1. Lesson Objectives Aims Key Words
Be able to describe the role and purpose of the BIOS
Understand the role of drivers in a computer system
Understand how virtual machines work and the need for virtualisation
Key Words

2. The boot process
Power on
Bios
Boot loader
Kernel / Drivers
Desktop

3. BIOS steps BIOS is loaded from ROM CPU begins executing instructions
Power on
BIOS is loaded from ROM
CPU begins executing instructions
POST
Power On Self Test
Scans for (enumerates) and initialises hardware
Looks for hardware changes
Performs basic tests (does not guarantee function)
Boot Loader
Selects the first boot device based on information collected in the POST.
Tries the boot loader of that device and, if successful, runs the OS.
Moves on to the next boot device if unsuccessful. Repeats until all boot devices have been tried.
If no boot devices have suitable boot loaders, the system will stop.

4. BIOS First widely used in the early 1980’s A 16 Bit system
Meaning processors have to
“emulate” 16 bit mode at power on!
Can only access 1mb RAM
Limited functionality
2TB disc limit
No support for security etc

5. The BIOS includes:
A configuration utility
Saved pointers to the location of boot devices in order of preference.
BIOS will attempt to read the boot sector (usually the first sector on a disc), if this is valid it usualy points to the boot loader which loads the operating system.

7. UEFI

8. UEFI An OS in its own right A “firmware” rather than BIOS
Extensible and modular
Support for secure boot
Support for absurdly large discs (billions of GB’s)
Easier integration with OS’s – change configurations without booting
Can access and store data in an EFI disc partition
Used by all new PC’s and Macs (since 2008)

9. VM’s
Computers are now incredibly well resourced
Sales of PC’s have fallen away, in part due to the fact there is no longer a 1-2 year upgrade need
This power brings with it the opportunity to consolidate hardware, especially in a server environment

10. Virtualisation: The emulation of generic PC hardware, through software
“Virtualised” systems believe they have sole access to the resources allocated to them
OS’s and software is installed exactly as normal
Generic drivers/hardware mean degraded performance in some application

11. Server side Machines can be:
Cloned
Multiple VM’s on one single physical machine
Managed separately
Repaired/maintained without affecting other services
Snapshotted – much easier recovery/backup
This makes greater use of hardware resources – rarely is a server at 100% load.

12. Drivers
Drivers are software that allow hardware resources to function with the operating system.
Why are drivers necessary?

13. Drivers
Allow operating systems to be “extended” to work with a wide ranger of peripherals
Responsibility on manufacturers to provide stable code and feature implementation
Removes OS complexity
Modularity

14. Review/Success Criteria
You should know:
The boot process in a PC
The purpose of the BIOS
Features of BIOS
The differences between BIOS and UEFI
The need for UEFI
What virtualisation is
Why it is useful in a server setting
What drivers are