As a general rule, BIOS Setup program has character-based interface and is operated by a keyboard. There is a menu with the list of Setup basic program division in the main window of BIOS Setup. BIOS Setup menu bar usually resides in two columns; this variant is used in different versions of AwardBIOS (Phoenix-AwardBIOS) and AMIBIOS. The given interface is used in system boards of Gigabyte, MSI, Foxconn, ECS and many other manufacturers.
Another common variant of BIOS Setup interface is the one with the action bar in the top of the screen. Such interface is used in PhoenixBIOS, IntelBIOS as well as in some of AwardBIOS and AMIBIOS versions. This interface variant is used in ASUS, ASRock, Intel and some other system boards.
All the BIOS Setup divisions have similar structure.
The following control keys can be used in BIOS Setup program:
- ←, ↑, ↓, → (cursor control key) – divisions and parameters navigation;
- Enter – selected division entry, selected command execution or opening of popup window with the list of values of the selected parameter;
- Page Up/Page Down (or +/– on keyboard optional digital module) – change of the selected parameter’s value; it is possible to search through all the available values of the in-out parameter by pressing several times the mentioned above keys;
- Esc – exiting the division for the menu bar and if pressing in the menu bar – exiting BIOS Setup with undoing all the changes;
- F1 – help call for BIOS Setup operation;
- F2 – BIOS Setup colour palette change (not all the BIOS versions are provided with this parameter);
- F5 – previous values recovery for the selected division: the values will be returned that were set at the moment of entry to the Bios setup (this key is used for default settings installation in some BIOS versions);
- F6 – installation for the default settings selected division (Load Fail-Safe Defaults command); some other keys, for instance, F5 or F9 are used for these purposes in certain BIOS versions);
- F7 – installation for the selected division of optimised values (Load Optimized Defaults command);
- F10 – exit from BIOS Setup with all the changes saved; in this case it is necessary to confirm action by pressing Y and Enter keys.
The values of F1-F10 function keys can differ in certain BIOS versions, therefore it is preferable to check the system board manual or message in the screen bottom before use of these keys.
BIOS setup program can be called BIOS Setup Utility, CMOS Setup Utility or other. Abbreviated names of this program are often used, for instance, BIOS Setup or simply Setup. Sometimes, setup program is called nothing but “BIOS” but this is not quite correct because BIOS setup is merely one of the BIOS components. The term BIOS setup will be used throughout our articles.
To enter BIOS Setup you should press a designated key or their combination during initial computer testing. The most frequently used are Delete, less often F1 or F2; there are some other variants as well. To learn which key is fixed to BIOS setup entry is possible by reading the system board instruction or prompt message, which appears during POST procedure, and, for instance, has such a form as: Press DEL to enterSETUP.
If there is no board instruction and screen message is missing, you can try to use the most renowned variants in a successive order:
- one of the function key: Fl, F2, F3, F10,Fll, F12;
- Ctrl+Shift+S or Ctrl+Alt+S;
- Ctrl+Alt+Esc or Ctrl+Alt+Delete.
In addition to the fact that the key for BIOS setup entry should be known, it is also essential to choose the right time for its pressing – straightaway after the relevant screen message appearance. If a manufacturers’ logo is displayed instead of POST messages, try to press the entry key several times at 1.5-1 sec. intervals in Setup.
A box with the demand to enter password may come as a surprise to you during the first attempt of entering Setup. It means that a user who had worked with BIOS setup before your time password protect the entry.
In a majority of modern computers one of the basic BIOS versions is used.
- AwardBIOS of Award Software International Inc. (phoenix.com), the most well-known manufacturer of BIOS. AwardBIOS 4.51 was very popular in due time, AwardBIOS 6.0, which was widely distributed, appeared later. Award Inc. was acquired by Phoenix company in 1998, otherwise all the successive developments have been released under AwardBIOS or Phoenix-AwardBIOS trademark.
- AMIBIOS of American Megatrends Inc. (www.ami.com). AMIBIOS different modifications are used by a number of board leading manufacturers, for example ASUS, ASRock, MSI and others.
- PhoenixBIOS of Phoenix Technologies Ltd. (www.phoenix.com). It can be found on laptop computers and system boards of some manufacturers the most frequently. Phoenix Technologies Ltd. as it was already mentioned before owns Award Inc., and releases BIOS under the Award trademark. Sometimes BIOS versions can be found entirely developed by the system boards or laptops manufacturers: Intel, IBM, Toshiba, Dell and some other well-known companies. Such BIOS versions do not differ significantly from BIOS Award, AMI and Phoenix companies in their functions and interface.
In general, every model of system board requires personal BIOS version because it incorporates particular qualities of the usable chipset and peripherals. However, it is not profitable for the manufactures to spend time and resources on the full cycle of development their owned BIOS that is why BIOS launching is usually split into two stages.
- BIOS manufacturer (the most famous of which are AMI, Award and Phoenix) develops its basic version, where all functions, not dependent on the set of features of any given chipset, are implemented in.
- System board manufacturer up-grades basic version, taking account of particular board. In addition, BIOS code for the same model can be changed repeatedly by the time of board release. For example, it may be done for correction of the detected errors or addition of the new peripherals support.Consequently, “BIOS version” concept can be used to define:
- basic code BIOS version released by the specialist company: for instance, Award BIOS 6.0 – the sixth BIOS version of Award Software International Inc. which is used in many models of the system board. Otherwise, initial code for every system board can be updated with account for chipset and peripherals features;
- BIOS version for the system board’s particular model and various BIOS modifications or upgrades designed for the same model. The name of such BIOS version usually consists of board model abbreviated notation to which modification or update number is added. When BIOS setup program is being outlined, the term “BIOS version” implies BIOS version for the particular system board model.
The first device that starts up after pushing computer power button is PC power supply. If the supply voltages are in good working order, central processing unit will come into operation which reads out content of BIOS microcircuit and starts performing microcircuit-based Power-On Self Test or POST.
POST solves several basic problems.
1. Initializes and adjusts basic system composition: processor unit, chipset, internal memory and video display adapter.
2. Examines CMOS checksum and batteries’ condition. If the CMOS checksum is wrong, default values will be loaded.
3. Tests processor unit and internal memory. The testing results are usually displayed.
4. Initializes and adjusts hardware peripherals: keyboard, mouse pointing device, disk drive mechanisms, hard disks and others. Data about detected storage drives is usually displayed.
5. Distributes resources between peripherals and displays a datasheet with detected peripherals and appointed resources for them (Pic. 2.2).
Pic. 2.2. Final datasheet of POST procedure.
6. Searches and initializes peripherals from the BIOS.
7. Activates bootloader. When the successful POST procedure is accomplished, boot sector search, which can be located on the hard disk or removable media, starts. Peripherals inquest order is set with the help of parameters BIOS First Boot Device, Second Boot Device, Third Boot Device or related to them that are specified further.
Across the full range of modern computers BIOS is stored on the microcircuit on the basis of Flash Memory. Such microcircuit can be flashed with the assistance of specific programs outright on the computer. The record of the new BIOS version is usually called reflash. This operation may become necessary for addition of some new functions to the BIOS code, faults correction or replacing corrupted versions.
For most cases Flash Memory is installed on the specific board (pic. 2.1) that allows to replace the microcircuit easily when necessary.
Pic. 2.1. Examples of BIOS microcircuits installation on the mainboard.
BIOS microcircuits happened to be set on the rectangular case DIP32 (pic. 2.1, on the left) on the out-of-date computers; BIOS microcircuits on square case are used on majority of boards (pic. 2.1, in the middle), and tiny circuits with the serial interface can be found on the new boards (pic. 2.1, on the right).
Usually they are presented with the chip sticker with the reference to BIOS version. Otherwise, if there is no label – Flash Memory circuit marking is provided. BIOS uses configuration parameters which are stored in specific CMOS-memory. It received its name according to the technology of circuits manufacturing where Complementary Metal-Oxide Semiconductor was applied. CMOS-memory is energized from the specific battery set on the mainboard that is also used for energizing real-time clock.
BIOS (Basic Input/Output System) is a program for the initial boot of a computer, equipment adjustment and input/output functions support.
BIOS is recorded on the flash-memory microcircuit which is located on the mainboard. Initially, the main purpose of BIOS was input/output devices maintenance (keyboard, screen and disk drives); that is why it was called “Basic Input/Output System”. BIOS performs several functions in modern computers:
- boot and procedure of self-testing (Power-On Self Test, POST). A program, located in BIOS microcircuit, loads the first after computer power-up. It detects and examines the installed equipment, adjusts it and prepares for the future operation. If the equipment failure occurs, POST procedure will stop operating and corresponding message or alarm will be revealed;
- system parameters setting with the BIOS Setup program assistance. During the procedure POST equipment adjusts within the parameters that are stored in the specific CMOS-memory. Users can configure separate devices and entire system at their own discretion by violating these parameters which are edited in a special program called BIOS Setup or CMOS Setup. The majority of our articles will be dedicated to a system setup with the assistance of BIOS Setup program;
- input/output functions support with the assistance of BIOS program interrupts. System BIOS comprised of built-in functions for the manipulation with keyboard, video display adapter, disk drive mechanisms, hard disk drives, input-output ports, etc. These functions have been used in such operation systems as MS-DOS, and they are almost not used in Windows modern versions.