Zusammenfassung der Ressource
Distributed systems definition
- Definiton
- collection of independent computers
- appear users as a single coherent systems
- one in which components
- are located in a networked computers
- communicate, coordinate actions
- passing messages
- Characteristics
- concurrency
- no global clock
- independent failures
- why are chosen?
- scale
- processing
- data
- big data
- continues to grow
- applications
- data intensive
- diversity in application domains
- collaboration
- vs individual computers with limited resources
- memory and cache
- hard disk drive
- capacity
- channels
- limited bandwidth
- processor capacity grows faster
than memory capacity (55% vs 7%)
- processors
- CMP (chip multiprocessors)
- Moore's pace
- even if many cores are placed in a CMP, the challenge is
to deliver input data to these cores for processing
- cost
- requeriments
- programming models and concurrency
- problems as parallel process
- execute each process in different machines
- communication
- process in differents machines
- exchange information
- sincronization
- process
- cooperate
- synchronize
- consistency
and replication
- enhance reability
- improve performance
- fault tolerance
- recover for partial failures
- security
- process gets access rights
to whom is entitled to
- virtualization
- extend interfaces to
another system
- reduce diversity or platforms
- high degree of
- portability
- flexibility
- challenges
- heterogeneity, openness, security,
scalability, failure handling. concurrency of
components, transparency, providing QoS