BIOS
['baios] n. shkurtesë nga basic input output system (BIOS) sistemi themelor për hyrje-dalje (informatikë)

What is BIOS?
BIOS is an acronym for Basic Input/Output System. It is the boot firmware program on a PC, and controls the computer from the time you start it up until the operating system takes over. When you turn on a PC, the BIOS first conducts a basic hardware check, called a Power-On Self Test (POST), to determine whether all of the attachments are present and working. Then it loads the operating system into your computer's random access memory, or RAM.
The BIOS also manages data flow between the computer's operating system and attached devices such as the hard disk, video card, keyboard, mouse, and printer.
The BIOS stores the date, the time, and your system configuration information in a battery-powered, non-volatile memory chip, called a CMOS (Complementary Metal Oxide Semiconductor) after its manufacturing process.
Although the BIOS is standardized and should rarely require updating, some older BIOS chips may not accommodate new hardware devices. Before the early 1990s, you couldn't update the BIOS without removing and replacing its ROM chip. Contemporary BIOS resides on memory chips such as flash chips or EEPROM (Electrically Erasable Programmable Read-Only Memory), so that you can update the BIOS yourself if necessary.
For detailed information about BIOS updates, visit:

What is firmware?
Firmware consists of programs installed semi-permanently into memory, using various types of programmable ROM chips, such as PROMS, EPROMs, EEPROMs, and flash chips.
Firmware is non-volatile, and will remain in memory after you turn the system off.
Often, the term firmware is used to refer specifically to boot firmware, which controls a computer from the time that it is turned on until the primary operating system has taken over. Boot firmware's main function is to initialize the hardware and then to boot (load and execute) the primary operating system. On PCs, the boot firmware is usually referred to as the BIOS.

What is the difference between memory and disk storage?
Memory and disk storage both refer to internal storage space in a computer.
The term memory usually means RAM (Random Access Memory). To refer to hard drive storage, the terms disk space or storage are usually used.
Typically, computers have much less memory than disk space, because RAM is much more expensive per megabyte than a hard disk. Today, a typical desktop computer might come with 512MB of RAM, and a 40 gigabyte hard disk.
Virtual memory is disk space that has been designated to act like RAM.
Computers also contain a small amount of ROM, or read-only memory, containing permanent or semi-permanent (firmware) instructions for checking hardware and starting up the computer. On a PC, this is called the BIOS.

What is RAM?
RAM stands for Random Access Memory. RAM provides space for your computer to read and write data to be accessed by the CPU (central processing unit). When people refer to a computer's memory, they usually mean its RAM.
New computers typically come with at least 256 megabytes (MB) of RAM installed, and can be upgraded to 512MB or even a gigabyte or more.
If you add more RAM to your computer, you reduce the number of times your CPU must read data from your hard disk. This usually allows your computer to work considerably faster, as RAM is many times faster than a hard disk.
RAM is volatile, so data stored in RAM stays there only as long as your computer is running. As soon as you turn the computer off, the data stored in RAM disappears.
When you turn your computer on again, your computer's boot firmware (called BIOS on a PC) uses instructions stored semi-permanently in ROM chips to read your operating system and related files from the disk and load them back into RAM.
Note: On a PC, different parts of RAM may be more or less easily accessible to programs. For example, cache RAM is made up of very high-speed RAM chips which sit between the CPU and main RAM, storing (i.e., caching) memory accesses by the CPU. Cache RAM helps to alleviate the gap between the speed of a CPU's megahertz rating and the ability of RAM to respond and deliver data. It reduces how often the CPU must wait for data from main memory.

What is ROM?
ROM is an acronym for Read-Only Memory. It refers to computer memory chips containing permanent or semi-permanent data. Unlike RAM, ROM is non-volatile; even after you turn off your computer, the contents of ROM will remain.
Almost every computer comes with a small amount of ROM containing the boot firmware. This consists of a few kilobytes of code that tell the computer what to do when it starts up, e.g., running hardware diagnostics and loading the operating system into RAM. On a PC, the boot firmware is called the BIOS.
Originally, ROM was actually read-only. To update the programs in ROM, you had to remove and physically replace your ROM chips. Contemporary versions of ROM allow some limited rewriting, so you can usually upgrade firmware such as the BIOS by using installation software. Rewritable ROM chips include PROMs (programmable read-only memory), EPROMs (erasable read-only memory), EEPROMs (electrically erasable programmable read-only memory), and a common variation of EEPROMs called flash memory.

What is an ACPI BIOS?
ACPI is an acronym that stands for Advanced Configuration and Power Interface, a power management specification developed by Intel, Microsoft, and Toshiba. ACPI support is built into Windows 98 and later operating systems. ACPI is designed to allow the operating system to control the amount of power provided to each device or peripheral attached to the computer system. This provides much more stable and efficient power management and makes it possible for the operating system to turn off selected devices, such as a monitor or CD-ROM drive, when they are not in use.
ACPI should help eliminate computer lockup on entering power saving or sleep mode. This will allow for improved power management, especially in portable computer systems where reducing power consumption is critical for extending battery life. ACPI also allows for the computer to be turned on and off by external devices, so that the touch of a mouse or the press of a key will "wake up" the computer. This new feature of ACPI, called OnNow, allows a computer to enter a sleep mode that uses very little power.
In addition to providing power management, ACPI also evolves the existing Plug and Play BIOS (PnP BIOS) to make adding and configuring new hardware devices easier. This includes support for legacy non-PnP devices and improved support for combining older devices with ACPI hardware, allowing both to work in a more efficient manner in the same computer system. The end result of this is to make the BIOS more PnP compatible.

What is CMOS?
CMOS, short for Complementary Metal Oxide Semiconductor, is a low-power, low-heat semiconductor technology used in contemporary microchips, especially useful for battery-powered devices. The specific technology is explained in detail at:
http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci213860,00.html
Most commonly, though, the term CMOS is used to refer to small battery-powered configuration chips on system boards of personal computers, where the BIOS stores the date, the time, and system configuration details.

How do I enter the Setup program in my BIOS?
Warning: Your BIOS Setup program is very powerful. An incorrect setting could cause your computer not to boot properly. You should make sure you understand what a setting does before you change it.
You can usually run Setup by pressing a special function key or key combination soon after turning on the computer, during its power-on self test (POST), before the operating system loads (or before the operating system's splash screen shows). During POST, the BIOS usually displays a prompt such as:
Press F2 to enter Setup
Many newer computers display a brief screen, usually black and white, with the computer manufacturer's logo during POST.
Entering the designated keystroke will take you into the BIOS Setup. Common keystrokes to enter the BIOS Setup are F1, F2, F10, and Del.
On some computers, such as some Gateway or Compaq computers, graphics appear during the POST, and the BIOS information is hidden. You must press Esc to make these graphics disappear. Your monitor will then display the correct keystroke to enter.
Note: If you press the key too early or too often, the BIOS may display an error message. To avoid this, wait about five seconds after turning the power on, and then press the key once or twice.

What's the difference between BIOS and CMOS?
Many people use the terms BIOS (basic input/output system) and CMOS (complementary metal oxide semiconductor) to refer to the same thing. Though they are related, they are distinct and separate components of a computer. The BIOS is the program that starts a computer up, and the CMOS is where the BIOS stores the date, time, and system configuration details it needs to start the computer.
The BIOS is a small program that controls the computer from the time it powers on until the time the operating system takes over. The BIOS is firmware, which means it cannot store variable data.
CMOS is a type of memory technology, but most people use the term to refer to the chip that stores variable data for startup. A computer's BIOS will initialize and control components like the floppy and hard drive controllers and the computer's hardware clock, but the specific parameters for startup and initializing components are stored in the CMOS.