Chapter 11 Flashcards
6 Design Issues For Distributed Systems
Transparency
Openness
Scalability
Security
Quality of Service
Failure Management
Transparency
The extent to which the user can tell that the system is distributed.
Openness
How much of the system uses standard protocols for interoperability vs. more specialized protocols.
Scalability
How easy or difficult is it for the system to meet increasing demands?
Security
How defendable is the entire system, and the individual systems thereof?
Quality of Service
How is QoS Specified and how should it be implemented to an acceptable level for users?
Failure Management
How can failures be detected, contained, and repaired?
Interaction Types in Distributed Systems
Procedural (synchronous)
Message-Based (asynchronous)
Procedural Interactions
One computer calling on a known service offered by
some other computer and waiting for that service to be delivered.
Message-Based Interaction
Involves the “sending” computer defining information
about what is required in a message, which is then sent to another computer. Messages usually
transmit more information in a single interaction than a procedure call to another machine.
What services does Middleware provide?
Interaction Support
The provision of common services, such as authorization and authentication.
Layers of a Client-Server Architectural Pattern
Presentation
Data Handling
Application Processing
Database
Presentation Layer
Manages how information is presented to the user as well as all user interactions
- What the user sees
Data-Handling Layer
Manages data that passes to and from the client
Application Processing Layer
Implements the logic and required functionality
