Software Engineering Quiz 2 (Lecture 7 ) - Software Quality

reasons for Peer reviews

-improve quality -catches 80% of all errors if done properly -catches both coding errors and design errors -enforce the spirit of any organization standards -training and insurance

Statistical Quality Assurance

-information about software defects is collected and categorized -each defect is traced back to tis cause - using the parteo principle isolated the vital few defect causes -move to correct the problems that caused the defects

Probability of Failure on Demand (POFOD)

0.001, for every 1000 request the service fails per time unit

Rate fo Fault Occurrence (ROCOF)

0.02, two failures for each 100 operational time units of opeartion

by definition it should not but - a program running continuously for a long period of time may work increasingly slower or even crash - performance decreases with number of concurrent users and size of data - maintainability decreases with time -software becomes obsolete very quickly

Does usage and time cause degradation of software product quality?

Monitoring the products

Focus on the quality of product within each phase of the SDLC. Objective: identify and remove defects throughout the lifecycle as early as possible

framework of quality assurance process

Involves checking standard compliance

Realiability

MTBF/(1 + MTBF)

Availability

MTBF/(MTBF + MTTR)

What are the SQA plan parts?

Management section, documentation section, standards, practices and conventions section, review and audits section, test section, problem reporting and corrective action section,

process and products

Monitoring ______ and _____ throughout the software development lifecycle to ensure the quality of the delivered products

-prepare SQA plan for the project -participate in the development of the project's software process description -review software engineering activities to verify compliance with he defined software process - audit designated software work products to verify compliance with those defined as part fo the software process - ensure that any deviations in software or work products are documented and handled according to a documented procedures - record any evidence of noncompliance and reports them to management

One primary resources is SQA Group who:

Software Safety

SQA activity that focuses on identifying potential hazards that may cause a software system to fail. Early identification of software hazards allow developers to specify design features to can eliminate or at least control the impact of potential hazards. Software reliability involves determining the likelihood that a failure will occur without regard to consequences of failures

process applied, resources expended, end product quality attributes

Software engineers strive to control the following...

-incomplete and often inconsistent specifications - tension between customer and developer quality requirements - requirements are hard to specify in an unambiguous way

What are problems with software quality ?

complexity, maintainability, understandably, reusability, documentation

What are the attributes of Code quality?

architectural integrity, component completeness, interface complexity patterns

What are the attributes of Design Quality?

resources allocation, completion rate, review effectiveness, testing effectiveness,

What are the attributes of QC effectiveness?

ambiguity, completeness, understandably, volatility, traceability, model clarity

What are the attributes of Requirements Quality?

Mean time between failure

What does MTBF mean?

Mean time to Repair

What does MTTR mean?

variation control

What is the heart of quality control

Quality assurance

auditing and reporting procedures used to provide management with data needed to make proactive decisions

Mean Time to Failure (MTTF)

average time between observed failure

Encapsulation of best practices

avoids repetition of past mistakes

External failure costs

compliant resolution, product return and replacement, help line support, warranty work

Static Validation Techniques

concerned with analysis of documentation, focus is on finding system errors and identifying potential problems that my arise during system operation, documents may be prepared to support static validation

product standards

define characteristic that all components should exhibit

Process standards

define how the software process should be enacted

Software Reliability

defined as the probability of failure free operation fo a computer program in a specified environment for a specified time period. Can be measured directly and estimated using historical and developmental data. Software reliability problems can usually e traced back to errors in design or implementation

problem reporting and corrective action section

defines procedures for reporting, tracking and resolving errors or defects, identifies organizational responsibilities for these activities

quality (IEEE)

degree to which a system, component, or process meets specified requirements, and customer or user needs tor expectations

Quality of conformance

degree to which design specifications are followed in manufacturing the product

documentation secition

describes each work product produced as part of the software process

management section

describes the place of SQA in the structure of the organization

Kaizen

development a process that is visible, repeatable and measurable

Atarimae hinshitsu

examine the intangibles that affect the process and work to optimize their impact on the process

Kanse

examine the way the product is used by the customer with an eye to improving both the product and development process

Appraisal costs

in-process and inter-process inspection, equipment, calibration and maintenance, testing

Standards developement

involve practitioners in development, review standards and their usage regularly, detailed standards should have associated tool support

total quality management

kaizen, atarimae hinshitsu, kanse , miryokuteki hinshitsu

standards, practices, and conventions section

lists all applicable standards/practices applied during the software process and any metrics to be collected as part of the software engineering work

Miryokuteki hinshitsu

observe product use int eh market place to uncover new product applications and identify new product to develop

review and audits sectoin

provides an overview of the approach used in the reviews and audits to be conducted during project

Monitoring the process

provides management with objective feedback regarding process compliance to approved plans, procedures, standards and analyses

Software reviews

purpose is to find defects before they are passed on to another software engineering activity or released to the customer

Prevention costs

quality planing, formal technical reviews, test equipment, training

test section

references the test plan and procedure document and defines test record keeping requirements

quality of design

refers to characteristics designers specify for the end product to be constructed

Failure costs

rework, repair, failure mode analysis

Quality control

series of inspections, reviews , and tests used to ensure conformance of a work product to its specifications

Software Quality Assurance

set of systematic activities providing evidence of ability of the software process to produce a software product that is fit to use

standards

the key to effective quality management that might be international, national, organizational or project based

quality (ISO)

the totality of features and characteristics of a product or service that bear on its ability to satisfy specified or implied needs

Software Process Quality Assessment

use of standards and process models has a positive impact on the quality fo the software product