Transcript ChorusOS Sun Microsystems Operating System

ChorusOS
Sun Microsystems Operating System
-------------------------------------------------------------------------Java Based OS
Hemalkumar Doshi
Instructor: Dr. Marius Soneru
Course: CS 550 Comparative Operating Systems
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Overview
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History of the ChorusOS
Goals of ChorusOS
ChorusOS Abstraction
ChorusOS Operating System Kernel
Product Components
ChorusOS Layers
How Chorus is Used in a Distributed System
Features and Benefits of ChorusOS
Chorus Application Overview
Conclusion
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History of the ChorusOS
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• Originally developed as French research
project
• Bought by Sun Microsystems in 1997
• V0 – collection of actors
• V1 – French SM90 Multiprocessor
[Ethernet]
• V2 – Move to Micro-kernel
• V3 – Sun bought; RPC implemented
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Goals of Chorus
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Enhancement of Unix
Dynamically Loadable Servers
Real Time Operations
Improve network communication
Portability
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ChorusOS Abstraction
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Actor: is an execution environment.It can have one or more thread
Ports: is an unidirectional communication channel with an associated message queue.
Ports can be migrated between actors.
Port groups: Ports can be made members of port groups. A port group is a destination for
messages, and there are several addressing modes for sending messages to a port group.
Messages: A Chorus message consists of a variable length body (limited to 64 kilobytes),
and optionally a fixed-size (64-byte) header.
Regions, segments and local caches: An actor’s address space is divided into regions. A
region can be mapped onto a portion of a Segment. For each mapped segment the kernel
keeps a local cache.
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ChorusOS Operating System
Kernel
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Product Components
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Core Executive
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Support for Multiple Independent Applications.
Support for user and system applications
Support for applications in user and supervisor address space
Dynamic Memory Management
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Product Components Cont…
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Schedulers
o Real-time scheduler
 Priority-based, pre-emptive FIFO
o Multi-class scheduler
 Priority-based, pre-emptive FIFO
 Priority-based with fixed-time quantum
o User defined policy
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Product Components Cont…
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Communications
o Local IPC: Single-board, asynchronous,
synchronous, and multicast communication
o Distributed IPC: Location-transparent extension to
multiple IPC communication sites
o Real-time message queues
o Shared memory
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Product Components Cont…
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Memory Management
o Flat memory: Management of physical memory, no
protection
o Protected memory: Multiple protected address
spaces
o Virtual memory: Page-based protected address
spaces, optional on-demand paging
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Product Components Cont…
Synchronization
o Semaphores
o Mutexes
o Event flags
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Product Components Cont…
Time Services
o Timers: One-shot or periodic, usable from both supervisor
and user-mode applications
o Time of day: Universal time
o Real Time Clock (RTC)
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ChorusOS Layers
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Object-Oriented
Subsystem
subsystem
U1
User
Address
Space
S1
U2
S2
K1
Kernel
Address
Space
U3
S3
K2
User
process
System
process
Management of
names, processes,
threads, memory,
and communication
Micro-kernel
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How Chorus is Used in a
Distributed System
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• Three layer communication
 User interface to system
 System interface to kernel
 Kernel interface to micro-kernel
• Uses message passing between process and
threads
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Features and Benefits of
ChorusOS
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• Memory Protection
• Hot Restart
• Dynamic Reconfiguration
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Features and Benefits of
ChorusOS Cont…
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• Component-based architecture for superconfigurability
• Mission-Critical Quality
• Exceptional scalability
• Transparent Distribution
• Code re-use
• Multiple OS personalities and APIs
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ChorusOS Application Overview
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Wireless Networks
Private and Public Switches (PBXs)
Datacom Systems
Internetworking Equipment
Transmission Equipment
Line Cards
Cellular Networks
Network Monitoring Equipment
Satellite Transmission Systems
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Conclusion
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• Micro-kernel based system used in
distributed operating systems
• Provides binary compatibility with UNIX
• Consist of three layers
 Kernel – contains micro-kernel
 Subsystems – support for user programs
 User processes at top layer
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