BIOS and UEFI are the firmware layers stored on the motherboard that run first when a computer starts. They test and initialize hardware, then load the bootloader. UEFI is the modern successor to legacy BIOS.
Why it matters
UEFI supports large disks via GPT, faster boot, a graphical setup menu, and security features such as Secure Boot. Legacy BIOS uses MBR partitions and a 2 TB boot disk limit.
You enter the setup screen with a key such as Del, F2 or Esc during startup to change boot order, enable virtualization, or adjust memory settings.
Example
$ [ -d /sys/firmware/efi ] && echo UEFI || echo Legacy BIOS
UEFIThis Linux check reveals which mode the current system booted in.
Common mistakes
- Installing an OS in legacy mode on a disk meant for UEFI, causing boot failure.
- Interrupting a firmware update, which can brick the board.
- Leaving virtualization disabled and then wondering why virtual machines fail.
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यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.