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software architecture slide 2

chan cti access term levels eas rar trade extern

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33 what are cohension levels from bad to good?

  coincidental

  logical

  temporal

  procedural

  communicational

  sequential

  functional

32 what are coupling levels from bad to good?  

  content

  common

  external

  control

  stamp

  data

  message

  no coupling

31 what is cohesion and coupling

  cohesion:  measure of how strongly a module‘s responsibilities are related, its ‘unity of purpose‘

  coupling:  measure of responsibility overlap beween modules, the probability that modifying one module requires modifying the other.

30 what are catogories of tactics for modifiability?

  reduce size of a module

  increase cohesion

  reduce coupling  

  defer binding

29 what questions should an architect has to consider to plan for modifiability?

  what can change

  what is the likelihood of the change

  when is the change made and who makes it

  what is the cost of change

28 what is modifiablility

  modifiability is about change and our interest in

  it is the coust and risk of making changes

27 what are catogries of tactics for security?

  Detect ATtacks

  Resist attacks

  React to attacks

  recover from attacks

26 what are other characteristics that support CIA?

  Authentication

  Nonrepudiation

  Authorization

  

25 what are CIA characteristics of security

  Confidentiality

  Integrity

  Availability

24 what is attack

  attack is action against system with the intention of doing harm

    unauthorized attempt to access servides

    attempt to deny services to legitimate users

23 what is security?

  security is a measure of the system‘s ability to protect data and information form unauthorized access while still providing access to people and systems taht are authorized

23 what catogories for performance tactics?

  control resource demand

  Manage resource

22 what is performance?

  Performance is about time and the software system‘s ability to meet timing requirements.

21 what is orchestrate?

  Use a control mechanism to coordinate, manage and sequence the invocation of services

20 what are the proxy design pattern?

19 what catogories for interoperability tactics?

  Locate

    service discovery

  manage interface

    tailor interface

18 what is interoperability

  Interoperability is about the degree to which two ore more systems can usefully exchage meaningful information via interfaces in a particular context.

17 what are catagories of availability tactics?

  Detect Faults

  Recover from Faults

    preparation and repair

    reintroduction

  Prevent Faults

16 what do availability tactics do?

  Availability tactics enable a system to endure faults so that services remain compliant with their specifications

  The tactics keep faults from becoming failures or at least bound the effects of the fault and make repair possible.

15 what is fault or combination of faults

  A fault has the potantial to cause a failure.

    A failure occurs when the system no longer delivers a service conssitent with its specification

    such a failure is observable by the system‘s actors

14 what is availability?

  Availability refers to the ability of a system to mask or repair faults such that the cumulative service outage period does not exceed a required value over a specific time interval.

13 what are the categories of design decisions to make?

  Allocation of responsibilities

  Coordination model

  Data model

  Management of resources

  Mapping among architectural elements

  Choice of techonology

  Binding time decisions

12 what is the difference between tactics and architectural/design patterns?

  A tactic provedes a solution for one quality attribute

  A pattern provides a bundled solution for multiple attributes

11 what are tactics

  tactics are design decision influencing the achievement of a quality attribute responce

  tactics, like architectural/design patterns, are techniques that architects have been using for years.

  Not invented, but captured from parctice.

  

10 how to achieve quality attribute

  architects can use architectural tactics to achieve the required quality attributes

9 how to specify quality attribute requirement?

  using six-part quality attribute scenario‘s

    source of stimulus

    stimulus

    environment

    artifact

    resonse

    response measure

8 what is the solution of conflicts between quality attributes

  trade-off of architectural decisions.

7 are there conflicts between quality attributes.

  Yes

    withicn complex systems, quality attributes can never be achieved in isolation. The achievement of any one will have an effect, sometimes positive and somtimes negative, on the achievement of others.

6how many cantegories for quality arrtributes

  there are two categories of quality attributes

    those that describe some property of the system at runtime

      such as availability, performance or usability

    those that describe some property of the development of the system

      such as modifiability or testability

5 what is architect‘s interest in functionality?

  the architect‘s interest in functionality isin how it interacts with and constrains the system‘s qualities.

4 why responsibilites can not be allocated arbitrarily to any modules?

  Although responsibilites can be allocated arbitrarily to any modules, soft ware architecture constrains this allocation when quality attributes are important.

3 where does the most basic of architectural structures come from?

  functionality is achieved by assigning responsibilities to architectural elemetns, resulting in one of the most basic of architectural structures.

2 what is the relationship between functionality and architecture?

  Functionality does not determinde architecture

    Given a set of required functionalities, there is no end to the architectures you could create to satisfy that functionality.

    if functionality were theonly thing that mattered, you wouldn‘t have to divide the system into pieces at all.

1 what is functionality?

  functionality is the ability of the system to do the work for which it was intended.

  

software architecture slide 2