22-12-2012, 12:27 PM
Distributed computing environment
Distributed computing.ppt (Size: 941 KB / Downloads: 38)
Introduction
Defn: OSF’s Distributed Computing Environment provides services and tools for supporting creation and maintenance of distributed applications in a heterogeneous environment
It is a layer between operating system, network services and the distributed applications
Why DCE ?
DCE provides tools (DCE Threads, DCE RPC) and services (Directory Service etc.,) to support distributed applications
DCE services are integrated and comprehensive
Provides inter-operability and portability across heterogeneous platforms
Supports data sharing
DCE inter-operates with global computing environments
DCE ComponentsTwo Categories
Distributed Programming Facilities
DCE Threads
DCE Remote Procedure Call (RPC)
Distributed Services
DCE Directory Service
DCE Distributed Time Service
DCE Security Service
DCE Distributed File System
DCE Technology Components
DCE Programming Facilities
DCE Threads
DCE Remote Procedure Call
DCE Distributed Services
DCE Directory Service
DCE Distributed Time Service
DCE Security Service
DCE Distributed File Service
DCE Threads
Importance of multi threading in DCE
Threads are either provided by the operating system kernel or the user space library
DCE threads are provided as user level threads library based on pthreads interface specified by POSIX
It provides the application programmer with an API to create and manipulate threads.
DCE RPC
Facility for calling a procedure on a remote machine like a local procedure
Shields the programmer from details of actual network communication
Components of DCE RPC
Interface Definition Language (IDL)
RPC Runtime (TCP/IP and UDP/IP)
Name Service Independent (NSI) API
Authenticated RPC
Distributed Time Service
Problem with clocks in distributed environment
DCE/DTS provides synchronized time for users in distributed computing environment
Supports event sequencing, duration and scheduling
Synchronized with UTC, an international time standard