EMBEDDED LINUX ARCHITECTURE

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EMBEDDED LINUX ARCHITECTURE
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EMBEDDED LINUX ARCHITECTURE

• Architecture of Embedded Linux
• Linux Kernel Architecture

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded Linux

• The Linux operating system is Monolithic.
• Flavors of Oss
• Real-time Executives
• Monolithic
• Microkernel

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded LinuxReal-time Executives

• Traditional Real time Executives are made for
  MMU-Less processors.
• They are real-time in nature because there is no
  overhead of System Calls , message passing or
  copying of Data.
• All Software running on system should be
  Foolproof.

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded LinuxReal-time Executives (cont.)

• Adding New Software becomes a not-so-pleasant
  action.
• It is also very difficult to add applications or
  kernel modules dynamically.
• As the prices of memory , flash and computing
  power are decreased , the ability to upload more
  software increased.

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded LinuxReal-time Executives (cont.)

• Overtime in Embedded market The software too
  started becoming the differentiating factor in
  selling the embedded systems.
• RTEs were suited for Large-Scale software
  Integration.
• Alternative Models Emerged
• Monolithic And Micro-Kernel
• suited for processors having MMU.
• The Linux derivative uClinux runs on the MMU-less
  processors provides flat address space

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded LinuxReal-time Executives (cont.)
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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded LinuxMONOLITHIC KERNELS

• Monolithic kernels have a distinction between the
  user and kernel space.
• Monolithic Kernels can support a large
• application software base.
• Applications can be added to a live system
  without bringing down the system.

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded LinuxMONOLITHIC KERNELS
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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded Linux MICRO KERNEL

• The Microkernel makes use of a small OS that
  provides the very basic service (scheduling ,
  interrupt handling , message passing) rest of the
  kernel (file system, device drivers, networking
  stack) runs as applications.

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EMBEDDED LINUX ARCHITECTUREArchitecture of
Embedded Linux MICRO KERNEL
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OSss Philosophies

• RT-Kernel that provides no memory protection (to
  make system more real time at the cost of
  reliability)
• Microkernel provides memory protection to
  individual kernel subsystem. (at the cost of
  complexity)
• Linux kernel is Monolithic kernel, entire kernel
  operates on a single memory space.