What is bios

Some computer owners who have only recently begun to master the world of computer technology may not even suspect that in addition to the operating system and various programs that can be used to work with (double-click - installation - start), there is also a whole area of partially available software codes. We are talking, of course, about the BIOS (BIOS).

Let's figure out what bios is. To make it more clear, let's start with an example. Imagine an abstract computer on which to download the Windows operating system. We plug the appropriate power cords into the sockets and press the power button on the system unit and ... nothing happens, because once we do not know what a bios is, it's not on the board. Think about where the computer can "know" that you need to start the download from the hard drive, and a certain one? After all, you can boot from a flash drive, CD, even on a local network. Why Winchester? Therefore, we can assume that somewhere in the computer there is some software mechanism that allows you to specify where to start the download.

The guess is correct! This really is. So we came to the question of what a bios is. On any motherboard there is a special microcircuit, into which a small control program is entered at the plant. Its functions, of course, are not limited to the choice of the boot device alone.

The work of the computer is as follows: all components are powered, their internal controllers perform self-tests and, if all is normal, set the readiness bit. Further, the control is transferred to the firmware located in the bios chip, it scans the bus for the presence of connected components and polls their state registers. The BIOS then configures IRQ interrupts and DMA channels for all connected components. Also, in accordance with the SPD, the delays of the RAM and chipset modules are set. By the way, CAS can be configured only at this stage, while the memory is not used. Now it became clearer, what is bios?

When problems are detected, the algorithm is interrupted and an error message is displayed (this may be an on-screen or encoded squeak of the system speaker).

The user can interfere with the BIOS, making adjustments: selecting memory latencies, disabling / activating many installed components, specifying the order of polling devices to boot the operating system. The changes made are saved due to the battery voltage on the board. The base part of the BIOS remains unchanged. To update it, you need to download from the manufacturer's site of the motherboard a special utility and the corresponding firmware. When flashing, the old program written in the chip is erased, and a new one is written in its place. By the way, to get into the BIOS settings of a personal computer, you need to press the Del button immediately after the system unit is turned on. After making the desired adjustments, do not forget to save them (option in the exit menu). Bios on the laptop performs the same functions. The only difference is that the settings are much smaller than for a full-fledged computer.

Screen captions that appear when you turn on - Award, Ami or Phoenix Technologies, indicate the types of bios. Although there are more of them, but these computers are most often used on computers. The principle of their work is the same. The difference lies in the different structure of the menu sections, the number of options available to the user, the implementation of the transfer of the download. Currently, the classical bios is gradually giving way to its ideological receiver - the UEFI system. In this innovation, many key features of the bios have been revised. In principle, the UEFI BIOS name can only be applied with reservations.