What is the difference between SeaBIOS (legacy BIOS) or OVMF (UEFI BIOS)?

[Helposoft Staff]

SeaBIOS (legacy BIOS) and OVMF (UEFI BIOS) are two types of firmware that can be used to initialize and start virtual machines. Here's a comparison of the two:

SeaBIOS (Legacy BIOS)​

1. Architecture:
   • Traditional BIOS, originally designed for IBM PC compatibles.
   • Uses interrupt calls to perform hardware initialization and bootstrapping.
2. Boot Process:
   • Simple and straightforward.
   • Boots from the first bootable device it finds.
3. Compatibility:
   • Broad compatibility with older operating systems and software.
   • Limited support for modern hardware features and large storage devices.
4. Limitations:
   • Cannot boot from disks larger than 2 TB.
   • No native support for modern features like Secure Boot or GPT (GUID Partition Table).

OVMF (UEFI BIOS)​

1. Architecture:
   • Modern firmware specification developed by Intel.
   • Replaces legacy BIOS with a more flexible and powerful system.
2. Boot Process:
   • Can boot from a wider range of devices and file systems.
   • Supports graphical user interfaces for pre-boot configuration.
3. Compatibility:
   • Better support for modern operating systems and hardware features.
   • Supports booting from disks larger than 2 TB, Secure Boot, and GPT.
4. Advanced Features:
   • Secure Boot: Ensures that only trusted software can boot.
   • Network booting (PXE) improvements.
   • More robust and flexible configuration options.

Summary:​

• SeaBIOS is suitable for older operating systems and environments where compatibility is a priority.
• OVMF (UEFI) is ideal for modern systems, offering advanced features, better security, and support for large storage devices.

Choosing between the two depends on the specific requirements of your virtual machine and the operating systems you plan to run. For most modern use cases, OVMF (UEFI BIOS) is recommended.