chapter 3

Question 1

what is an arch style?

Answer 1

is a description of component and connector types and the pattern of their run time

• constrain arch design decisions
• applicable in a dev’t context
• benefit a system

Question 2

______________ is a named collection of arch design decisions?

Answer 2

arch styles

Question 3

what are properties of arch styles?

Answer 3

PAS == V Standard Settings
- vocabulary of design elements
—— filter, server, pipe, object
- set of config rules
—– comp can connect only to 2 other comp
- semantic interpretations
—— design elements have well defined meanings

Question 4

what are common arch styles?

Answer 4

Common I’LL SDP
- implicit invocation
- layered
- language based
- shared state
- data flow
- peer to peer

Question 5

describe a language based AS with an example

Answer 5

• influenced by the language that implements it
• low level and flexible
  example :
• major programs and subroutines
• OO style

Question 6

describe OO style [ comp-conn ]

Answer 6

components - objects
connectors - method invocations
feature - object abstracts local data
Adv / disadv - abstraction

Question 7

describe a layered AS with examples?

Answer 7

• is a hierarchical organization of system
• each layer acts as:
  server : for UL
  client : for LL
• connectors are protocols
  Example:
• OSI, dbs …
• client server arch

Question 8

describe a client-server ( CS ) arch [ comp-conn ]

Answer 8

components - clients and servers
connectors - RPC protocols

Question 9

what are layers of a CS arch?

Answer 9

presentation
application
data management

Question 10

list types of CS arch styles

Answer 10

• 2 tier
  — fat client model & thin client model
• 3 tier

Question 11

which CS arch type places heavy load on server and network? how?

Answer 11

thin client model,
- server executes data management and application processing
- client only handles presentation

Question 12

which 2 tier CS arch types are suitable for legacy and new CS systems respectively?

Answer 12

thin and fat client model

Question 13

what is a 3 tier CS arch?

Answer 13

• each CS layer has its own tier

Question 14

describe a data flow AS with examples?

Answer 14

• computations are determined by the availability of data
• pattern of data flow is explicit
  Examples:
• Batch / sequential
• pipe and filter [ non seq ]

Question 15

describe a pipe and filter [ comp-conn ]

Answer 15

component - filter [ input data stream to output ds]
connector - pipe
- filters are independent [ no shared states ]
- filter has no knowledge of up or down stream
Examples:
- distributes sys
- parallel programs

Question 16

describe a shared state AS with examples?

Answer 16

• describes a shared data store that is accessed and modified by various components
• central data store is explicitly defined
• aka repository style
  Examples:
• Blackboard
• rule-based

Question 17

describe a blackboard [ comp-conn ]

Answer 17

• has 2 type of comp
  —— central ds - blackboard
  —— components on the blackboard
• system is controlled by the blackboard
  Example : compiler

Question 18

describe an implicit invocation AS with examples?

Answer 18

• event announcements instead of method invocation
• listeners will implicitly invoke methods
• component - interface and methods
• connector - 2 types [ imp or exp methods invoked by the listener ]
  Example:
• publish-subscribe

Question 19

what are the comp, connectors, topology and data elements in a publish-subscribe arch?

Answer 19

component - publisher, subscriber, proxy
connector - a network protocol [ client - server ]
data elements - subscriptions, notifications, info
topology - subscriber connects to publisher directly or indirectly through intermediary protocols

Question 20

describe a peer to peer AS with examples?

Answer 20

• state and behavior is distributed among peers
• peer can be client or server
• robust in terms of failure
• scalable in terms of access to resources

Question 21

what are the comp, connectors, topology and data elements in a peer to peer AS?

Answer 21

comp - peers
conn - network protocols
data elements - network messages
topology :
- may be arbitrary or dynamic
- may have redundant connections b/n peers