computer's input / output devices. If a fault is detected in the device under test, the POST procedure simply "freezes", and the previously displayed POST code uniquely determines which of the tests "freezes" occurred. Thus, the depth and accuracy of diagnostics using POST codes is completely determined by the depth and accuracy of the tests of the corresponding BIOS POST procedure on the computer.

The port addresses for outputting POST codes depend on the type of computer: ISA, EISA - 80h, ISA-Compaq - 84h, ISA-PS / 2 - 90h, MCA-PS / 2 - 680h, some EISA - 300h, but in most cases (you can say, standard) port 80h is used. Since the POST procedure appeared in the IBM PC / XT with an eight-bit ISA system bus, it historically happened that POST codes are just one byte, which is given in POST code tables as single-digit hexadecimal numbers in the range 00h-FFh (0- 255 in decimal notation). It should be noted that the tables of POST codes are different for different BIOS manufacturers and, due to the emergence of new tested devices and chipsets, are somewhat different even for different versions of the same BIOS manufacturer. POST code tables can be found on the respective websites of BIOS manufacturers: for AMI it is http://www.ami.com, for AWARD - http://www.award.com, sometimes POST code tables are given in motherboard manuals (for example, manuals for P6SBA-P6DBS Supermicro boards).

To display POST codes in a human-friendly form, devices called POST Cards are used. POST Card is a common computer expansion card that is inserted (when the power is off!) into any free (corresponding to its connector - ISA or PCI) slot and has two seven-segment indicators for displaying POST codes. Previously, before the advent of the PC 99 and PC 99A specifications, the POST Card for the ISA bus was the most common. Now, due to the threat of the complete elimination of the ISA bus, more expensive POST Cards for the PCI bus have begun to appear. For laptops that do not have ISA and PCI buses at all, POST Cards are available for installation in an LPT port. It should be noted that for the operation of such a POST Card, appropriate support is required from the BIOS "a laptop.

Rice1. POST Cardfor tiresISA.Author's version.

The simplest POST Card for the ISA bus from vendor noname displays POST codes at the fixed address 80h and has no switches to change that address. The passage of the RESET signal of the computer to such a POST Card is fixed by the blinking of the dots of the seven-segment POST code indicator or is displayed on it with special characters. More expensive POST Cards have switches for selecting the POST code port address, as well as additional LED indicators for the RESET and CLK signals of the system bus and indicators for the presence of supply voltages +5V (+3.3V), -5V, +12V, -12V. Such POST Cards are produced, for example, by Ultra-X, Inc (http://www.uxd.com) for ISA - QuickPOST PC and PCI - QuickPOST PCI buses, respectively. The same company also offers a POST Card for connecting to the LPT connector of laptops - MICRO POST. The original POST-Probe PCI from Micro2000, Inc (http://www.micro2000.com) is very interesting. On two adjacent sides of the PCI and ISA bus connectors are located at an angle of 90 degrees. It also includes an additional adapter for connecting to our exotic MicroChannel bus. Another POST Card manufacturer is DataDepot Inc (http://www.datadepo.com), which produces both the simplest POST Card (MiniPOST) and the more complex PocketPOST. However, the PHD 16 for the ISA (Professional Hardware Diagnostics) bus from Ultra-X, Inc. can be called a real professional tool. PHD 16 has two modes of operation: diagnostics and POST codes, which are selected by setting the appropriate jumpers. In the POST code mode, the codes generated by the POST system are simply displayed on a two-digit seven-segment PHD 16 indicator. The diagnostic mode is divided into the training mode - a long run of tests to detect floating errors and the mode of finding and eliminating serious damage to completely "dead" systems, in which the standard BIOS of the motherboard is replaced by ROM BIOS Ultra-X with a special set of in-depth tests. As new motherboard chipsets are released, updated Ultra-X BIOS ROMs are also released. The results of the PHD 16 tests are displayed in a special code on a seven-segment display and additional LEDs, and if the video adapter is working, on the computer monitor. The more modern PHD PCI from Ultra-X, Inc. is designed for the PCI bus and, unlike the PHD 16, does not need an external video adapter, as it has a built-in standard SVGA video output for displaying test results on a monitor.

To better understand how to use the POST Card, consider a typical sequence of tests performed by the POST procedure:

Processor testing.

Checksum ROM BIOS.

Verification and initialization of the DMA, IRQ and 8254 timer controllers. After this stage, audio diagnostics become available.

Checking memory regeneration operations.

Testing the first 64 kB of memory.

Video controller initialization. After this step, diagnostic messages are displayed on the screen.

Testing the full amount of RAM.

Keyboard testing.

Testing CMOS memory.

Initialization of COM and LPT ports.

Initialization and test of the FDD controller.

Initialization and test of the HDD controller.

Search for additional ROM BIOS modules and initialize them.

Calling the operating system loader (INT 19h, Bootstrap), if the operating system cannot be loaded, an attempt to start ROM BASIC (INT 18h); on failure - system halt (HALT).

Before testing a computer using a POST Card, it is necessary to determine the BIOS manufacturer of the motherboard: this can be done either by the sticker on the BIOS chip, or by the inscriptions that are displayed on the screen by a similar working motherboard. Then you should find the appropriate POST code table for this BIOS: AMI - http://www.ami.com, AWARD - http://www.award.com.

The sequence of actions when repairing a computer using the POST Card is as follows:

Turn off the power of the faulty computer.

Install the POST Card in any free slot on the motherboard.

We turn on the power of the computer and read the corresponding POST code from the POST Card indicator, on which the computer boot "hangs".

Using the tables of POST codes, we determine which of the tests had problems and comprehend the probable causes.

When the power is off, we rearrange jumpers, cables, memory modules and other components in order to eliminate malfunctions.

We repeat points 3,4,5, achieving a stable passage of the POST procedure and the start of loading the operating system.

With the help of software utilities, we perform the final testing of hardware components, and in the case of floating errors, we carry out a long run of the corresponding software tests.

When repairing a computer without using the POST Card, points 2-4 of this sequence are simply omitted and from the outside, computer repair looks just like a feverish rearrangement of jumpers, memory, processor, expansion cards, power supply, and, to top it all, the motherboard. If large firms have a large stock of serviceable components, then for small firms and individuals, repairing a computer by installing known-good components becomes a difficult problem. It is even harder for service engineers who quickly travel to the customer and are forced to take a whole suitcase of spare parts with them. It happens that the replacement of computer components under the bewildered questions of the client stretches for hours and does not always lead to the desired result - you have to pick up the system unit or go for a new portion of serviceable parts.

How, in practice, is a computer repaired using a POST Card?

First of all, when the power is turned on, before starting the POST procedure, the system must be reset by the RESET signal, which is indicated on the POST Card by special characters or an LED. If the computer malfunctions in the most difficult case, the reset either does not work at all, or it does, but no POST codes are displayed on the indicator. In this case, it is recommended to immediately turn off the computer and remove all additional boards and cables, as well as memory from the motherboard, leaving only the motherboard itself with the processor and POST Card installed connected to the power supply.

If the next time you turn on the computer, the system resets normally and the first POST codes appear, then, obviously, the problem lies in the temporarily removed computer components; it is also possible, in incorrectly connected cables (especially often the IDE cable is inserted "upside down"). By inserting sequentially the memory, video adapter, and then other cards, and observing the POST codes on the indicator, a faulty module is detected. In case of a faulty memory for computers with AMI BIOS, the POST code sequence usually stops at code d4 (for older 386/486 boards - at code 13); with AWARD BIOS - on codes C1 or C6. It happens that it is not the memory itself that is faulty, but, for example, the motherboard - the reason is poor contact in the SIMM / DIMM connectors (contacts are bent / closed to each other), or the memory itself is not fully inserted in the connector.

In case of a faulty video adapter for computers with AMI BIOS, the sequence of POST codes stops at codes 2C, 40 or 2A, depending on the BIOS modification, or skips these codes without the corresponding video card initialization lines appearing on the monitor (indicating the type, amount of memory and the manufacturer of the video adapter) .

Similarly, for computers with AWARD BIOS, if the video adapter fails, the POST code sequence either stops at code 0d, or skips this code (this is especially common on new Pentium I / Pentium II motherboards).

If the initialization of the memory and video adapter went well, then by installing the remaining cards one at a time and connecting the cables, based on the readings of the POST Card indicator, it is determined which of the components sits on the system bus and prevents the computer from booting.

Now let's return to the case when the initial reset of the system does not even pass (at the very beginning of the test, special characters do not appear on the POST Card indicator indicating the passage of the RESET signal or the corresponding LED does not light up). In this case, either the computer's power supply is faulty (for example, the PWRGOOD signal is not generated), or the motherboard itself (the RESET signal generation circuits are faulty).

The exact cause can be determined by connecting a known-good power supply to the motherboard.

Let us now consider the case when the reset signal passes, but no subsequent POST codes are displayed on the indicator; in this case, as described earlier, a system is tested, consisting only of the motherboard, processor, POST Card and power supply. If the motherboard is brand new, then the cause is usually incorrectly set jumpers for selecting the frequency / multiplication / type of processor, sometimes - an incorrectly set Clear / Normal CMOS jumper. Very often, the reason for the failure is not pressing the processor to the stop in Slot 1 or the inverted position of the 486th processor. At the same time, if power is supplied to the motherboard with an incorrectly inserted processor for longer than 1-2 seconds, a complete failure of both the processor and the motherboard is possible.

From practice, it can be argued that the use of the POST Card, along with a good reaction from the engineer and a quick power off, has already saved the life of more than one processor and motherboard.

If all the jumpers and the processor are set correctly, but the motherboard still does not start, you should replace the processor with a known good one. If this does not help, then we can conclude that the motherboard or its components are malfunctioning (for example, the cause of the malfunction may be damage to information in the FLASH BIOS).

In conclusion, I would like to note that the main advantage of the POST Card is that it does not require a monitor for its operation, and testing a computer using the POST Card is possible at the early stages of the POST procedure, when sound diagnostics are not yet available, and even at the stage of sound diagnostics POST codes are much easier to understand than counting the duration and number of beeps on the computer. It can be said that the POST Card is the eyes and ears of a computer repair engineer.

Who can use the POST Card? First of all, service engineers, computer assemblers, salespeople in a computer store, system administrators - everyone who has to solve problems with computers in a short time. The POST Card is also indispensable for professional motherboard repairers who make full use of the diagnostic capabilities of the POST BIOS procedure. Even convinced skeptics, after solving problems once or twice with the help of the POST Card, could no longer part with it, clutching at it in difficult cases, like a drowning man clutching at a straw. And, finally, the non-traditional use of POST Card by programmers who are very far from hardware problems is known. Since the status of the POST code port is displayed on the POST Card indicator, programmers, when debugging additional BIOS modules or programs of an industrial stand-alone control computer without a monitor, are able to track the passage of their program's checkpoints on the POST Card indicator, simply by entering conditional codes into the POST codes register. For example, when programming in Turbo Pascal, in order to display the number 5Ah on the indicator of a POST Card operating at address 80h, you can use the statement:

port[$80]:=$5A;

And, finally, anticipating questions about where you can buy a POST Card? Industrial POST Card manufacturers classify computer repair equipment as professional, so if you have $100-150 (and for PHD PCI the price goes up to $1000), you can order a POST Card on the websites of the above manufacturers. The second way out is self-assembly of the simplest POST Card for the ISA bus. This POST Card with 8-LED binary code error indicator contains 4 widely available K555 (74LS) series ICs and can be made by even a novice radio amateur in 1-2 evenings, and the manufacturing cost is minimal.

The ISA bus is still quite popular, especially considering the fact that the simplest POST Card proposed for manufacturing will serve to repair a large number of already existing computers with the ISA bus. It is worth paying attention to the fact that many of the latest motherboards with the I820 chipset have one ISA slot. Therefore, I think that the simplest POST Card for the ISA bus will find application for at least another 2-3 years. In addition, the implementation of a POST Card for the PCI bus is rather complicated, since it requires special high-speed FPGAs and a specially made printed circuit board, and is not available to a novice radio amateur.

The scheme of the simplest POST Card is presented on figure 2, in the same place, for ease of installation, there is a drawing of the expansion board with the numbering of the pins of the ISA connector. On the DD2, DD3, DD4 chips, an output device address decoder is made with a fixed address 080h, which is most often used for issuing POST codes. The POST code values ​​coming from the SD0-SD7 data bus are fixed in the eight-bit register DD1 and displayed in binary form by the HL0-HL7 LEDs.

Any circuit board that has at least the first part of the ISA connector (pins A1-A31, B1-B31) is suitable for making a POST Card. As a last resort, you can use the lower part with the ISA connector cut off from the old faulty MIO or VGA adapter, attaching a small piece of the circuit board to it with two M3 screws. All connections on the circuit board are made with a thin stranded MGTF wire after the installation of discrete elements. In the design, you can use DD1 microcircuits of the K555IR23, DD2-K555LA2, DD3.4 - K555LE1 type, as well as their analogues from the K1533, K1531, K531 series (foreign 74LS, 74ALS, 74HC, 74F). LEDs HL0-HL7 must be placed in one row in the following order (from left to right):

HL7 HL6 HL5 HL4 HL3 HL2 HL1 HL0

These LEDs will display the POST code in binary form: the lit LED corresponds to logical 1, the off LED corresponds to 0. (HL7, HL6, HL5, HL4) and lower (HL3, HL2, HL1, HL0), then, using Table 1, determine your own hexadecimal character for each half and mentally combine these characters in the correct order: the upper half corresponds to the higher character, and the lower one - junior. With some training, this whole procedure can be done in the mind.

Table 1. Converting binary POST codes to hexadecimal

After assembling the POST Card, you need to test it. To do this, you can use any program that allows you to enter arbitrary values ​​\u200b\u200bin the range 00h-FFh into the output device at address 080h, while you need to make sure that the POST Card indicator readings correspond to the data output to port 080h. Such a program can be obtained here: posttest.zip(4 Kb), in addition, it can be used for learning and training when translating POST codes from binary to hexadecimal.

What improvements can be proposed for the simplest POST Card? First of all, it is desirable to add the DD5 register (K555TM2) with the HL8 LED to fix the passage of the RESET signal (circuit on figure 3). The RESET signal is generated by the computer's power supply when it is turned on, or when the RESET button is pressed. In the event of a complete failure of the motherboard with the installed processor, it may turn out that no POST codes are generated by this system, and the simplest POST Card ( figure 2) in this case will display random garbage that will be entered into the DD1 register each time the power is turned on. This garbage can be misinterpreted as some kind of POST code. If you install an additional register DD5 ( figure 3), then when a RESET signal is received and before the first POST code is written to the DD1 IC, all LEDs HL0-HL1 POST codes will be extinguished by a high level at pin 1 of DD1. In addition, by a short flash of the HL8 LED, it will be possible to judge the passage of the RESET signal.

As a second improvement, we can propose the introduction of a decoder - a binary to seven-segment converter for displaying POST codes on a conventional two-digit seven-segment indicator. Unfortunately, I am not aware of standard one-two-bit microcircuits for converting a full four-bit binary code to seven-segment, but they can be replaced, for example, with programmable ICs. Schemes of the simplest seven-segment decoders, along with firmware for K155PE3, were published in the Radio magazine (for example, Radio N 12 for 1987, page 55). With some redundancy as a decoder, you can also use the more affordable IS UFRZU K573RF2 (6). However, even the simplest POST Card displaying POST codes in binary form on 8 LEDs will significantly reduce the time for troubleshooting and, I hope, make life much easier for many computer assemblers/repairers!

We all have at least the slightest idea of ​​how a computer works. We know that when you turn on the computer, the operating system is loaded. But not everyone knows what happens before the operating system loads. This article will discuss what the BIOS is, its functions, how it works.

When you turn on the computer, even before loading the operating system, the BIOS comes into operation, which is responsible for starting the computer, testing computer components, setting the parameters of these components, and implementing input-output functions.

Without the BIOS, the computer will not understand where to load the operating system from, how to adjust the fan speed, with what parameters to start the computer components ...

The BIOS is stored on a flash memory chip.

You can enter the BIOS after turning on the power of the computer by pressing the DELETE, F2, or other key. This must be indicated in the instructions for the motherboard.

Basically, you need to enter the BIOS and configure it when installing the operating system and repairing the PC. Remember that incorrect BIOS settings can damage your computer.

What functions does the BIOS perform?

• Starting the computer and testing its components. The so-called POST procedure. This procedure starts as soon as the power button is turned on. The program checks all computer components and adjusts, preparing them for work. If a failure is detected, the POST procedure issues a message or a beep.
• Setting system parameters. BIOS setup. The user in BIOS Setup can change device parameters and configure part of the system or the system as a whole. For example, increase the speed of the RAM, overclock the processor. Make a boot from an optical disc (Required when installing the operating system).
• Support for I / O functions with interrupts for the keyboard, video card, hard drive, I / O ports ... Actually, this is where the general definition of the BIOS as a basic I / O system came from.

The BIOS, as we have already said, is stored on a flash memory chip. Accordingly, the BIOS can be overwritten, reflashed. This means that a newer version will be written in its place. Due to this, errors present in its earlier version are corrected, as well as new features are added, or support for new devices.

Each motherboard model has its own BIOS version, which takes into account all the parameters and functions of this motherboard. For example, new processors have entered the market and an earlier BIOS version does not support them. A flashing is done and new processors can be used. The manufacturer's website should indicate which bugs have been fixed and which features have been added in newer firmware.

Our memory chip, which stores the BIOS, is powered by a 3 volt battery. She is also in charge of the clock. It is mandatory installed on all motherboards. You can get to it by opening the side wall of the computer. When the battery is discharged and no longer performs its function, every time you turn on the PC, all BIOS settings are lost and the time is reset. That is, the battery is responsible for the safety of the BIOS settings, including the BIOS settings entered by the user. In addition, due to a discharged battery, the PC often does not start, and users think that the power supply is to blame, or the computer's power button. In this case, you need to buy a battery and put it in place of the old one. After that, you need to set the parameters, if necessary.

How does the computer start up and its components are tested? POST procedure.

After the power button is turned on, the power supply starts up first. If all supply voltages are normal, then the central processor receives a power-on signal. The CPU tests itself. After that, the RAM memory is tested. Next, the initial iron test begins. At this stage, when errors are found, a sound signal appears, since the video system has not yet been initialized. The BIOS then looks for devices that may need to boot their own BIOS. Such a device is a video card. Then, peripheral devices, such as a mouse, a hard drive, are initialized and configured. Then the BIOS, in accordance with its own priority, selects the device specified in the BIOS in order to start loading the operating system from it. It finds the operating system boot sector on that device and invokes the operating system loader. Then the operating system is loaded. That's how important the BIOS is.

You should also be aware that entering the BIOS can be password protected. This is to prevent you from making changes. You can fix this either with a BIOS clearing jumper (far from being installed on all motherboards) by connecting the connectors with a screwdriver, or by pulling out the battery and inserting it back. All settings will be reset.

We hope this article has given you the answers to your questions.

13. 05.2017

Blog of Dmitry Vassiyarov.

What is a BIOS in a computer - let's figure it out

Hello guests of my blog.

Any modern person should know what a bios is in a computer. After all, without it, the computer is a simple set of pieces of iron. It is important to be able to understand this issue in order to independently configure the system and determine which components are out of order. Knowing the BIOS will help you better understand your computer. This article will be partly superficial.

Just about the unknown

The subject of our conversation is an English abbreviation that stands for "basic input / output system".

It translates as basic input/output system. By the way, it is correct to pronounce “bayos” in Russian, but the word “bios” has already become established in the slang of IT people.

This concept means a set of microprograms that implement software for working with computer components and peripheral devices connected to it (printer, modem, etc.). That is, in other words, this same BIOS determines and starts the work of all devices on your computer - this is the main function.

If it does not exist, then, accordingly, the hardware of your computer is simply not detected and will not start.

This is how the software part of the BIOS itself looks like:

The analogue of the BIOS is a faster and more modern technology that works in 64-bit mode, while the BIOS works mainly in 16 and 32-bit mode.

This is what the software part looks like:

Physical parameters

Where is the bios? In the motherboard, which is quite logical, because it is she who is responsible for the operation of all elements of the computer. The bios is embedded in a special chip. Do not confuse it with the CMOS chip.

There are 2 types of bios chips:

• EPROM. Old model. Its contents can be removed from exposure to a special device with ultraviolet radiation.

• eeprom. Modern version. Its contents can be erased with a special electrical signal. And even if the chip is not removed from the system unit. It doesn't always look like this. In this case, the chip itself is in the carriage, that is, it can be removed for replacement, for example, or for firmware. But often the BIOS chip is soldered directly to the board.

What else should you know about what is a BIOS in a computer and what does it consist of? There is one more moment. It has its own small battery. It looks like a lithium coin and can have different capacities (80-230 mAh). More precisely, not in the BIOS, but in the CMOS chip. The CMOS chip is the memory of the BIOS itself.

This element feeds the CMOS memory, where user parameters and BIOS settings are stored. The battery has a lifespan of several years: over time, it discharges and .

If she sits down, there will be no fatal consequences. Minimum: Resets settings that will need to be manually restored after replacing this part. Maximum: programs will start to fail and the computer will not start.

What does the BIOS do?

When you press the power button on your computer, the processor reads the BIOS code from read-only memory () and writes it to random access memory (RAM). Then control is transferred to the BIOS itself, which:

• Checks the equipment for operability;
• Analyzes settings from ROM and applies them;
• Looks for the bootloader code in the master entry on the hard disk or on the boot disk in the CD-ROM/floppy/flash drive/network;
• Transfers the code to the RAM;
• Shifts further control to the bootloader.

Without these steps, your computer will not start. If some part is broken or there was a failure in the system, the BIOS will tell you about it at the initial stage of loading.

Features available to you

With the BIOS, you can:

• Set up time;
• Set download priority;
• Set power options for hardware;
• Turn on / off this or that equipment.

How to work in BIOS?

Entering the BIOS is very simple - when rebooting or starting the computer, hold down the Delete or F2 key (depending on the type of motherboard). To manage, you need only a few buttons: arrows to move between sections, Enter to enter them and apply settings, ESC to exit.

In addition, you can return to the factory settings using the F9 key, and approve the new parameters - F10.

Let's go through some tabs:

The "Advanced" and "Security" tabs can be left untouched. The first is responsible for the operation of the equipment. The second is for the security of the computer, but for home use these settings will not be useful to you.

That's all. I think the question of what is a BIOS in a computer, I answered quite fully.

See you on our blog pages.