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Home > Computer Science > Computer Fundamentals
 
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Computer Fundamentals
 

The process followed in making a determination is called Feasibility Study. This type of study clearly specifies that, the project should be taken up or not.

Different types of fusibilities are

1. Technical is the most difficult to determine.
2. Economical
3. Operational
4. Time
5. Legal
6. Social
7. Management

Feasibility Study has to follow 8 steps, they are

1. Form a project team & appoint a PL
2. Prepare system flowcharts
3. Enumerate potential proposed systems
4. Define & identify characteristics of proposed system
5. Determine & evaluate performance & cost effectiveness of each proposed system
6. Weight system performance & cost data
7. Select the best proposed system
8. Prepare & report final project directive to management.

System analysis is the fact finding followed by analysis of the facts. Data analysis is also considered a pre-requisite condition for cost/benefit analysis.

While considering the design alternatives, one should keep following points in mind to choose a better alternative.

1. Greater speed of processing
2. Effective procedure to eliminate errors
3. Better accuracy
4. Faster retrieval of data
5. Integration of data
6. Larger capacity of storing data with reduced cost
7. Data Security.

Cost benefit analysis will give a picture of how much cost will be incurred by the project. There are four benefits of projects about cost,

1. Cost Saving: This lead to reductions in administrative & operational costs.
2. Cost avoidance: These are those which eliminate future in administrative & operational costs
3. Improved Service: Are those where performance of the system is improved by a new computer based software system
4. Improved Information: Is where computer based methods lead to better information for decision making.

Cost benefits are classified as

1. Tangible or intangible
2. Fixed or variable
3. Direct or indirect.

Cost benefit can be summarize as

1. Method by which we estimate the value of the gross benefits of a new system specification.
2. Method by which we find & determine the increased operating costs associated with the above mentioned gross benefits.
3. The subtraction of these operating costs from the associated gross benefits to arrive at net benefits.
4. Method by which we find & estimate the monetary value of the development costs that produce the above mentioned benefits.
5. Methods by which we show the time phased relationship between different costs.

Learning as much as from the existing system is called Fact-finding Different methods of Fact findings are

1. Interviews Personnel
2. Questionnaires, can have multi choice, rating, open ended & Ranking questions.
3. Observing current system
4. Going thru the current forms & documents
5. Find the data flow in the existing system
6. Define the system requirements

After finding the data, analyst prepares a Data Flow Diagram (DFD) which depicts the flow of data in different elements of the system. Which gives us a graphical Overview representation. To draw a analysis DFD,

1. Look at the system from the inside to the outside
2. Identify the activities
3. Locate the data flows
4. Show the relationship between activities
5. Find the internal i/p or o/p that exist within the system
6. Level complex process in the DFD into simpler ones
7. Look for duplication of data flows or data stores.

Data Dictionaries defines each term (called a data element) encountered during the analysis & design of the new system. Data elements can describe files, data flows or processes. It helps analyst to define precisely what they mean by a particular file, data flow or process. Data dictionary uses few major symbols, they are

= Equivalent to

+ AND

[ ] either/or

( ) optional entry.

There are four rules to be followed while constructing a Data Dictionary.

1. Words should be defined to stand for what they mean & not the variable names by which they may be described in the program.
2. Each word must be Unique.
3. Aliases or synonyms are allowed when two or more elements show the same meaning.
4. Self-defining words should not be decomposed.

After following the these rules, define variables with there data types and their properties like unique or increments automatically. There are two types of Data Dictionaries

1. Integrated: is a related to one DBMS
2. Stand Alone: is not tied to any DBMS, although it may have advantages of DBMS.

Both types of DD can be identified by functions as Passive, Active or in-line.

The functionally passive DD performs only Documentation.

The Active DD supports program and operations development by exporting database definitions for languages like COBOL & JCL for execution time performance.

An in-line DD is active during program execution, performing such feats as transaction validation & editing

 
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