CS 550 Comparative Operating Systems ChorusOS Sun Microsystems Operating System -------------------------------------------------------------------------- Java Based OS Hemalkumar Doshi Instructor: Dr. Marius Soneru Course: CS 550 Comparative Operating Systems CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Overview -------------------------------------------------------------------------- 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 CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems History of the ChorusOS -------------------------------------------------------------------------- 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 CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Goals of Chorus -------------------------------------------------------------------------- Enhancement of Unix Dynamically Loadable Servers Real Time Operations Improve network communication Portability CS 550 Comparative Operating Systems CS550 Comparative Operating Systems

CS 550 Comparative Operating Systems ChorusOS Abstraction -------------------------------------------------------------------------- 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. CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems ChorusOS Operating System Kernel -------------------------------------------------------------------------- CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Product Components -------------------------------------------------------------------------- Core Executive Support for Multiple Independent Applications. Support for user and system applications Support for applications in user and supervisor address space Dynamic Memory Management CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Product Components Cont… -------------------------------------------------------------------------- Schedulers Real-time scheduler Priority-based, pre-emptive FIFO Multi-class scheduler Priority-based with fixed-time quantum User defined policy CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Product Components Cont… -------------------------------------------------------------------------- Communications Local IPC: Single-board, asynchronous, synchronous, and multicast communication Distributed IPC: Location-transparent extension to multiple IPC communication sites Real-time message queues Shared memory CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Product Components Cont… -------------------------------------------------------------------------- Memory Management Flat memory: Management of physical memory, no protection Protected memory: Multiple protected address spaces Virtual memory: Page-based protected address spaces, optional on-demand paging CS 550 Comparative Operating Systems

Product Components Cont… Synchronization Semaphores Mutexes Event flags CS 550 Comparative Operating Systems

Product Components Cont… Time Services Timers: One-shot or periodic, usable from both supervisor and user-mode applications Time of day: Universal time Real Time Clock (RTC) CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems ChorusOS Layers -------------------------------------------------------------------------- UNIX Subsystem Object-Oriented subsystem User process U1 U2 U3 User Address Space System process S1 S2 S3 Management of names, processes, threads, memory, and communication K1 K2 Kernel Address Space Micro-kernel CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems How Chorus is Used in a Distributed System -------------------------------------------------------------------------- Three layer communication User interface to system System interface to kernel Kernel interface to micro-kernel Uses message passing between process and threads CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Features and Benefits of ChorusOS -------------------------------------------------------------------------- Memory Protection Hot Restart Dynamic Reconfiguration CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Features and Benefits of ChorusOS Cont… -------------------------------------------------------------------------- Component-based architecture for super-configurability Mission-Critical Quality Exceptional scalability Transparent Distribution Code re-use Multiple OS personalities and APIs CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems ChorusOS Application Overview -------------------------------------------------------------------------- Wireless Networks Private and Public Switches (PBXs) Datacom Systems Internetworking Equipment Transmission Equipment Line Cards Cellular Networks Network Monitoring Equipment Satellite Transmission Systems CS 550 Comparative Operating Systems

CS 550 Comparative Operating Systems Conclusion -------------------------------------------------------------------------- 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 CS 550 Comparative Operating Systems