ManRiX, The Design of Robust and Efficient Microkernel

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ManRiX, The Design of Robust and Efficient
Microkernel

• Presented by
• Manish Regmi (regmi.manish_at_gmail.com)
• Rajesh Bikram R.C. (rajesh.rc_at_gmail.com)
• NITC (Nepal information Technology center)
• Singhadurbar Kathmandu, Nepal

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Introduction

• Microkernel
• A tiny kernel with very essential services in
  Kernel space and rest services in user space.
• ManRiX
• Microkernel architecture with POSIX compliance.
• Written from scratch using C Assembly.
• Separate architecture dependent and independent
  files.
• Open Source project.

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ManRiXs Design
ManRiXs Microkernel
ManRiXs Architecture

• Microkernel based Design.
• Only few essential services in Kernel space.
• All other services in User Space.
• Applications Communicate through IPC.

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Microkernel Components

• Process and Threads
• Process Passive Entity and Threads Active entity.
• Process just encapsulates the threads and
  provides address
• space.
• Memory Management
• Memory Manager is based in Machs VM design.
• VM manager is divided into two parts, the machine
  dependent part called that Pmap and the machine
  independent part called the vmmap.
• Supports read/write sharing of memory and copy on
  write sharing of memory.
• Uses a slab allocator (conceived by Solaris) to
  allocate kernel memory.

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Contd

• POSIX Signal and Timers.
• Signals provide a mechanism for notifying
  processes of system events.
• 26 signals standard POSIX signals and 5 are
  Real-time Signals.
• Inter Process Communication (IPC).
• IPC through Synchronous Message Passing.
• Three types of messages
• SHORT messages in CPU Registers.
• LONG Copying of messages (lt 256 bytes).
• MAP Through Page Table Mapping.
• Interrupt Management
• Microkernel doesnt handle interrupts in kernel
  space.
• Microkernel acts as an IRQ redirector. User Space
  Applications run the Interrupt Handler.
• Idle Hooking
• ManRiX microkernel is capable of making effective
  use of idle CPU.
• The user can hook a function to run when the
  processors are idle.

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Contd

• Kernel Preemption
• Microkernel is a fully preemptible. It means that
  it is able to preempt a thread even if it is
  running in kernel mode.
• Highly increases the responsiveness of the system
  and decreases the latencies.
• Preemption can be disabled at critical section.
• Symmetric Multiprocessor (SMP) support
• ManRiX supports Multiprocessors.
• For Now supports Intel Multi Processors (MP)
  systems only.
• Kernel Synchronization through Spin locks.
• Scheduler
• Supports POSIX style scheduler.
• 128 priorities where numerically lower value
  means low priority and vice versa.
• Scheduler is capable of distinguishing between
  interactive and non interactive threads.
• Scheduler is aware of multiprocessors. Each
  processor has its own run queue.
• Automatic balancing of Load.

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User Space Components

• Based on Client Server Architecture
• Reduce IPC overhead through implementation
• Important Components are
• File server.
• Console server.
• Separate Device Driver managers for separate
  devices.
• Bus manager to manage PCI, USB Buses.
• ATA manager for managing IDE disks.
• Floppy Manager for Managing Floppy Controllers.
• Miscellaneous manager for those who do not have
  their own server.

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ManRiXgtgt Microkernelgtgt POSIX

• Why ManRiX?
• Learn how Operating Systems, Device Drivers work.
• An attempt to make fast Microkernel based OS.
• Why Microkernel?
• Microkernel design makes ManRiX modular and
  scalable.
• The fault in one subsystem does not bring the
  whole system down.
• Subsystems and drivers can be restarted at
  runtime.
• Microkernel code grows slower than that of
  Monolithic kernels.
• Why POSIX?
• End users and software developers does not need
  to learn ManRiX specific things.
• Cuts down Training Cost and time.
• UNIX/Linux programs will be source compatible
  with ManRiX.

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Future Plans

• High Availability Manager.
• Network Manager.
• Porting open source applications
• Support X windows and different window managers
• Port to different architectures like PPC, X86_64,
  Motorola, ARM etc.
• Make it real time capable.

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QA

• Thank You!

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