tailieunhanh - Lecture Operating system concepts (Fifth edition): Module 16 - Avi Silberschatz, Peter Galvin

Module 16 - Distributed system structures. Chapter 16 examines distributed-system structures, including coverage of remote services, thread-management, and the Open Software Foundation’s Distributed Computing Environment (DCE) thread package. | Lecture Operating system concepts Fifth edition Module 16 - Avi Silberschatz Peter Galvin Module 16 Distributed-System Structures Network-Operating Systems Distributed-Operating Systems Remote Services Robustness Design Issues Silberschatz and Galvin 1998 Network-Operating Systems Users are aware of multiplicity of machines. Access to resources of various machines is done explicitly by Remote logging into the appropriate remote machine. Transferring data from remote machines to local machines via the File Transfer Protocol FTP mechanism. Silberschatz and Galvin 1998 Distributed-Operating Systems Users not aware of multiplicity of machines. Access to remote resources similar to access to local resources. Data Migration transfer data by transferring entire file or transferring only those portions of the file necessary for the immediate task. Computation Migration transfer the computation rather than the data across the system. Silberschatz and Galvin 1998 Distributed-Operating Systems Cont. Process Migration execute an entire process or parts of it at different sites. Load balancing distribute processes across netowrk to even the workload. Computation speedup subprocesses can run concurrently on different sites. Hardware preference process execution may require specialized processor. Software preference required software may be available at only a particular site. Data access run process remotely rather than transfer all data locally. Silberschatz and Galvin 1998 Remote Services Requests for access to a remote file are delivered to the server. Access requests are translated to messages for the server and the server replies are packed as messages and sent back to the user. A common way to achieve this is via the Remote Procedure Call RPC paradigm. Messages addressed t an RPC daemon listening to a port on the remote system contain the name of a process to run and the parameters to pass to the process. The process is executed as requested and any .