BIOS Why BIOS is used ?? BIOS is known as basic input & output system. Basic Definition:It is a program used by the processor of the computer to get the system started once it is turned on. Why BIOS is used ?? The main function of the BIOS is to manage the data flow between computer's operating system and attached devices like hard disk,keyboard,mouse and etc. It is a type of firmware used by the processor during the booting process.

FIRMWARE Firmware is a permanent software or program that is written in the ROM(Read Only memory) during the time of manufacturing. Firmware is a combination of both hardware and software The best example of a firmware is a remote control.

How is BIOS related to Booting process When you turn on the computer the operating system should be loaded in the main memory or the RAM(Random Access Memory). How is BIOS related to Booting process Once the operating system is loaded into the main memory or RAM(Booting process) is done,the BIOS takes charge of the computer's activity. The BIOS is stored in ROM(Read Only Memory) the secondary memory. The BIOS stored in the ROM chip attached to the motherboard is called as system BIOS.

FUNCTIONS OF BIOS POST: Test the computer hardware and make sure no errors exist before loading the operating system. Bootstrap Loader: Locate the operating system,if a capable operating system is located then the control is passed to it. BIOS Drivers: These are low level drivers that give computer basic operational control over your computer hardware. BIOS or CMOS Setup: It is a configuration program that allows you to configure hardware setting including system setting such as passwords,time & date.

FEATURES OF BIOS Every BIOS implementation is specifically designed for a particular type of motherboard model or particular computer. Originally,BIOS firmware was stored in the ROM memory but nowadays it is stored in Flash memory so that it can be rewritten without removing the chip from motherboard. The other reason for doing this is that,this allows easy updates of BIOS firmware,so new features can be added and bugs can be fixed. The latest advancement of BIOS is UEFI(Unified Extensible Firmware Interface).

KEY TERMS TO UNDERSTAND BIOS What is a Firmware ? What is Booting ? What is POST ? What is Bootstrap Loader ? What is BIOS drivers ? What is CMOS setup ? What is UEFI

Flow Chart of BIOS Functions   Turn on Computer Pass through POST Error Free NO Output to Monitor YES Plug’n’Play Pass through POST Error Free Test Boot Drive NO Pass through POST Error Free Bootable media found NO YES Pass through POST Error Free Load boot program Start operating system 7

Three kinds of BIOS software for Hardware devices 1. Permanent never changing BIOS for permanent hardware Stored on the ROM chip example-keyboard 2. Hardware that changes occasionally Requires extra volatile information so it must be stored on a separate chip called the CMOS example- RAM, hard drives, floppy drive 3. The other devices- 2 options BIOS is stored on the devices(example-sound card) Device drivers are installed to ensure communication between CPU and device 8

POST (Power On Self Test) Takes place right after you power on. Contains diagnostic routines for initializing the hardware and peripherals the video card, the main memory, the processor, the keyboard, etc. Checking their functions Error message on screen if an error is detected. If monitor cannot be detected, the beep codes are output by the system loud speaker. 9

POST (Power on self test) Beep codes A series of beep: BIOS program encounter problems One short beep: everything is normal Errors can be indicated when video screen does not function Interpret the beep codes by consulting main board menu POST Error messages Error messages are shown on display system Interpret error messages by consulting owner’s manual 10

BIOS and CMOS RAM Some people confuse BIOS with the CMOS RAM in a system. This confusion is aided by the fact that the Setup program in the BIOS is used to set and store the configuration settings in the CMOS RAM. They are, in fact, two totally separate components. The BIOS on the motherboard is stored in a fixed ROM chip. Also on the motherboard is a chip called the RTC/NVRAM chip, which stands for real-time clock/nonvolatile memory. Although it is called nonvolatile, it is actually volatile, meaning that without power, the time/date settings and the data in the RAM portion will, in fact, be erased. It is called nonvolatile because it is designed using complementary metal-oxide semiconductor (CMOS) technology, which results in a chip that runs on very little power. 4/27/2017 11 11

CMOS SETUP The floppy drive, hard drive, and the date/time settings can be changed using the standard CMOS setup Modern computers provide extra CMOS settings for memory management, password and booting options, error handling, and power management 12

Plug and Play Bios next looks for additional BIOS memory chips – might be on a Plug and Play card such as video card or a SCSI controller. If present, they run their routines and supplement or replace some functions of the system BIOS. If components no longer match the data stored in the CMOS (i.e. hardware change), message appears on screen to update. After all hardware components have been found and checked, Plug and Play goes to work. Interrupts and DMA channels of the plug-in cards in the ISA and PCI buses are queried and distributed. Onboard hardware, located on motherboard and in its ISA/PCI slots, are configured for operation. 13

Bootstrap Loader BIOS next accesses the first sector of the hard drive, termed the boot sector, and starts the “bootstrap loader” A small program that knows the file structure of the storage medium and can call the operating system’s start routine. Next, the operating system kernel is read into main memory and control of the hardware passes onto the operating system. 14

Configuring the BIOS BIOS settings are responsible for how the chipset is controlled. Chipset is the key to the overall system performance BIOS parameters: Choose the optimal bus speed settings Enable the CPU’s internal cache External cache memory Enable system BIOS shadowing Quick power-on self test Update the BIOS 15

What are the device drivers? Registry – Binary file that contains the configuration settings and device driver information • Control Panel – Applets that enable the configuration of a broad range of system devices • Device Manager – Used for changing or removing drivers for any particular device • REGEDIT and REGEDIT32 – Enables you to access and update the Registry directly 16 16

Things To Be Taken Care How to enter the BIOS 17

When you should update a PC's BIOS How to update the BIOS Identify the make and model of your motherboard. Find out the current BIOS version. Download the latest BIOS file. Updating in Windows. The update has failed – what now? Install a replacement BIOS chip Use the BIOS recovery feature (available on many systems with surface-mounted or soldered-in-place BIOS chips) 18

Back up your current BIOS code, if you can. Precautions to Take Before Updating a BIOS First, back up your data. Back up your current BIOS code, if you can. Record your hard drive configuration information. Record other nonstandard BIOS settings. Read carefully and completely the information provided with the flash BIOS download or chip-type BIOS update kit. Check to see whether your system has a write- protect setting jumper on the motherboard that must be adjusted to allow a BIOS update to take place. 19

How to Reset Your BIOS 3 Ways to Reset Your BIOS Resetting from Within BIOS Resetting the Jumper Removing the CMOS Battery 20

Configuration A modern BIOS setup utility has a menu-based user interface (UI) accessed by pressing a certain key on the keyboard when the PC starts. Usually the key is advertised for short time during the early startup, for example "Press F1 to enter CMOS setup". 21 21

Security An improperly executed or aborted BIOS update could render the computer or device unusable To avoid these situations, more recent BIOSes use a "boot block"; a portion of the BIOS which runs first and must be updated separately Some motherboards have a backup BIOS (sometimes referred to as DualBIOS boards) to recover from BIOS corruptions. Virus attacks may be there 22 22

Latest Updates As of 2011, the BIOS is being replaced by the more complex  Extensible Firmware Interface  (EFI) in many new machines The  Unified Extensible Firmware Interface  (UEFI) is a  specification  that defines a software  interface  between an  operating system  and platform  firmware UEFI can support remote diagnostics and repair of computers, even with no operating system installed The latest UEFI specification, version 2.5, was approved in April 2015. 23 23

UEFI 24 24

UEFI Advantages Ability to boot from large disks (over 2 TB- 9.4 ZB) Uses  GUID Partition Table  (GPT) unlike MBR in BIOS CPU-independent architecture and can support different platforms CPU-independent drivers Includes network capability Based on assembler as of C-language Network booting and Secure booting 25 25

UEFI Features Services EFI defines two types of services: Boot services  Boot services are available only while the firmware owns the platform (i.e., before the  Exit Boot Services call), and they include text and graphical consoles on various devices, and bus, block and file services. Runtime services Runtime services are still accessible while the operating system is running; they include services such as date, time etc. 26 26

UEFI booting Unlike BIOS, UEFI does not rely on a  boot sector, defining instead a  boot manager  as part of the UEFI specification. When a computer is powered on, the boot manager checks the boot configuration and, based on its settings, loads and executes the specified operating system loader or  operating system kernel. 27 27

FUTURE TRENDS-UEFI UEFI (Unified Extensible Firmware Interface) is a standard firmware interface for PCs, designed to replace BIOS (basic input/output system). 28

Future Trends of BIOS UEFI is the replacement for BIOS Unfortunately, BIOS design is quite outdated, carrying a number of limitations that are not acceptable in the current age of computing. UEFI is the replacement for BIOS, and it brings with it a host of modern functionality to carry PCs through the next few decades. It enables better disk support UEFI finally breaks free of the old DOS-style master boot record (MBR) disks taking us into the GUID partition table (GPT) future. GPT support at the firmware layer will allow disks of enormous size to be used, even for booting the operating system 29

Future Trends of BIOS(Cont.) Boot loaders are no longer needed UEFI takes the place of the traditional operating system boot loader, which relegates any boot loading tasks to be done within the operating system itself (like asking to boot in a Safe Mode). As a result, you have one fewer thing to break or make decisions about. It does not have to replace BIOS... UEFI can sit on top of the traditional BIOS and act as an interface between it and the operating system. Like BIOS, it presents a standardized view of the hardware to the operating system, allowing operating system makers to build on top of it and have their OSes work on a variety of motherboards. 30

Future Trends of BIOS(Cont.) It can use BIOS alternatives At the same time, UEFI acts as an abstraction layer between the firmware that acts as a BIOS and the operating system. This means that an equipment maker can use whatever it wants to in the role that the BIOS fills and put UEFI on top of it and an operating system that uses UEFI will work just fine. There is widespread industry support The UEFI standard enjoys a large amount of support within the industry already. The UEFI standards organization has companies like Intel, AMD, Apple, Microsoft, and a number of BIOS and motherboard makers on it. As a result, UEFI will be the way forward, not just some dead standard left in the industry's wake like so many other initiatives. Modern operating systems are all compatible with UEFI as well. 31

Future Trends of BIOS(Cont.) Your job won't change much Unless you are working as an embedded systems engineer or write low-level code for an operating system, UEFI probably won't affect your daily tasks. Sure, there are some IT roles that involve digging into the BIOS, but for the work they typically do, the differences between BIOS and UEFI will not make an impact on their work life. Apple already uses it Haven't heard of UEFI much? That's because while it is already in use, the most mainstream system out there using it is Apple, which isn't terribly friendly to tinkerers. It has also been used in Itanium systems for some time, as well as many embedded systems. 32

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