If you purchased an assembled computer or laptop, then its BIOS is already configured properly, but you can always make any personal adjustments. When a computer is assembled on its own, then for it to work correctly, you need to configure the BIOS yourself. Also, this need may arise if a new component was connected to the motherboard and all parameters were reset to default.
The interface of most BIOS versions, with the exception of the most modern ones, is a primitive graphical shell, where there are several menu items from which you can go to another screen with already customizable parameters. For example, the menu item "Boot" opens the user to the parameters for distributing the priority of the computer boot, that is, there you can select the device from which the PC will boot.
In total, there are 3 BIOS manufacturers on the market, and each of them has a significantly different interface. For example, AMI (American Megatrands Inc.) has a top menu:
In some versions of Phoenix and Award, all section items are located on the main page in the form of columns.
Plus, depending on the manufacturer, the names of some items and parameters may differ, although they will carry the same meaning.
All movement between items is done using the arrow keys, and the selection is done using Enter... Some manufacturers even make a special footnote in the BIOS interface, where it is written which key is responsible for what. UEFI (the most modern type of BIOS) has a more advanced user interface, the ability to control it with a computer mouse, as well as translation of some points into Russian (the latter is quite rare).
Basic settings
The basic settings include time, date, computer boot priority, various settings for memory, hard drives and drives. Provided that you have just assembled the computer, you need to configure these parameters.
They will be in the section "Main", "Standard CMOS Features" and "Boot"... It is worth remembering that the names may differ depending on the manufacturer. First, set up the date and time according to these instructions:
Now you need to configure the priority of hard drives and drives. Sometimes, if you don't do it, the system simply won't boot. All the necessary parameters are in the section "Main" or "Standard CMOS Features"(depending on the BIOS version). A step-by-step instruction using the Award / Phoenix BIOS as an example is as follows:
Similar settings need to be made for BIOS users from AMI, only here the SATA parameters are changed. Use this guide to work:
AMI BIOS users can finish the standard settings at this point, but the Award and Phoenix developers have a few more additional items that need user participation. All of them are in the section "Standard CMOS Features"... Here is a list of them:
This completes the standard settings. Usually, half of these points will already have what you need.
Advanced options
This time, all settings will be made in the section "Advanced"... It is in the BIOS from any manufacturer, although it may have a slightly different name. Inside it, there may be a different number of items depending on the manufacturer.
Let's consider the interface using the AMI BIOS as an example:
Now let's proceed directly to the settings of the parameters from the point :
Award and Phoenix do not need to configure these parameters, since they are configured correctly by default and are located in a completely different section. But in the section "Advanced" you will find advanced settings for setting boot priorities. If the computer already has a hard disk with an operating system installed on it, then in "First Boot Device" select value "HDD-1"(sometimes you need to choose "HDD-0").
If the operating system has not yet been installed on the hard disk, then instead of it it is recommended to set the value "USB-FDD".
Also at Award and Phoenix in the section "Advanced" there is an item regarding the settings for entering the BIOS with a password - "Password Check"... If you have set a password, then it is recommended to pay attention to this item and set a value that is acceptable to you, there are only two of them:
Configuring security and stability
This feature is only relevant for owners of machines with BIOS from Award or Phoenix. You can enable maximum performance or stability mode. In the first case, the system will work a little faster, but there is a risk of incompatibility with some operating systems. In the second case, everything works more stable, but slower (not always).
To enable high performance mode, from the main menu, select "Top performance" and put in it the value "Enable"... It is worth remembering that there is a risk of disrupting the stability of the operating system, so work in this mode for several days, and if any failures appear in the system that were not previously observed, then disable it by setting the value "Disable".
If you prefer stability over performance, then it is recommended to download the secure settings protocol, there are two types of them in total:
To load any of these protocols, you need to select one of the items discussed above on the right side of the screen, and then confirm the download using the keys Enter or Y.
Setting a password
After completing the basic settings, you can set a password. In this case, no one except you will be able to access the BIOS and / or the ability to change any of its parameters (depending on the settings that were described above).
In Award and Phoenix, in order to set a password, select the item in the main screen Set Supervisor Password... A window will open where you enter a password up to 8 characters long, after entering a similar window opens, where you need to write the same password for confirmation. When typing, use only Latin characters and Arabic numerals.
To remove the password, you need to select the item again Set Supervisor Password, but when the new password window appears, just leave it blank and click Enter.
In the AMI BIOS, the password is set slightly differently. First you need to go to the section "Boot", which is in the top menu, and there you will already find Supervisor Password... The password is set and removed in the same way from Award / Phoenix.
Upon completion of all manipulations in the BIOS, you need to exit it with saving the previously made settings. To do this, find the item Save & Exit... In some cases, you can use the hotkey F10.
Configuring BIOS is not as difficult as it might seem at first glance. In addition, most of the described settings are often already set by default as needed for normal computer operation.
Hello dear readers! I am pleased to see that there is already some traffic on the site. I see, though not huge, but still attendance. This gives impetus to writing new articles and reviews. And today we will analyze what a BIOS is, how it works, why it is generally needed and how important it is. So sit down more comfortably in front of the screen and get another dose of knowledge of your PC.
In previous articles about, and we have already familiarized ourselves with the main components of a laptop, it's time to dig deeper, namely bios, Windows installation, registry, etc. And today we will start with Bios. So, in every laptop there is a small microcircuit on which a small program is written when assembling a PC. The program itself is responsible for the first launch of the laptop, preparing it for installing Windows. This is called the BIOS software - the basic input and output system. As soon as you press the start button on your laptop or on the system unit, immediately this program looks for and checks the performance of individual devices, looks from which media to start the system, and sometimes displays certain requests on the monitor. It's like an intermediary between the system and your PC's hardware. The main tasks of the BIOS are:
Enable or disable some of the built-in devices, as well as their initial configuration.
Adjustment of CPU performance frequency and voltage.
Temperature control, fan control.
Switching the PC to power saving modes and vice versa.
Turn off and turn on the laptop.
Although now Windows operating systems have learned to do without BIOS for tasks such as SLEEP, HIBERNATION, LOCKING, referring directly to the hardware of the computer. If these functions are disabled in the BIOS, then they will not be available for the system either.
To view and edit BIOS settings, a special menu (BIOS Setap) is provided, which is called up at the moment of turning on or when the system itself is rebooted. Already from the factory, the program settings are made optimally according to Defaults (by default), but we still apply some changes, mainly this:
- Changing the hard disk controller mode when installing Windows 7.
Prioritizing bootable media.
Disconnection of unused or faulty devices.
Setting, changing and disabling the password for turning on the computer. (not to be confused with account password).
Calling up the settings menu or entering the BIOS.
When turning on, starting the computer, when the system emits one short signal from the system speaker, you need to press a certain key or a combination of several. To do this, you are given a couple of 2-3 seconds. If you do not have time or press the wrong key, the system will boot from the specified media. To make it easier for you to know what to press, the system prompts you like this: Press DEL to enter Setap is a suggestion to use the Delete key to enter the BIOS. Each laptop model, depending on the manufacturer, uses different keys or their combinations to enter. If there is no hint, then look at the instructions that came with the laptop. Or use 
After a successful login, our gaze will be presented with approximately the following window:
I must say right away that this window can be different for each manufacturer, even in the same brand, in different models, lines of laptops, there are different BIOSes. All settings and instructions are in English, so if you don't know it, use a translator to avoid unnecessary mistakes. Pay attention to the pointers at the bottom of the window, in some bios, they can be on the right side of the window. So: F1- Call for additional information, help. Esc- benefits from this catalog one level to the top, or an exit at all. Keys Select- this is navigation through tabs and transition from one line to another, usually these are navigation arrows on the keyboard or F6 and F5. F9- These are the default settings, that is, by default. For your changes to take effect, you must click F10, and then Enter... Now a little tabbed over so you have a general idea of what, where and why!
Main tab in BIOS menu
Here you have the ability to change the settings for the time and date. With its help, you can also do a rollback to extend the trial period of Windows 7, and sometimes even when fully charged with viruses, a rollback to the back date can help.
Advanced tab
So this is a tab with general BIOS settings, among which we can find:
- Virus Warning- Protection of the boot sector of the hard disk from any changes at the bios level.
- CPU Internal Cache- Enable and disable the first level cache.
- External Cache- The same thing, only the second level.
- Swap floppy seek- floppy disk drive for loading.
- HDD S.M.A.R.T. Capability- Enabling S.M.A.R.T. technology This option adds additional load to the system.
- Security Option- Indicates the area of action of BIOS passwords, it will only work when you enter the BIOS or when you log in and into the system.
- EzRestore- Disable and enable emergency system recovery for various problems.
- Video BIOS Shadow- When enabled, the options will greatly improve the performance of your system. Copying the BIOS code responsible for working with graphics into RAM.
Perhaps I did not specify all the parameters, but they may differ in their presence from your version of BIOS. If you have others and you do not know their purpose, write in the comments, we will figure it out together.
Security Option BIOS Tab
Setting a password, changing it, disabling it and the ability to specify the sphere of influence, for the BIOS only or for the entire system.
Power Option BIOS Tab
You can bet that in the event of an aircraft power failure, the computer will start itself. For home PCs, this is not relevant.
Boot Option BIOS Tab
Here we specify the order for system booting from certain media or drives. Even if you have specified, boot from a sidir or a flash drive, the system, if it is not there, will boot from the hard drive. Also, if there is an external bootloader, you must confirm the entrance from it by pressing any key.
About tab Exit I think it's not worth writing, it's a way out in Africa too :). Now in more detail about booting Windows, and specifying the priority for the media. In order to install Windoes on your computer, you first need to specify from where, from which media the system will be loaded, in our case it is a DVD. We start our PC, as soon as we see the prompt to enter the BIOS, as I wrote it, we immediately press the corresponding key. After a successful login, we need to enter the tab Advanced in some cases in a tab Boot. We have been provided with a list of possible download paths. 
Using the arrows or using the F6, F5 keys, select the desired option and press F10. That's all, with such simple manipulations, you indicated the path to boot the system from the right place. I will also write a little about the password setting function. So go to the Security tab, now briefly about its content.
- System password- the password that must be entered to turn on and boot the computer.
- Admin password or Setup password- the password that is put on the BIOS itself.
- Internal HDD Password- protection is put on the hard disk, while the disk itself is encrypted at the hardware level and cannot be read without a password, either on this or on another computer.
When you set a password, you need to enter it twice, so the risk of incorrect input is reduced. Pay special attention to this input, register and keystrokes, as this can lead to serious problems if you lose or forget your password. For laptop users, I will tell you about the problems that arise when you lose your password. It will not be possible to reset it by simply closing a jumper on the board. Although a reset is always possible, in the best case, you need "tricky" programs, and in the worst case, you need to unsolder the microcircuit with further flashing on the programmer. This will have to be done in service centers and the price will not please you in any way from $ 20 to $ 50, so think twice before installing something and be extremely careful.
Well, that's all I know and what I have shared with you. Of course, if you have problems and questions, I will be happy to help and sort out your problem together.
If you came to our site, then you, most likely, have seen this abbreviation of four Latin letters somewhere and wondered what BIOS is? If so, then we will try to briefly tell you about this concept.
When we turn on the computer, hardly any of us thinks that its performance is provided only by the programs contained in its electronic "brains". And not only those applications that we usually use every day, for example, editors, browsers, games, etc. Indeed, even the operating system itself, in which they operate, in fact, is a very large and complex program. But in order for it to work, a bridge is needed that would connect its functions with the capabilities of computer hardware.
The BIOS system serves as such a bridge. This abbreviation stands for Basic Input / Output System, which translated from English means "basic input-output system". Very often, however, the abbreviation BIOS is written in Cyrillic as BIOS. This is also a well-established name in Russian-language computer journalism, so in the article we will use it along with the traditional English abbreviation.
BIOS is a set of firmware that provides basic functions for accessing the hardware capabilities of a computer, no matter whether it is a stationary desktop or laptop. The BIOS is the foundation upon which all other computer software, including operating systems and application programs, is based. Although the most complex operating systems, such as Windows, are now able to access the hardware of a computer, bypassing the standard features of the BIOS, nevertheless, the importance of the BIOS as a link between hardware and software is still great. In addition, at the boot stage, no operating system can do without the tools provided by BIOS.
A bit of history
Most of the personal computers that we are used to using belong to the IBM PC family. This architecture was developed by IBM in the early 80s. At that time, there were three major manufacturers of BIOS firmware for the PC architecture:
- Phoenix Systems
- Award
And until now, the BIOS developments of these companies are used most often.
It should be borne in mind, however, that although computer devices belonging to some other architecture also use systems like BIOS, they are called differently. Thus, the term BIOS can be correctly used only to refer to the basic input / output system in computer systems with the IBM architecture. The first BIOS analog appeared back in 1975 in the CP / M operating system, designed to work on computers with Intel processors.
I don’t know about you, but for me the process of turning on and loading the computer is a kind of sacred action, even if it has become a routine procedure due to its frequency. The process of reviving the soulless "iron" of microcircuits and turning it into a work and entertainment unit obedient to the will of a person is akin to some kind of magic.
And this truly magical process begins this very BIOS system. It is quite small - the size of the permanent memory occupied by it is only about 1 MB, which is quite a bit by today's computer times, operating in such units of information as gigabytes and terabytes.
Perhaps the most important function of the BIOS, which it begins to perform immediately after the computer is connected to the network, is to check the health of the entire hardware of the computer. This verification procedure is called the POST procedure. If the health check of one of the components of the computer fails, then the BIOS informs the user that something is wrong. A message can be displayed on the monitor screen, but in case something is wrong with the computer's video system itself, the BIOS, in addition, gives a number of sound signals, which can be used to judge the nature of the malfunction. In addition to checking the computer when loading, the BIOS is also looking for special ROM modules that expand the capabilities of the computer.
After checking the devices for operability, the BIOS sets low-level operating parameters for each of them. If the test is successful, then control of the computer is transferred to the operating system (of course, if it is installed on any available media).
Other BIOS functions
The second, no less important function of the BIOS is the storage of information about the hardware characteristics of the computer, as well as user settings, with the help of which the owner of the computer or the system administrator can optimize the performance of its hardware. This is the incarnation of BIOS that is most often encountered by an ordinary user.
I mean, for sure, the BIOS settings interface well known to most readers, the so-called BIOS Setup, which can be accessed during computer or laptop boot by pressing a certain key (usually Delete) on the keyboard. Many users believe that, in fact, the BIOS is this very interface, but in fact it is only a means of communication between the BIOS and users. In the BIOS settings interface, you can set many parameters for the operation of various computer subsystems - the processor, sets of chipsets on the motherboard, memory, video cards, controllers, buses, hard drives and floppy drives. Very often, these parameters are used to "overclock" hardware devices such as the processor, RAM, and video card. In practice, however, an ordinary user who is not particularly experienced in the intricacies of optimizing computer hardware is most interested in such parameters as setting the system time and date, as well as the priority of choosing boot devices. Other parameters are hardly worth touching if you do not exactly understand their purpose, otherwise your computer or laptop may simply become non-functional.
And finally, by no means the least important task of the BIOS is to provide access to various devices from the side of application programs. As a matter of fact, this BIOS hypostasis was the function for which it was originally developed. This is even indicated by its very name - "basic input-output system". The BIOS contains drivers for standard I / O devices, as well as a special software interface (interrupt system), which provides device control and access at a basic level to the processor, I / O ports, controllers, video system and disk drives. By the way, many computer devices also contain their own BIOS, but this article means only the BIOS that is located on the motherboard, since its functions are most important for the average user.
The newest BIOS versions also contain a special SLIC data table, which contains information about the licensed software.
BIOS hardware features
Like any program, the BIOS must be written somewhere and stored somewhere. This place is a special microcircuit on the motherboard. A special battery is used to power the BIOS chips. Previously, the BIOS was hardwired into ROM (read-only memory of a computer), and it was impossible to change it if necessary. Of course, this situation did not suit many - both computer manufacturers and end users. Therefore, now in most modern motherboards, in the event of new BIOS versions being released, it is enough just to update the BIOS version located in a special rewritable CMOS memory. This type of memory is characterized by low power consumption, due to which the information contained in the BIOS can be stored for an extremely long time. And there can be a lot of reasons for updating BIOS versions - from detecting errors to the need to introduce any new functions or add support for new equipment.
In some BIOS versions, you can also find a number of built-in utilities that can compete in their capabilities with similar applications - for example, checking and formatting a disk. There are even antiviruses and browsers built into BIOS.
The future of BIOS
BIOS, like any computer technology, is constantly evolving. New, previously unused functions are introduced into it, and many old ones disappear. Even new technologies are proposed (and not just offered, but are already widely used) that should replace the traditional BIOS, for example, EFI (Extensible Firmware Interface) technology. Nevertheless, this technology is not yet widely used and the traditional BIOS still does not give up its positions.
Conclusion
As a conclusion, let us list once again the main functions that the BIOS performs in a computer or laptop:
- Checking the performance of the motherboard and computer peripherals;
- Preparing the computer for loading the operating system;
- Providing programs with basic means of accessing hardware devices;
- Storage of equipment settings data and the ability to change these parameters.
So, if you used to be scared of the very abbreviation BIOS, then most likely this is already in the past. It is important for the end user to understand that BIOS is a special low-level software shell, on which the operation of higher-level programs is based, and its correct setting, as well as timely updating, can improve the performance of a computer or laptop.
BIOS (Basic Input / Output System - basic input / output system) is a program for initially starting up a computer, setting up hardware, and providing I / O functions. The BIOS setup utility 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 BIOS, but this is not entirely correct, since Bios Setup is one of the components of the BIOS.
BIOS performs the following main functions.
Performs a self-test of iron when the supply voltage is turned on, while starting the program computer self-test at power on (Power On Self Test - POST).
It initializes input-output devices (IO)... Part of the initialization is performed precisely by hardware and software, which are integrated into the air-blast adapters.
Provides RAM loading and executes the program BOOT - OS bootloader.
Handles software interrupts from an I / O device and serves their functions. For all standard peripherals, the BIOS stores a service program. Some of which are loaded separately and are also stored in a separate area of disk storage.
Provides a configuration setting for a computer. 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 the hardware components of the PC with the OS when it is loaded and using driver software.
BIOS Flash stores software as a “hard product” - Firmware. Unlike Software, the code of this type of software is permanently stored on the computer, so that for automatic activation of BIOS programs, it is enough to simply turn on the power of the computer. BIOS contains programs of the following types.
The equipment self-test program when the supply voltage is turned on - POST.
BIOS expansion programs. In parallel with self-testing, the program of initialization (programming) of the registers of the I / O controllers and adapters is launched. Some checks, not included in older BIOS versions, can be performed by extending it on the I / O adapter cards.
Operating system boot program. Initialization is completed by transferring control to the boot loader of the operating system - BOOT.
Routines for handling interrupts from the I / O.
Function service routines. For each standard peripheral device in flash BIOS the maintenance routine is stored.
Driver programs designed for the interaction of the OS and hardware during system boot.
Computer Configuration Utility - Setup.
Initialization and testing of computer nodes.
Each time you turn on the power of a computer such as an IBM PC (or compatible) and before starting the operating system, the computer's processor performs a BIOS procedure called Power On Self Test (POST). The same procedure is also performed when you press the RESET button or the Ctrl-Alt-Del key combination. The main purpose of the POST procedure is to test the basic functions and subsystems of the computer (such as memory, processor, motherboard, video controller, keyboard, floppy and hard disks, etc.) before loading the operating system. This to some extent insures the user against 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 decrease in the time interval from the moment the PC is turned on to the start 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, I think, too: it is 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 consider the possibilities it provides for computer repair.
Before starting each of the tests, the POST procedure generates the so-called POST code, which is displayed at a specific address in the address space of the computer's input / output devices. If a malfunction is detected in the tested device, the POST procedure simply "hangs", and the previously displayed POST code unambiguously determines on which of the tests the "hang" occurred. Thus, the depth and accuracy of diagnostics using POST codes is completely determined by the depth and accuracy of tests of the corresponding POST BIOS 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 back in the IBM PC / XT with an eight-bit ISA system bus, historically it so happened that POST codes are only one byte, which is given in the POST code tables as one-bit hexadecimal numbers in the range 00h-FFh (0- 255 decimal). It should be noted that the POST code tables are different for different BIOS manufacturers and, due to the appearance of new tested devices and chipsets, they 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 manuals for motherboards (for example, (See the P6SBA-P6DBS Supermicro Boards Manuals).
To display POST codes in a human-friendly form, devices called POST Cards are used. POST Card is a regular computer expansion card that can be inserted (when the power is off!) Into any free (corresponding to its connector - ISA or PCI) slot and has two seven-segment LEDs for displaying POST codes. Previously, before the PC 99 and PC 99A specifications, the POST Card for the ISA bus was the most common. Now, in connection with the threat of the complete elimination of the ISA bus, more expensive POST Cards for the PCI bus have begun to appear. For notebooks that do not have ISA and PCI buses at all, POST Сard are issued, designed to be installed in the LPT port. It should be noted that for such a POST Card to work, appropriate support from the BIOS "a notebook is required.
Rice1. POST Cardfor
tiresISA.Author's version.
The simplest POST Card for the ISA bus from the manufacturer noname displays POST codes at a fixed address of 80h and does not have switches to change this address. The passage of the computer's RESET signal to such a POST Card is fixed by the blinking of the points of the seven-segment indicator of POST codes or is displayed on it with special symbols. More expensive POST Cards have switches for selecting the address of the port of POST codes, 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 POST Card for connecting to the LPT connector of laptops - MICRO POST. Very interesting is the original POST-Probe PCI from Micro2000, Inc (http://www.micro2000.com), on two adjacent sides of which there are connectors for PCI and ISA buses 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 Cards (MiniPOST) and more complex ones - PocketPOST. However, a real professional tool is PHD 16 for ISA (Professional Hardware Diagnostics) by Ultra-X, Inc. PHD 16 has two modes of operation: diagnostics and POST codes, which are selected by setting the appropriate jumpers. In the POST mode, the codes generated by the POST system are simply displayed on a two-digit seven-segment indicator PHD 16. The diagnostic mode is divided into a training mode - a long run of tests to detect floating errors and a mode of finding and eliminating serious damage to completely "dead" systems, in which the standard BIOS of the motherboard replaced with ROM BIOS Ultra-X with a dedicated set of advanced tests. As new motherboard chipsets are released, updated ROM BIOS Ultra-X 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 properly, on the computer monitor. The more modern PHD PCI from Ultra-X, Inc is designed for the PCI bus and, unlike PHD 16, does not need an external video adapter, since it has a built-in standard SVGA video output for displaying test results on a monitor.
In order to better understand how to use the POST Card, consider a typical sequence of tests performed by the POST procedure:
Processor testing.
Checking the checksum of the ROM BIOS.
Check and initialize DMA controllers, IRQ and 8254 timer. After this stage, sound diagnostics become available.
Checking memory regeneration operations.
Testing the first 64 KB of memory.
Video controller initialization. After this stage, diagnostic messages are displayed on the screen.
Testing the full amount of RAM.
Testing the keyboard.
Testing CMOS memory.
Initialization of COM and LPT ports.
FDD controller initialization and test.
HDD controller initialization and test.
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); in case of failure - system shutdown (HALT).
Before testing a computer using a POST Card, you need to determine the BIOS manufacturer of the motherboard: this can be done either by the sticker on the BIOS chip, or by the inscriptions displayed on the screen by a similar working motherboard. Then you should find the corresponding POST code table for this BIOS: AMI - http://www.ami.com, AWARD - http://www.award.com.
The sequence of steps for repairing a computer using the POST Card is as follows:
We turn off the power of the faulty computer.
Install the POST Card into any free slot on the motherboard.
We turn on the computer power 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 encountered problems and comprehend the probable causes.
When the power is off, we rearrange jumpers, loops, memory modules and other components in order to eliminate malfunctions.
We repeat points 3,4,5, achieving a stable POST procedure and the start of loading the operating system.
Using software utilities, we perform final testing of hardware components, and in case of floating errors, we carry out a long run of the corresponding software tests.
When repairing a computer without using POST Card, points 2-4 of this sequence are simply omitted, and from the outside, repairing a computer looks just like a feverish rearrangement of jumpers, memory, processor, expansion cards, power supply, and, to top it off, the motherboard. If large firms have a large stock of serviceable components, then for small firms and individuals repairing a computer by installing known serviceable components turns into a complex problem. It is even more difficult for service engineers who promptly leave for the customer and are forced to take with them a whole suitcase of spare parts. It happens that the replacement of computer components for the bewildered questions of the client takes 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 repair carried out 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 symbols or by a 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 connected to the power supply with the processor and POST Card installed.
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 loops (especially often the IDE loop is inserted upside down). By sequentially inserting memory, video adapter, and then other cards, and observing the POST codes on the indicator, they find a faulty module. In case of faulty memory for computers with AMI BIOS, the POST code sequence usually stops at code d4 (for old 386/486 boards - at code 13); with AWARD BIOS - on codes C1 or C6. It happens that in this case it is not the memory itself that is faulty, but, for example, the motherboard - the reason lies in poor contact in the SIMM / DIMM connectors (the contacts are bent / closed), or the memory itself is not fully inserted into the connector.
If the video adapter for computers with AMI BIOS is faulty, the POST code sequence stops at codes 2C, 40 or 2A, depending on the BIOS modification, or skips these codes without the corresponding video card initialization strings appearing on the monitor (indicating the type, memory size and 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 other cards one by one and connecting the cables, based on the readings of the POST Card indicator, they determine which of the components pushes the system bus and prevents the computer from booting.
Let us now return to the case when the initial system reset does not even pass (on the POST Card indicator at the very beginning of the test, no special symbols appear 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 working 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 that consists only of the motherboard, processor, POST Card and power supply. If the motherboard is completely new, then the reason usually lies in the incorrectly set jumper for selecting the frequency / multiplication / processor type, sometimes - the incorrectly set Clear / Normal CMOS jumper. Very often, the reason for inoperability is the processor undershooting to the stop in Slot 1 or the inverted position of the 486 processor. At the same time, if power is supplied to a 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, together with a good response from the engineer and a quick power outage, has already saved the lives of more than one processor and motherboard.
If all jumpers and the processor are installed correctly, and 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 faulty (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 computer testing 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 more readable than counting the duration and number of computer beeps. We can say that the POST Card is the eyes and ears of a computer repair engineer.
Who can use a POST Card? First of all, service engineers, computer assemblers, salesmen in a computer store, system administrators - everyone who has to solve problems with computers in a short time. The POST Card is also irreplaceable for professional motherboard repairmen who fully use the diagnostic capabilities of the POST BIOS procedure. Even convinced skeptics, after solving problems one or two times with the help of the POST Card, could no longer part with it, grabbing it in difficult cases, like a drowning man grabbing a straw. And, finally, there is an unconventional use of POST Сard by programmers who are very far from hardware problems. Since the POST Card indicator displays the state of the POST code port, programmers, when debugging additional BIOS modules or programs of an industrial stand-alone control computer without a monitor, can track the checkpoints of their program using the POST Card indicator by simply entering conditional codes into the POST codes register. For example, when programming in Turbo Pascal, in order to display the number 5Ah on the POST Card indicator operating at 80h, you can use the operator:
port [$ 80]: = $ 5A;
And finally, anticipating the questions about where can you get the POST Card? Industrial manufacturers of POST Card classify equipment for repairing computers as professional, therefore, if you have an amount of $ 100-150 (and for PHD PCI, the price reaches $ 1000), you can order a POST Card on the websites of the above manufacturers. The second way out of this situation is to independently assemble the simplest POST Card for the ISA bus. Such a POST Card with a binary error indicator on 8 LEDs contains 4 widely available K555 (74LS) series ICs and can be produced even by a novice radio amateur in 1-2 pm, and the production cost is minimal.
The ISA bus is still quite popular, especially considering the fact that the simplest POST Card proposed for production will serve to repair a large number of existing computers with the ISA bus. It is worth paying attention to the fact that many newer motherboards with the I820 chipset have one ISA slot. Therefore, I think the simplest POST Card for the ISA bus will find use for at least another 2-3 years. In addition, the implementation of the 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.
A diagram 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 contacts of the ISA connector. On microcircuits DD2, DD3, DD4 there is a decoder of the output device address with a fixed address of 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 with 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 bottom part with an ISA connector cut off from an 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 installing discrete elements. The design can use microcircuits DD1 type K555IR23, DD2-K555LA2, DD3,4 - K555LE1, as well as their counterparts from the K1533, K1531, K531 series (foreign 74LS, 74ALS, 74HC, 74F). The HL0-HL7 LEDs must be arranged 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: a lit LED corresponds to a logical 1, an off - 0. To convert the resulting binary code into a two-digit hexadecimal form, adopted in the POST code tables, it is necessary to mentally divide the HL7 ... HL0 LEDs into two halves: (HL7, HL6, HL5, HL4) and low (HL3, HL2, HL1, HL0), then, according to table 1, determine your hexadecimal character for each half and mentally combine these characters in the correct order: the high half corresponds to the high character, and the low - younger. With some practice, this whole procedure can be done in the mind.
|
Senior half HL7 HL6 HL5 HL4 |
Hexadecimal code of the upper half |
Younger half HL3 HL2 HL1 HL0 |
Hexadecimal code of the younger half |
Result POST Code |
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 in the 00h-FFh range into the output device at address 080h, and you need to make sure that the POST Card indicator readings correspond to the data displayed on port 080h. You can get such a program here: posttest.zip(4 KB), in addition, it can be used for learning and training in translating POST codes from binary to hexadecimal.
What improvements can you suggest for the simplest POST Card? First of all, it is advisable to add register DD5 (K555TM2) with LED HL8 to fix the passage of the RESET signal (diagram 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 malfunction 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 ( picture 2) in this case will display random garbage, which will be written to the DD1 register every time the power is turned on. This garbage can be misinterpreted as some kind of POST code. If you set additional register DD5 ( picture 3), then when the RESET signal arrives and before the first POST code is written to the DD1 IC, all the HL0-HL1 POST codes will be extinguished by a high level at pin 1 of DD1. In addition, by the short flashing of the HL8 LED, it will be possible to judge the passage of the RESET signal.
As a second improvement, it is possible to 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 ICs for converting a full four-bit binary code into a seven-segment code, but they can be replaced, for example, with programmable ICs. Schemes of the simplest seven-segment decoders, together with firmware on the K155PE3, were published in the magazine "Radio" (for example, "Radio" N 12, 1987, page 55). With some redundancy, the more affordable K573RF2 UVRPROM ICs can also be used as a decoder (6). However, even the simplest POST Card with displaying POST codes in binary form on 8 LEDs will significantly reduce the time for troubleshooting and, I hope, will make life much easier for many computer assemblers / repairers!
You've heard about BIOS, its errors or motherboards with dual BIOS, but it's almost impossible to figure out these terms on your own.
The abbreviation sounds strange. Therefore, to answer what it is, what is its role, why it is needed and to get many other useful information, this guide was created.
What is bios
It is the first level software - the first program that starts when you turn on your computer, laptop, tablet, and so on.
In order to better understand that this software is the first, you should know that the programs installed on your system, such as a browser, media player or office suite, are the latest programs.
The operating system is the middle tier because the drivers interact with the system resources and the BIOS directly controls the hardware.
It provides certain services that enable users to customize and receive information from programs and top-level components.
For example, a user, through installed programs, can find out the rotational speed of the fans that are on the computer or from the temperature of various components, including the processor and video card.
How bios works and how to interact with it
Bios is a relatively small program, with a maximum size of 16 MB. Modern BIOS systems are equipped with a user interface in which the user can configure the hardware parameters, set the current time and other minor settings, such as the boot order of storage devices.
Most modern motherboards offer several options for settings, for example, changing the frequency or voltage of the processor, shared memory between the processor and video card, RAM, and others.
Configuring BIOS is complex and can be dangerous, if the user does not know the exact effect of each parameter, then he can choose the wrong values for the components, which have a number of restrictions.
For example, setting the processor to a very high frequency can cause the processor to overheat, thereby causing the computer to run non-stop.
To ensure that the changes you make are safe, make sure you are familiar with the hardware settings you want to change.
Another parameter related to BIOS is saving settings when the system (computer or laptop) is turned off.
To do this, the BIOS has a small CMOS memory capacity, which is powered by a battery, as in the image below.
When it comes to computers, CMOS is the memory chip that stores the settings of your computer hardware.
If the CMOS battery is discharged, then the BIOS will use the default settings, and not those set by the user.
Why do you need a bios
The most important task for which the BIOS is responsible, when you press the power button, turn on the computer or laptop, start the fans, check the voltage levels in the system, run several tests to assess the state of system components, and then load the drivers and start the operating system boot process.
If any errors occur during this process, the BIOS will display a message informing that something went wrong. In the picture below you can see an example of a possible error.
Before the BIOS was invented in 1975, the operating system was the first program to run at system startup.
This meant that the computer could only run one operating system that was built in. In addition, if the operating system crashed, the entire computer would become unusable.
The use of BIOS provides additional flexibility, allowing users to install any operating system they want or restore the current one in case of errors.
What is Dual BIOS
The BIOS on the board has a memory chip. You can see this chip in the image below.
Dual technology is equipped with two chips - main and backup. If the main memory chip is damaged, the BIOS will not be able to boot. Therefore, some manufacturers use dual chips.
If the main BIOS is damaged, restart the computer and the backup microcircuit will be used to boot the system.
What is UEFI
UEFI is a program that can be seen as a modern and powerful BIOS.
It plays the same role as the BIOS, but has some advantages such as encryption, remote diagnostics and computer repair, even if no operating system is installed.
UEFI became popular after the release of Windows 8, as it was the first operating system with a large number of users to be offered native UEFI support.
Like any traditional BIOS, UEFI is configured by the manufacturer of the motherboard you are using.
In the case of tablets and laptops, a small number of settings will be displayed in UEFI. In the picture below, you can see how it is on Microsoft's Surface Pro 2 tablet.
For computers, UEFI has more settings than the standard one.
Conclusion
As you can see by reading this article, a BIOS is a fundamental component of any computer, and knowing how to use it can provide more flexibility and performance.
More advanced users and IT professionals can use it to get the most reliable performance possible for a specific computer or device.
If you are not an expert, then the default settings will suit the general needs of users and your system will work as expected.
Hope this tutorial was helpful. If you have questions or some ideas, feel free to use the comments section below. Good luck.
