A coded set of tables describing this information & stored in a computer system on direct access devices is called a SCHEMA. Which will describe the data aggregate data types & records. All references to data within the program will be for this description, which is known as SUBSCHEMA.

The different types DB organizations are

1. Hierarchical Model
2. Network Model
3. Relational Model

In relational model, rows are known as tuples & columns are known as Attributes. A code is an ordered collection of symbols designed to provide unique identification of an entity or attribute. The main purpose of codes is to facilitate the identification & retrieval of items of information from system. Different types of coding system are

1. Classification code
2. Function code
3. Card code
4. Sequence code
5. Significant digit subset code
6. Mnemonic code
7. Acronym

System Development & Implementation

Two important phases of development are:

1. External development: This deals with the implementation, planning, preparation of manuals, in house training & equipment acquisition & installing.
2. Internal Development: Software development & performance testing are part of Internal development.

Major activities at System Development phase are

1. Implementation & Planning
Plan to test computer program component as individual & integrated.
Personnel training
Conversion plans to convert to manual to automated.

2. Software development phase, preparing flow chart & pseudocode
3. User review
4. Equipment acquisition
5. Coding, debugging & unit testing
6. System testing
7. Manual preparation
8. Personnel training
9. UAT

Prototype is having two major advantages as

1) Its clarifies the all assumptions & issues with user requirements
2) It verifies the feasibility of system design.

The major criteria for hardware/software selection are

1. Define the capabilities that make sense to business
2. Specify the magnitude of the problem
3. Asses the competence of in-house staff
4. H/w & s/w should be considered as package
5. Specify a time frame for selection process
6. Provide user indoctrination.

Selection process will consists of several steps.

1. Requirement analysis
2. System specifications
3. Request for proposal
4. Evaluation & validation
5. Vendor selection

Software selection depends on two streams like Customized & readymade, The main criteria for selecting software are

Benchmarking is a evaluation technique where the software purchaser compare the software with other to find the best of Speed & cost for his business. To select a language, main criteria are

1. Volume of data
2. Complexity of processing
3. Compatibility with other systems
4. Types of i/p & o/p
5. Development efforts

Quality factor for SDLC

Quality Assurance for Software using

1) Testing
2) Verification & Validation
3) Certification

Three Reliability approaches are

1) Error avoidance
2) Error detection & correction
3) Error tolerance

Levels of testing are

1. Unit testing
2. System testing
Program testing
String testing
System testing
System documentation

3. UAT
4. Some other special types of testing are

System control is used to achieve

Types of system control are

1. External control: like laws, regulations procedures & policies outside the scope of the system which affect the operations of the system
2. Internal controls are basically plans, procedures, Guideline, rules & checks under which a system must function.

Good documentation means

1. Availability
2. Objectivity
3. Cross referable
4. Easy to maintain
5. Completeness

Types of documentation are

1. Program documentation
2. Operation
3. User
4. Management
5. Systems

Software design & documentation Tools are

1. Structured flow chart which will contain flow charts for
Process
Decision
Iteration

2. HIPO diagram
3. Warnier/Orr diagrams

Training should be given to two different categories of people,

1. System operator, persons who take care of systems
2. System user, persons who uses the system to enter data.

Training methods that can be used are

1. Vendor & In service
2. In house

There are 4 main conversion method to replace a old system to new system,

1. parallel system
2. Direct
3. Pilot
4. Phase in

Main conversions plans to be

1. Site preparation
2. File & data conversion

Maintenance, different types are

1. Corrective : Repairing, processing or performance failures or making alterations bcoz of previous ill-defined problems
2. Adoption: changing the program function. Enhancing the performance or modify the programs.

Ecological & Green P C, two types of Green PC which doesn’t use chloro fluoro materials,

1. Light Green, consumes 25-30W, its spins IDE & shuts down display
2. Dark green, consumes 15-20W in standby mode, its spins IDE & shuts down display

Disaster recovery is of 4 types

1. Critical
2. Vital
3. Sensitive
4. Non-critical

To fight against the Disaster, we do have 5 different ways to overcome

1. Hot sites
2. Private hot-sites
3. Warm or cold sites
4. Service bureaus
5. Reciprocal agreements

Forms of Software piracy

1. Hard disk loading
2. Soft lifting
3. Software counterfeiting
4. Bulletin board piracy
5. Software rental

Computer crimes are classified as

1. Data related
2. Software related
3. Physical

Ergonomics essentially is the study of the relationship between the human being and the environmental factors affecting the physiological, psychological or anatomical state. The aims of Ergonomics are

1. To improve the efficiency of the interaction between the human & machine through enhancing the effectiveness & efficiency of human activities at work or at home.
2. To maintain the individuality of the worker by considerations of human welfare & human well being in the design procedure, namely in areas of health, safety, satisfaction & comfort of the worker.

Multimedia means a combination of Sound, text & graphics. Multimedia development work follows a path like planning/Design >>>> Production >>>> Distribution. Presentation of graphics in multimedia is achieved thru many ways

1. Bitmaps
2. Vector images, object oriented format using lines & curves, ex CAD.
3. Animation
4. Morphing & warping
5. Digital Audio & video