Bootloader Overview

• Bootstrapping
– When system is powered on, the first piece of code (called bootstrapping)
initializes basic hardware and then bring up OS kernel.
– It can be included in a bootloader, or in OS directly.
• Bootloader Selection
– The Processor architectures and platforms that it supports
– The OS that it supports
– Debugging abilities, Stability and Portability
– Functionalities:
• simple bootup, or with monitoring capability and lots of drivers support.
– The medium they are installed in
• usually ROM, EEPROM or Flash
– The storage device from which the kernel image is downloaded
• host PC, local Flash, disk, CF, etc.
– The device and protocol by which the kernel image is transmitted
• Serial port, USB, ethernet, IDE, etc.
– The 'host-side' software used to transmit the kernel image
• if it is coming from an external device/machine.
– 'sleep' reset support
• Not to do a normal reboot if this was a sleep wakeup.