1 CS-550: Materials for the Final Exam - Tue., Dec. 11, 2001, 8 a.m. Distributed Systems 8.Client-server computing Architecture, Relational database applications Classes of client/server applications Three-tier client/server architecture, File cache consistency, Middleware 9.Message passing, clusters, and implementation of clusters in representative OSs Distributed message passing: Send/Receive primitives, reliability vs. unreliability, blocking vs. non-blocking, Remote Procedure Calls (RPCs) Clusters: configurations, OS design issues, architectures Case studies: W2K Cluster Server, Sun Cluster, Beowulf and Linux clusters 10.Distributed resource management: distributed shared memory (DSM) Algorithms for implementing DSM: Central Server, Migration, Read-Replication, and Full-Replication Memory coherence and coherence protocols: Write-invalidate, Write-update Case studies: IVY, Mirage, Clouds 11.Distributed resource management: distributed file systems Services provided: name server, cache manager. Client-server architecture. Mechanisms: mounting, caching, hints, bulk data transfer, encryption Design issues: name and name resolution, caching, writing policy, availability, scalability, and semantics Case studies: Sun Network File System (NFS)

2 CS-550: Materials for the Final Exam (cont.) Distributed Systems (cont.) 12.Distributed process management: process migration Mechanisms: initiation of migration Implementation: Strategies for migration of process address space (eager-all, pre-copy, eager- dirty,copy-on-reference, flushing), strategies for the migration of files and links Negotiation of migration. Eviction. 13.Distributed process management: distributed global states and distributed mutual exclusion Distributed systems limitations: absence of global clock and shared memory Global state: Distributed Snapshot Algorithm Ordering of events: Lamport’s method, Vector Clocks Local and global states based on messages Mutual exclusion algorithms: Non-token-based algorithms (Distributed queue/Lamport’s algorithm, Ricart and Agrawala algorithm), and Token-based algorithms (Suzuki-Kasami broadcast algorithm) 14.Distributed process management: distributed deadlock Deadlock handling strategies in resource allocation: prevention, avoidance, detection Deadlock in message communication: mutual waiting, unavailability of message buffers

3 CS-550: Materials for the Final Exam (cont.) Special topics 15.Protection and security – 1 The Access Matrix Model: possible implementations Capability-based method: principles, addressing, revocation, domain switching 16.Protection and security – 2 The Access Matrix Model: possible implementations (cont.) Access Control List Method: principles, efficiency, authority to change Lock-Key Method: principles, operation The Access Matrix Model: changing the protection state Advance models of protection: Take-Grant Model and Bell-LaPadula Model Case studies: UNIX. Hydra Kernel, Amoeba 17.Recovery Backward error recovery: operation-based approach and state-based approach Recovery in concurrent systems: orphan messages, domino effect, livelock problem Consistent set of checkpoints 18.Fault-tolerance Approaches: mask failures, well-defined behavior Atomic actions, committing, voting protocols, failure resilient processes, fault-tolerant block