BIOS and UEFI

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Firmware is specialized program code stored in flash memory.

• distinct from software because it is very closely tied to the basic functions of a specific hardware device type and model
• firmware provides low-level code to allow PC components installed on a particular motherboard to be initialized so that they can load the main operating system software
• legacy firmware for a PC was a type called the Basic Input/Output System (BIOS)
• Newer motherboards may use a different kind of firmware called Unified Extensible Firmware Interface (UEFI)
  • provides support for
    • 64-bit CPU operation at boot
    • full GUI and mouse operation at boot
    • networking functionality at boot
    • better boot security
  • may also support booting in a legacy BIOS mode
• System settings can be configured via the system firmware setup program
  • system setup program is accessed via a keystroke during the power-on (boot) process, typically when the PC vendor’s logo is displayed
  • key combination used will vary from system to system
    • typical examples are Esc , Del , F1 , F2 , F10 , or F12

Tip

• One issue with modern computers is that the boot process can be very quick
• you can Shift-click the Restart button from the Windows logon screen to access UEFI boot options

• You navigate a legacy BIOS setup program using the keyboard arrow keys
  • Pressing Esc generally returns to the previous screen
  • When closing setup, there will be an option to exit and discard changes or exit and save changes
    • Sometimes this is done with a key (Esc versus F10, for instance), but more often there is a prompt
    • option for reloading the default settings in case you want to discard any customizations you have made
• UEFI setup programs use a graphical interface and have mouse support
  • advanced menus may still require keyboard navigation