The type of boot configuration chosen for a system greatly influences the selection of a
bootloader, its configuration, and the type of software and hardware found in the host. A
network boot configuration, for example, requires that the host provide some types of network
services to the target. In designing your system, you first need to identify the boot
configurations you are likely to use during development and in the final product. Then, you
need to choose a bootloader or a set of bootloaders that will cater to the different types of boot
setups you are likely to use. Not all bootloaders, for example, can boot kernels from disk
devices. In the following, I will cover the possible boot configurations. Let us start,
nevertheless, by reviewing some boot basics.
All CPUs fetch their first instruction from an address preassigned by their manufacturer. Any
system built using a CPU has one form or another of solid state storage device at that location.
Traditionally, the storage device was a masked ROM, but flash chips are increasingly the norm
today.[3] The software on this storage device is responsible for bootstrapping the system. The
level of sophistication of the boot software and the extent to which it is subsequently used as
part of the system's operation greatly depends on the type of system involved.
[3] Masked ROMs continue to be used when devices are produced in very large quantities. Consumer gaming
devices such as consoles, for example, often use masked ROMs.
On most workstations and servers, the boot software is responsible only for loading the
operating system from disk and for providing basic hardware configuration options to the
operator. In contrast, there are very few agreed upon purposes, if any, for boot software in
embedded systems because of the diversity in purposes of embedded applications.
Sometimes, the boot software will be the very software that runs throughout the system's
lifetime. The boot software may also be a simple monitor that loads the rest of the system
software. Such monitors can then provide enhanced debugging and upgrading facilities. The
boot software may even load additional bootloaders, as is often the case with x86 PCs.
Embedded Linux systems are as diverse as their non-Linux counterparts. Embedded Linux
systems are characterized, nevertheless, by the requirement to load a Linux kernel and its
designated root filesystem. How these are loaded and operated, as we'll see, largely depends
on the system's requirements and, sometimes, on the state of its development.
There are three different setups used to bootstrap an embedded Linux system: the solid state
storage media setup, the disk setup, and the network setup. Each setup has its own typical
configurations and uses.
bootloader, its configuration, and the type of software and hardware found in the host. A
network boot configuration, for example, requires that the host provide some types of network
services to the target. In designing your system, you first need to identify the boot
configurations you are likely to use during development and in the final product. Then, you
need to choose a bootloader or a set of bootloaders that will cater to the different types of boot
setups you are likely to use. Not all bootloaders, for example, can boot kernels from disk
devices. In the following, I will cover the possible boot configurations. Let us start,
nevertheless, by reviewing some boot basics.
All CPUs fetch their first instruction from an address preassigned by their manufacturer. Any
system built using a CPU has one form or another of solid state storage device at that location.
Traditionally, the storage device was a masked ROM, but flash chips are increasingly the norm
today.[3] The software on this storage device is responsible for bootstrapping the system. The
level of sophistication of the boot software and the extent to which it is subsequently used as
part of the system's operation greatly depends on the type of system involved.
[3] Masked ROMs continue to be used when devices are produced in very large quantities. Consumer gaming
devices such as consoles, for example, often use masked ROMs.
On most workstations and servers, the boot software is responsible only for loading the
operating system from disk and for providing basic hardware configuration options to the
operator. In contrast, there are very few agreed upon purposes, if any, for boot software in
embedded systems because of the diversity in purposes of embedded applications.
Sometimes, the boot software will be the very software that runs throughout the system's
lifetime. The boot software may also be a simple monitor that loads the rest of the system
software. Such monitors can then provide enhanced debugging and upgrading facilities. The
boot software may even load additional bootloaders, as is often the case with x86 PCs.
Embedded Linux systems are as diverse as their non-Linux counterparts. Embedded Linux
systems are characterized, nevertheless, by the requirement to load a Linux kernel and its
designated root filesystem. How these are loaded and operated, as we'll see, largely depends
on the system's requirements and, sometimes, on the state of its development.
There are three different setups used to bootstrap an embedded Linux system: the solid state
storage media setup, the disk setup, and the network setup. Each setup has its own typical
configurations and uses.
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