Top 29 System Analysis And Design Interview Questions You Must Prepare 19.Mar.2024

System design is the process of defining the architecture, components, modules, interfaces, and data for a system to satisfy specified requirements. Systems design could be seen as the application of systems theory to product development.

Types of DFD : DFDs are of two types: Physical DFD and Logical DFD. 

Physical DFD :

  • It is implementation dependent. It shows which functions are performed.
  • It provides low level details of hardware, software, files, and people.
  • It depicts how the current system operates and how a system will be implemented.

Logical DFD :

  • It is implementation independent. It focuses only on the flow of data between processes.
  • It explains events of systems and data required by each event.
  • It shows how business operates; not how the system can be implemented.

A system has the following properties −

  • Organization : Organization implies structure and order. It is the arrangement of components that helps to achieve predetermined objectives.
  • Interaction : It is defined by the manner in which the components operate with each other.

For example, in an organization, purchasing department must interact with production department and payroll with personnel department.

  • Interdependence : Interdependence means how the components of a system depend on one another. For proper functioning, the components are coordinated and linked together according to a specified plan. The output of one subsystem is the required by other subsystem as input.
  • Integration : Integration is concerned with how a system components are connected together. It means that the parts of the system work together within the system even if each part performs a unique function.

System Documentation : System documentation serves as the technical specifications for the IS and how the objectives of the IS are accomplished. Users, managers and IS owners need never reference system documentation. System documentation provides the basis for understanding the technical aspects of the IS when modifications are made.

  • It describes each program within the IS and the entire IS itself.
  • It describes the system’s functions, the way they are implemented, each program's purpose within the entire IS with respect to the order of execution, information passed to and from programs, and overall system flow.
  • It includes data dictionary entries, data flow diagrams, object models, screen layouts, source documents, and the systems request that initiated the project.
  • Most of the system documentation is prepared during the system analysis and system design phases.
  • During systems implementation, an analyst must review system documentation to verify that it is complete, accurate, and up-to-date, and including any changes made during the implementation process.

Major Activities in requirement Determination :

Requirements Anticipation : 

  • It predicts the characteristics of system based on previous experience which include certain problems or features and requirements for a new system.
  • It can lead to analysis of areas that would otherwise go unnoticed by inexperienced analyst. But if shortcuts are taken and bias is introduced in conducting the investigation, then requirement Anticipation can be half-baked.

Requirements Investigation : 

  • It is studying the current system and documenting its features for further analysis.
  • It is at the heart of system analysis where analyst documenting and describing system features using fact-finding techniques, prototyping, and computer assisted tools.

Requirements Specifications :

  • It includes the analysis of data which determine the requirement specification, description of features for new system, and specifying what information requirements will be provided.
  • It includes analysis of factual data, identification of essential requirements, and selection of Requirement-fulfillment strategies.

Types of Files used in an Organization System

Master file − It contains the current information for a system. For example, customer file, student file, telephone directory.

Table file − It is a type of master file that changes infrequently and stored in a tabular format. For example, storing Zipcode.

Transaction file − It contains the day-to-day information generated from business activities. It is used to update or process the master file. For example, Addresses of the employees.

Temporary file − It is created and used whenever needed by a system.

Mirror file − They are the exact duplicates of other files. Help minimize the risk of downtime in cases when the original becomes unusable. They must be modified each time the original file is changed.

Log files − They contain copies of master and transaction records in order to chronicle any changes that are made to the master file. It facilitates auditing and provides mechanism for recovery in case of system failure.

Archive files − Backup files that contain historical versions of other files.

Feasibility Study : Feasibility Study can be considered as preliminary investigation that helps the management to take decision about whether study of system should be feasible for development or not.

  • It identifies the possibility of improving an existing system, developing a new system, and produce refined estimates for further development of system.
  • It is used to obtain the outline of the problem and decide whether feasible or appropriate solution exists or not.
  • The main objective of a feasibility study is to acquire problem scope instead of solving the problem.
  • The output of a feasibility study is a formal system proposal act as decision document which includes the complete nature and scope of the proposed system.

Steps Involved in Feasibility Analysis :

The following steps are to be followed while performing feasibility analysis 

  • Form a project team and appoint a project leader.
  • Develop system flowcharts.
  • Identify the deficiencies of current system and set goals.
  • Enumerate the alternative solution or potential candidate system to meet goals.
  • Determine the feasibility of each alternative such as technical feasibility, operational feasibility, etc.
  • Weight the performance and cost effectiveness of each candidate system.
  • Rank the other alternatives and select the best candidate system.
  • Prepare a system proposal of final project directive to management for approval.

Program Documentation : 

  • It describes inputs, outputs, and processing logic for all the program modules.
  • The program documentation process starts in the system analysis phase and continues during implementation.
  • This documentation guides programmers, who construct modules that are well supported by internal and external comments and descriptions that can be understood and maintained easily.

Operations Documentation : Operations documentation contains all the information needed for processing and distributing online and printed output. Operations documentation should be clear, concise, and available online if possible.

It includes the following information

  • Program, systems analyst, programmer, and system identification.
  • Scheduling information for printed output, such as report, execution frequency, and deadlines.
  • Input files, their source, output files, and their destinations.
  • E-mail and report distribution lists.
  • Special forms required, including online forms.
  • Error and informational messages to operators and restart procedures.
  • Special instructions, such as security requirements.

Secondary Research or Background Reading : This method is widely used for information gathering by accessing the gleaned information. It includes any previously gathered information used by the marketer from any internal or external source.

Advantages :

  • It is more openly accessed with the availability of internet.
  • It provides valuable information with low cost and time.
  • It act as forerunner to primary research and aligns the focus of primary research.
  • It is used by the researcher to conclude if the research is worth it as it is available with procedures used and issues in collecting them.

Questionnaires : This method is used by analyst to gather information about various issues of system from large number of persons.

There are two types of questionnaires :

Open-ended Questionnaires − It consists of questions that can be easily and correctly interpreted. They can explore a problem and lead to a specific direction of answer.

Closed-ended Questionnaires − It consists of questions that are used when the systems analyst effectively lists all possible responses, which are mutually exclusive.

Advantages of questionnaires :

  • It is very effective in surveying interests, attitudes, feelings, and beliefs of users which are not co-located.
  • It is useful in situation to know what proportion of a given group approves or disapproves of a particular feature of the proposed system.
  • It is useful to determine the overall opinion before giving any specific direction to the system project.
  • It is more reliable and provides high confidentiality of honest responses.
  • It is appropriate for electing factual information and for statistical data collection which can be emailed and sent by post.

Systems Models :

Schematic Models : 

    • A schematic model is a 2-D chart that shows system elements and their linkages.
    • Different arrows are used to show information flow, material flow, and information feedback.

Flow System Models :

    • A flow system model shows the orderly flow of the material, energy, and information that hold the system together.
    • Program Evaluation and Review Technique (PERT), for example, is used to abstract a real world system in model form.

Static System Models : 

    • They represent one pair of relationships such as activity–time or cost–quantity.
    • The Gantt chart, for example, gives a static picture of an activity-time relationship.

Dynamic System Models :  Business organizations are dynamic systems. A dynamic model approximates the type of organization or application that analysts deal with. It shows an ongoing, constantly changing status of the system. It consists of −

    • Inputs that enter the system
    • The processor through which transformation takes place
    • The program(s) required for processing
    • The output(s) that result from processing.

Types of Systems :

Physical or Abstract Systems : Physical systems are tangible entities. We can touch and feel them.

Physical System may be static or dynamic in nature. For example, desks and chairs are the physical parts of computer center which are static. A programmed computer is a dynamic system in which programs, data, and applications can change according to the user's needs.

Abstract systems are non-physical entities or conceptual that may be formulas, representation or model of a real system.

Open or Closed Systems : An open system must interact with its environment. It receives inputs from and delivers outputs to the outside of the system. For example, an information system which must adapt to the changing environmental conditions.

A closed system does not interact with its environment. It is isolated from environmental influences. A completely closed system is rare in reality.

Adaptive and Non Adaptive System : Adaptive System responds to the change in the environment in a way to improve their performance and to survive. For example, human beings, animals.

Non Adaptive System is the system which does not respond to the environment. For example, machines.

Permanent or Temporary System : Permanent System persists for long time. For example, business policies.

Temporary System is made for specified time and after that they are demolished. For example, A DJ system is set up for a program and it is dissembled after the program.

Natural and Manufactured System : Natural systems are created by the nature. For example, Solar system, seasonal system.

Manufactured System is the man-made system. For example, Rockets, dams, trains.

Deterministic or Probabilistic System  : Deterministic system operates in a predictable manner and the interaction between system components is known with certainty. For example, two molecules of hydrogen and one molecule of oxygen makes water.

Probabilistic System shows uncertain behavior. The exact output is not known. For example, Weather forecasting, mail delivery.

Social, Human-Machine, Machine System : Social System is made up of people. For example, social clubs, societies.

In Human-Machine System, both human and machines are involved to perform a particular task. For example, Computer programming.

Machine System is where human interference is neglected. All the tasks are performed by the machine. For example, an autonomous robot.

Man–Made Information Systems : It is an interconnected set of information resources to manage data for particular organization, under Direct Management Control (DMC).

This system includes hardware, software, communication, data, and application for producing information according to the need of an organization.

Man-made information systems are divided into three types −

  • Formal Information System − It is based on the flow of information in the form of memos, instructions, etc., from top level to lower levels of management.
  • Informal Information System − This is employee based system which solves the day to day work related problems.
  • Computer Based System − This system is directly dependent on the computer for managing business applications. For example, automatic library system, railway reservation system, banking system, etc.

  • It is a technique developed by Larry Constantine to express the requirements of system in a graphical form.
  • It shows the flow of data between various functions of system and specifies how the current system is implemented.
  • It is an initial stage of design phase that functionally divides the requirement specifications down to the lowest level of detail.
  • Its graphical nature makes it a good communication tool between user and analyst or analyst and system designer.
  • It gives an overview of what data a system processes, what transformations are performed, what data are stored, what results are produced and where they flow.

Interviewing : Systems analyst collects information from individuals or groups by interviewing. The analyst can be formal, legalistic, play politics, or be informal; as the success of an interview depends on the skill of analyst as interviewer.

It can be done in two ways 

  • Unstructured Interview : The system analyst conducts question-answer session to acquire basic information of the system.
  • Structured Interview :It has standard questions which user need to respond in either close (objective) or open (descriptive) format.

Advantages of Interviewing :

  • This method is frequently the best source of gathering qualitative information.
  • It is useful for them, who do not communicate effectively in writing or who may not have the time to complete questionnaire.
  • Information can easily be validated and cross checked immediately.
  • It can handle the complex subjects.
  • It is easy to discover key problem by seeking opinions.
  • It bridges the gaps in the areas of misunderstandings and minimizes future problems.

A system must have three basic constraints −

  1. A system must have some structure and behavior which is designed to achieve a predefined objective.
  2. Interconnectivity and interdependence must exist among the system components.
  3. The objectives of the organization have a higher priority than the objectives of its subsystems.

For example, traffic management system, payroll system, automatic library system, human resources information system.

 

User Documentation : It includes instructions and information to the users who will interact with the system. For example, user manuals, help guides, and tutorials. User documentation is valuable in training users and for reference purpose. It must be clear, understandable, and readily accessible to users at all levels.

The users, system owners, analysts, and programmers, all put combined efforts to develop a user’s guide.

A user documentation should include:

  • A system overview that clearly describes all major system features, capabilities, and limitations.
  • Description of source document content, preparation, processing, and, samples.
  • Overview of menu and data entry screen options, contents, and processing instructions.
  • Examples of reports that are produced regularly or available at the user’s request, including samples.
  • Security and audit trail information.
  • Explanation of responsibility for specific input, output, or processing requirements.
  • Procedures for requesting changes and reporting problems.
  • Examples of exceptions and error situations.
  • Frequently asked questions (FAQs).
  • Explanation of how to get help and procedures for updating the user manual.

System design takes the following inputs :

  • Statement of work.
  • Requirement determination plan.
  • Current situation analysis.
  • Proposed system requirements including a conceptual data model, modified DFDs, and Metadata (data about data).
  • Outputs for System Design.

System design gives the following outputs :

  • Infrastructure and organizational changes for the proposed system.
  • A data schema, often a relational schema.
  • Metadata to define the tables/files and columns/data-items.
  • A function hierarchy diagram or web page map that graphically describes the program structure.
  • Actual or pseudocode for each module in the program.
  • A prototype for the proposed system.

It is a process of collecting and interpreting facts, identifying the problems, and decomposition of a system into its components.

System analysis is conducted for the purpose of studying a system or its parts in order to identify its objectives. It is a problem solving technique that improves the system and ensures that all the components of the system work efficiently to accomplish their purpose.

The objective of system must be central. It may be real or stated. It is not uncommon for an organization to state an objective and operate to achieve another.

The users must know the main objective of a computer application early in the analysis for a successful design and conversion.

Structured Analysis is a development method that allows the analyst to understand the system and its activities in a logical way.

It is a systematic approach, which uses graphical tools that analyze and refine the objectives of an existing system and develop a new system specification which can be easily understandable by user.

It has following attributes :

  • It is graphic which specifies the presentation of application.
  • It divides the processes so that it gives a clear picture of system flow.
  • It is logical rather than physical i.e., the elements of system do not depend on vendor or hardware.
  • It is an approach that works from high-level overviews to lower-level details.

Documentation Control :

Documentation is a process of recording the information for any reference or operational purpose. It helps users, managers, and IT staff, who require it. It is important that prepared document must be updated on regular basis to trace the progress of the system easily.

After the implementation of system if the system is working improperly, then documentation helps the administrator to understand the flow of data in the system to correct the flaws and get the system working.

Programmers or systems analysts usually create program and system documentation. Systems analysts usually are responsible for preparing documentation to help users learn the system. In large companies, a technical support team that includes technical writers might assist in the preparation of user documentation and training materials.

Advantages :

  • It can reduce system downtime, cut costs, and speed up maintenance tasks.
  • It provides the clear description of formal flow of present system and helps to understand the type of input data and how the output can be produced.
  • It provides effective and efficient way of communication between technical and nontechnical users about system.
  • It facilitates the training of new user so that he can easily understand the flow of system.
  • It helps the user to solve the problems such as troubleshooting and helps the manager to take better final decisions of the organization system.
  • It provides better control to the internal or external working of the system.

Types of Feasibilities :

Economic Feasibility :

  • It is evaluating the effectiveness of candidate system by using cost/benefit analysis method.
  • It demonstrates the net benefit from the candidate system in terms of benefits and costs to the organization.
  • The main aim of Economic Feasibility Analysis (EFS) is to estimate the economic requirements of candidate system before investments funds are committed to proposal.
  • It prefers the alternative which will maximize the net worth of organization by earliest and highest return of funds along with lowest level of risk involved in developing the candidate system.

Technical Feasibility

  • It investigates the technical feasibility of each implementation alternative.
  • It analyzes and determines whether the solution can be supported by existing technology or not.
  • The analyst determines whether current technical resources be upgraded or added it that fulfill the new requirements.
  • It ensures that the candidate system provides appropriate responses to what extent it can support the technical enhancement.

Operational Feasibility :

  • It determines whether the system is operating effectively once it is developed and implemented.
  • It ensures that the management should support the proposed system and its working feasible in the current organizational environment.
  • It analyzes whether the users will be affected and they accept the modified or new business methods that affect the possible system benefits.
  • It also ensures that the computer resources and network architecture of candidate system are workable.

Behavioral Feasibility :

  • It evaluates and estimates the user attitude or behavior towards the development of new system.
  • It helps in determining if the system requires special effort to educate, retrain, transfer, and changes in employee’s job status on new ways of conducting business.

Schedule Feasibility :

  • It ensures that the project should be completed within given time constraint or schedule.
  • It also verifies and validates whether the deadlines of project are reasonable or not.

The word System is derived from Greek word Systema, which means an organized relationship between any set of components to achieve some common cause or objective.

A system is “an orderly grouping of interdependent components linked together according to a plan to achieve a specific goal.”

Structured Analysis Tools : During Structured Analysis, various tools and techniques are used for system development. They are −

  • Data Flow Diagrams.
  • Data Dictionary.
  • Decision Trees.
  • Decision Tables.
  • Structured English.
  • Pseudocode.

Joint Application Development (JAD) : It is a new technique developed by IBM which brings owners, users, analysts, designers, and builders to define and design the system using organized and intensive workshops. JAD trained analyst act as facilitator for workshop who has some specialized skills.

Advantages of JAD

  • It saves time and cost by replacing months of traditional interviews and follow-up meetings.
  • It is useful in organizational culture which supports joint problem solving.
  • Fosters formal relationships among multiple levels of employees.
  • It can lead to development of design creatively.
  • It Allows rapid development and improves ownership of information system.

A requirement is a vital feature of a new system which may include processing or capturing of data, controlling the activities of business, producing information and supporting the management.

Requirements determination involves studying the existing system and gathering details to find out what are the requirements, how it works, and where improvements should be made.

File Organization : It describes how records are stored within a file.There are four file organization methods.

  1. Serial :  Records are stored in chronological order (in order as they are input or occur). Examples − Recording of telephone charges, ATM transactions, Telephone queues.
  2. Sequential :  Records are stored in order based on a key field which contains a value that uniquely identifies a record. Examples − Phone directories.
  3. Direct (relative) : Each record is stored based on a physical address or location on the device. Address is calculated from the value stored in the record’s key field. Randomizing routine or hashing algorithm does the conversion.
  4. Indexed : Records can be processed both sequentially and non-sequentially using indexes.

It comes to System Design, there are following four main documentations :

  1. Program documentation.
  2. System documentation.
  3. Operations documentation.
  4. User documentation.

Review of Records, Procedures, and Forms : Review of existing records, procedures, and forms helps to seek insight into a system which describes the current system capabilities, its operations, or activities.

Advantages : 

  • It helps user to gain some knowledge about the organization or operations by themselves before they impose upon others.
  • It helps in documenting current operations within short span of time as the procedure manuals and forms describe the format and functions of present system.
  • It can provide a clear understanding about the transactions that are handled in the organization, identifying input for processing, and evaluating performance.
  • It can help an analyst to understand the system in terms of the operations that must be supported.
  • It describes the problem, its affected parts, and the proposed solution.