System

1
System

• A System is a set of interrelated elements that
  collectively work together to achieve some common
  purpose or Goal. e.g.
• Communication System.
• Computer System.
• Business / Firm.

2
Systems Attribute

1. Elements of the System.- These are the units
   within the system which interact with each other
   to produce desire results. These may be tangible
   objects, abstract concepts (intangible) or an
   event.
2. Boundary of the System.- Boundary is the area
   that separates one system from another. Any thing
   within the boundary is part of the
   system(element). It is a filter of inputs and
   outputs between system and surroundings.
3. Surroundings of the System.- Any thing outside
   the boundary of the system that influences the
   operation of system and cannot be directly
   controlled by the system.
4. Input of the System.- These are the energies
   taken into the system. Results/Outputs are
   produced after processing of these inputs. e.g.
   Electric Current, Computer Program..
5. Output of a System.- These are the energies
   discharged from the system into the environment.
   e.g. Financial Statements are output of an
   Accounting Information System(AIS).
6. Interface.- It is the medium for transporting the
   output from one system into another system as
   input.

3
Open System

• A system which accepts input from the environment
  and returns output to its surroundings. Almost
  all systems are open in nature.

Close System
Close Systems do not interact with environment.
It means that no inputs are fed into systems and
no outputs are returned.
4
Why we replace existing Systems

• New Systems (CBIS) frequently replace existing
  manual systems and new systems may themselves be
  replaced after sometime due to introduction of
  new Technologies/Applications. Some of the
  reasons why users and MIS professionals consider
  an existing system to be inadequate are-
• ? Existing System does not support business
  objectives and strategies efficiently.
• ? It does not satisfy the needs and requirements
  of users.
• ? It has inadequate system controls.
• ? It has software that is unstructured and
  difficult to maintain.
• ? Less use of modern technologies.
• ? It contains various flaws and errors in its
  design.
• ? It is poorly documented and difficult to use.

5
Successful MIS

• In order to develop a successful System different
  methods/techniques are used. These methods enable
  the professionals to build information system
  that not only satisfy the user's requirements but
  also are delivered in time and within a budget.
• High level of user involvement are present
  throughout the system development process.
• Project management techniques are used to
  implement systems plan.
• Alternative system designs are developed and
  critically evaluated prior to committing to final
  design, technology and software.

6
Successful MIS

• Structured program designing and coding is used.
• Clear, complete and accurate documentation for
  the new system is generated throughout the system
  development process.
• System implementation and user training are
  carefully planned and coordinated.
• Post implementation reviews are conducted to
  ensure that user and management needs were met.
• New systems are designed for easy maintenance.
• No System is guaranteed of success but if above
  points are considered, chances that users and
  mangers will satisfy should increase.

7
SYSTEM DEVELOPMENT LIFE CYCLE (SDLC)

• The process of replacing the old system by the
  new one take in a series of stages and the whole
  process is called System Development Life Cycle.
  It comprises the following stages
• Preliminary Investigation of the System.
• Detailed System Analysis or Requirement Analysis.
• System Design.
• System Acquisition and System Development.
• System Implementation and Evaluation.
• System Maintenance.

8
What is SDLC.

•  1. PRELIMINARY INVESTIGATION OF SYSTEM.
• Initial study/system study.
• Problem identification.
• Feasibility study/report.
•  2. REQUIREMENT ANALYSIS
• Detail system study.
• System analysis.
• Preparation of statement of requirements.
• 3. SYSTEM DESIGN.
• Review of TORs (Term of references).
• Specification of proposed system.
• User interface designing. (Screen design /
  Reports layout etc.)
• Reporting to management about 3rd phase.

9
. What is SDLC

• 4. SYSTEM ACQUISITION AND DEVELOPMENT.
• Acquisition of hardware and software.
• Software Development.
• Documentation.
• 5. SYSTEM IMPLEMENTATION.
• System testing.
• User training.
• Implementation method.
• Post implementation reviews.
• 6. SYSTEM MAINTENANCE.

10
Preliminary Investigation

• Preliminary Investigation of system
• First phases of SDLC start when a user found some
  problem/difficulties in the operation of existing
  system or management decides to change the
  current system to met the changing requirement.
  Normally consultant are hired to observe/study
  the existing system them recommend a propose
  system which fulfill all requirement. It consist
  of different sub activities.
• The preliminary investigation is the first step
  in system development. After a user need or
  opportunity is identified, a system analyst
  determines if a new or modified system is
  necessary. Preliminary Investigation is also
  known as project feasibility study.

11
Preliminary Investigation

• The main objective of this phase (step) is to
  determine whether or not work on a new/modified
  system is capable of being accomplished.
  Following areas are considered to evaluate the
  feasibility of a project.
• Technical feasibility.
• Operational feasibility.
• Economic feasibility.
• Schedule feasibility.

12
Preliminary Investigation

• The main task performed by the system analyst in
  this step are-
• Identifying and defining the problem and its back
  ground.
• Determining the size of the development effort
  involved.
• Recommendations of different possible solution.
• Cost and Benefits of each option.
• Result of these tasks are listed in a report
  known as Project Feasibility Report and will
  be sent to steering committee/Top management for
  further consideration and approval.

13
Requirements Analysis (System Analysis).

• If management decides to continue developing the
  system after reading the Systems Analysts report
  (Project feasibility Report), the second phase of
  development begins. In traditional approach, the
  full requirement analysis is performed before
  system design begins. User typically sign a
  document at the end of this phase, confirming the
  requirements identified by System Analyst. In
  prototype approach, requirement analysis and
  system design phases proceed in simultaneously.
  In requirement analysis phase following
  activities are performed-
• Users requirements are determined in detail.
• Existing system is studied in depth to analyze
  the data and its processing.
• Preparation of statement of requirements.

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.Requirements Analysis (System Analysis)

• The systems analyst will explore a no. of routes
  and use a variety of methods to establish a full
  picture of the existing system. Following
  techniques/methods will be used to collect data
  about the existing system in this phase-
• Documents.
• Questionnaires.
• Interviews.
• Observation.
• In system analysis and system design phase Data
  Flow Diagrams (DFD) and system flow charts are
  used to represent the movement of data in an
  organization.
• The last step of this phase is to report finding
  to management. This includes a recommendation
  from the list of alternative solution, an
  assessment of costs and benefits and a schedule
  covering future system activities. (Design,
  Development Acquisition and implementation).

15
System Design

• System design consists, generally, of three
  activities reviewing informational and
  functional requirements, developing a model of
  the new system, and reporting the results to
  management. Developing a model of the new system
  comprises the bulk of system design.
• When designing a new system, Systems Analysts
  determine, at both the logical and physical
  levels, the components of the system in the areas
  of input, output, processing, storage,
  procedures, and personnel. A logical description
  of information describes how elements of the
  system relate to each other - without mention,
  perhaps, of specific hardware deceives or
  software packages. A physical description, in
  contrast, identifies specific devices or
  products.
• The impact of systems software and computing
  hardware must also be assessed in the design
  process. Some issues to consider are the types of
  computations involved, whether or not
  telecommunication or real-time processing is
  necessary, and throughput (which relates to how
  much work a given computer system can do in a
  given amount of time).
• After system design activities are completed,
  they are reviewed by users and reported to
  management.

16
System Acquisition

• After the system design details are resolved,
  such resource needs as specific types of
  hardware, software, and services are determined.
  Subsequently, choices are made regarding which
  products to buy or lease from which vendors.
  These activities are part of system acquisition.

System Development

• In this stage following activities are
  performed-
• Establish a Project Development Schedule
• Produce Specification for each Programme to be
  Developed
• Coding, Testing and Debugging of each Programme.
• Create the Documentation for the System

17
System Implementation

• After development and successful testing of the
  system, the next stage is to put it into action,
  i.e. system implementation. Usually there are
  four distinct alternatives approaches are used to
  implement a new system
• Direct Implementation
• Parallel Implementation
• Pilot Implementation
• Phased Implementation

System Maintenance

• Once the system has been introduced successfully,
  it does not mean the end of the systems analysts
  work. The system has to be maintained, added to,
  adapted and amended in the light of subsequent
  developments. These may be due to
• Error Elimination
• New Developments in Technology
• Other External Circumstances
• After implementation, the system is maintained,
  it is modified to adapt to changing user and
  business needs so that the system can be useful
  to the organization for as long as possible.

18
APPROACHES TO SYSTEM DEVELOPMENT

• Approaches to systems development are often
  classified according to how the five systems
  development activities are carried out or whether
  the development efforts are top-down or
  bottom-up. The first of these classifications
  divides systems development process into three
  basic approaches the traditional approach,
  prototyping approaches, and end-user development.

Traditional Approach

• In the traditional approach, developmental
  activities are followed in strict sequence, one
  after the other. This approach is criticized
  because it is often difficult for users to
  formulate their needs in advance. This approach
  can be used in following circumstances.
• User have significant experience with the type of
  system to be designed.
• Many important features can be readily identified
  before development begins.
• Data requirements can be identified in advance.
• Management requires a comprehensive picture of
  the new system before giving approval.
• The development staff is not experienced with
  prototyping tools.

19
Prototyping Approaches

• With prototyping approaches, a small or pilot
  version of the system--called a prototype-- is
  developed. Users work with the prototype, and
  feedback provided to the systems analyst leads to
  further prototype refinements or enhancements.
  This process of gradually improving the prototype
  through iterative user feedback continues until a
  final, acceptable system is developed. Normally
  this approach is used in following circumstances.
• User do not have a feel for the information or
  system capabilities they require.
• User needs are changing rapidly.
• Users have little experience with the type of
  system under development
• The risk associated with delivering the wrong
  system is high.
• The way users will react to the new system is an
  important development variable.
• Many alternative design strategies must be
  tested.
• The system must be developed quickly and at the
  lowest possible cost.

20
End-user Development Approach

• With end-user development, the end-user is
  responsible for developing the system. The
  end-user may select a traditional type of
  approach, a prototyping approach, or an intuitive
  approach. It is used in following circumstances.
• The system under development is local rather than
  enterprise-wide.
• The system under development is inexpensive.
• A suitable environment of end-user development
  tools and professional expertise is available.
• Standards exist to minimize divergent efforts by
  the end-users and other dangers to the
  organization.
• High levels of security are not necessary for the
  system being developed.
• The system under development involves numerous
  customized queries and reports.
• The system under development can easily be built
  and supported by the end-user.
• The system under development does not involve
  high-volume transaction processing.
• The development time is short and cannot be
  accommodated by the MIS department (possibly
  because of a huge application backlog).
• The user must be heavily involved in the
  development process.
• Top-down systems development views the
  organization's needs from a strategic
  perspective, and a new system is developed to
  meet that perspective. Bottom-up systems
  development looks at the existing organizational
  systems and tries to meet new systems needs
  within the constraints posed by those existing
  systems. In most cases, a combination of top-down
  and bottom-up approaches is used.

21
Documentation

• Documentation is the term used to describe all
  types of written instructions associated with
  using, operating, developing or maintaining a
  computer system. The primary objective of
  documentation must be to provide easy-to-flow,
  unambiguous, user friendly instructions and
  explanations. Good documentation is highly
  important to the success of any system. Good
  documentation however, is very often under rated.
  It is also true that the skills required to
  produce a good documentation is quite different
  from those required for systems analysis and
  design and is rare.
• Many analysts treat documentation rather casually
  and wait until the entire system is almost
  finished to begin preparing it. The documentation
  process is thus rushed to meet the deadline and a
  poor documentation is the result. Luckily, modern
  4th GLS have built in facility to produce part of
  the documentation while systems development is
  taking place.
• Documentation can broadly be classified as
• ? User Manual
• ? Systems/Technical Manual

22
User Manual

• User documentation consists of either a written
  or disk tutorial and a reference manual. The
  tutorial is designed to get the user started with
  using the system and help him to solve the many
  problems that may crop up while he is trying to
  gain command over the use of the system. The
  reference manual, intended for advanced users, is
  really the bible for the package. If the user
  cannot figure out how a command works, he may
  consult the manual to solve the problem.

System Manual

• Systems manuals are actually meant for the DP
  professionals, the systems analyst and
  programmers who may be required to run the system
  and make amendments and additions to it later on.
  The Systems manual comprises of the following
• Systems Specification - which will include all of
  the materials that are necessary to show how a
  particular system operates. This includes system
  requirements, diagrams, such as data flow
  diagrams or systems flow charts, written
  narratives of job descriptions and so forth.
• Program listing - the manual will include listing
  of all the programs source codes.
• An English narrative describing what the program
  and programs modules are supposed to do together
  with program flowcharts.
• Files - the names and descriptions of all the
  files used in the system together with their
  structures, i.e. the names and descriptions of
  the variables used. A cross reference of all
  files called by each program is also included.
• Forms Layout - a complete list of all the forms
  for inputs and outputs used by the system
  together with their layouts.

23
Implementation Techniques.

• Direct Implementation
• Using this method of implementation, the old
  system is completely replaced by the new system
  in one move. While this method is comparatively
  cheap it is risky (system or program corrections
  are difficult while the system has to remain
  operational). The new system should be introduced
  during slack periods. This requires a great deal
  of effort and there might be considerable
  disruption.
• Parallel Implementation
• This is a form of implementation whereby the old
  and new systems are run in parallel for a period
  of time. There may be some errors in the new
  system ,this method provides a degree of safety.
  However, if there are differences between the two
  systems cross-checking may be difficult.
  Furthermore, there is a delay in the actual
  implementation of the new system, a possible
  indication of lack of confidence in the new
  system, and a need for more staff to cope with
  both systems running in parallel. As far as the
  company is concerned, this is likely to prove too
  expensive and unwieldy given the volume of data
  processed.

24
. Implementation Techniques

• Pilot Implementation
• This is cheaper and easier to control than
  parallel running, and provides a greater degree
  of safety than does a direct changeover. In this
  approach a complete logical part of the whole
  system file is chosen and run as a unit on the
  new system. If that is shown to be working well
  the remaining parts are then transferred.
  Gradually the whole system can be transferred in
  this piecemeal fashion. Two systems have to be
  controlled and additional staff, as well as a
  longer period for implementation, may be
  required. However, this would seem to be an
  appropriate option for the company.
• Phased Implementation
• This is particularly suitable for large projects.
  It is a process of changing over from the old
  system to the new one in segments for example on
  a department by department basis. This may be
  done either by a series of periods of parallel
  running, or by a series of direct changeovers. In
  the former case, instead of running two complete
  systems (old and new) in parallel in order to
  compare the results of living processing on the
  new system with those generated by the old, only
  a portion of the data is run in parallel, e.g.
  for one department only. In the latter case, the
  same considerations apply as for an
  organization-wide direct changeover.
• Where this approach is adopted care must be taken
  to control any systems amendments incorporated in
  the later phases in order to ensure that the
  overall system remains totally compatible.

25
What is SDLC.

• In order to develop a new CBIS, consultants have
  to perform a no. of activities. Collection of
  activities to be performed during system
  development is called SDLC. It include following
  phases.
•  1. PRELIMINARY INVESTIGATION OF SYSTEM.
• Initial study/system study.
• Problem identification.
• Feasibility study/report.
•  2. REQUIREMENT ANALYSIS
• Detail system study.
• System analyses.
• Preparation of statement of requirements.
• 3. SYSTEM DESIGN.
• Review of TORs (Term of references).
• Specification of proposed system.
• User interface designing. (Screen design /
  Reports layout etc.)
• Reporting to management about 3rd phase.

26
. What is SDLC

• 4. SYSTEM DEVELOPMENT.
• Acquisition of hardware and software.
• Software Development.
• Documentation.
• 5. SYSTEM IMPLEMENTATION.
• System testing.
• User training.
• Implementation method.
• Post implementation reviews.
• 6. SYSTEM MAINTENANCE.
• Preliminary Investigation of system
• First phases of SDLC start when a user found some
  problem/difficulties in the operation of existing
  system or management decides to change the
  current system to met the changing requirement.
  Normally consultant are hired to observe/study
  the existing system them recommend a propose
  system which fulfill all requirement. It consist
  of different sub activities.

27
INITIAL STUDY.

• In this sub activities consultant have to observe
  the working of system to find out its working and
  objective (short term as well as long term).
  During initial study consultant have to
  locate/indicate factor which are creating
  problems in the working/operation of current
  system. These sub activities called
  identification of problem in the existing system.
• It is the responsibility of consultant to
  recommend more than one procedure/alternative to
  solve/remove identified problem. Composition of
  each option is made on bases of benefits,
  limitation and cost estimate. Propose solution
  are evaluated to check their suitability/feasibili
  ty with respect to following factors.
• Technical feasibility.
• Operational feasibility.
• Economic feasibility.
• Organization feasibility.

28
. INITIAL STUDY

• At the end of 1st phase reports is prepared by
  consultant for the consideration/approval of top
  management about the development of new system.
• This report contains following information -
• Introduction of end user organization.
• Introduction of consultant.
• Brief description of the system/project being
  studied.
• Problem area of existing system.
• Different alternative to solved remove the
  problem.
• Comparison of each option.
• Recommendation of consultant.

29
REQUIRMENT ANALYSES.

• 2ND phase of SDLC starts when top
  management/project steering committee decide to
  continue the development of new system after
  evaluating the feasibility report prepare in
  first phase. Normally system analysts are deputed
  by consultant to determine the detail requirement
  of end user organization.
• Following sub activities have to be perform by
  system analyst during this phase.
• In this sub activities the end user organization
  is studied in depth understand the data and
  processing requirement of organization. For this
  purpose system analyst have to use different data
  collections techniques some of them are -
• By observing facts.
• By conducting interviews.
• By floating questioner.
• By reading office manual.

30
.REQUIRMENT ANALYSES

• After collecting necessary information about data
  and data processing requirement of existing
  system, it is the responsibility of system
  analyst to create a relation among these
  requirements. It helps the system analyst to
  determine the requirement of organization with
  respect to propose system.
• Different type of data analysis tools are used by
  system analyst during this phase.
• Data flow diagram DFD.
• System flow charts.
• Organogram (Organizational chart).
• Decision Table.
• Decision tree.
• At the end of 2nd phase system analyst have to
  prepare a report/statement describing all
  requirement of end user organization. This report
  act as agreement between consultant and
  organization. Both parties have to follow these
  TORS. It means that consultant have to develop a
  system which fulfill all requirements describe in
  TORs according to specified time schedule. End
  user organization have to pay extra amount if the
  add some requirement latest stages.

31
System Design.

• In the 3rd phase of SDLC system analyst/system
  designer have to prepare the specification
  (logical model) of proposed system. These
  specification are based on the requirement
  identified in 2nd phase.
• It is better to review all identified requirement
  before preparing the specification of proposed
  system. It is easier to add additional
  requirement at this stage.
• What type of data processing are made in the
  propose system and what type of devices are
  required in propose system. These type of
  question are assume by SA/SD during this
  activities. What type of procedure are used in
  proposed system to fulfill the requirement or
  achieve defined targets. Almost all paper work
  about the propose system is finalizes in the face.

32
. System Design

• In this sub activities different issue regarding
  user interface are design by SA/SD for example -
• Screen design/form designing.
• Lay out of report.
• Style of message / dialogue boxes.
• File designing (Structure of tables, field size,
  field type and relation among table).
• A set of system design tools used in this phase
  which are E.
• ERD entity relationship diagram.
• HIPO charts (hierarchical input processing output
  ).
• Structured English.
• Pseudo code
• Algorithms.
• Program flow chart.
• At the end of 3rd phase a consolidated report
  prepare for Management to inform the current
  status of system development and to direct the
  system developer about system designing phases.

33
Why we replace a new system with existing system?

• There are three reasons
• According to changing environment there may be a
  chance that the existing system doesnt fulfill
  all requirements of a n organization.
• Introduction of modern / latest technologies.
• There may be chance that existing system produce
  incorrect delayed results.
• Programs of existing systems are difficult to
  modify /maintain due to un-structured programming
  poor documentation.

34
System Development Techniques.

• 1. WATER FALL MODEL-
• It is also known as traditional approach of
  system development process. It this model all
  activities / phases of SDLC are performed in
  sequential order (top to bottom ). This approach
  of system development requires more development
  time as compared to other approaches. It is the
  most effective system developed according to
  fulfillment of requirements due to the season
  that all phase are perfumed in a very detailed
  manner.
• 2. RAD RAPID APPLICATION DEVELOPMENT-
• This technique of system development is
  introduced to seduce the system development time.
  In this model more than one activities / phases
  are performed in parallel. This technique of
  system development use different methods of
  developing new system.
• Prototyping
• Incremental model.
• 3. PROTOTYPING-
• It is a type of RAD. It the first instance
  project manager /system analyst develop a very
  sough model of a new system and handed over to
  the uses\r for its input. This sough model is
  changed / modified repeatedly acceding to user
  requirements/ input.

35
. System Development Techniques

• 4. JOINT APPLICATION DEVELOPMENT (JAD)-
• A technique developed by the professional of IBM.
  In this technique a team / work group of
  consultants, IT Professionals and end-users is
  selected and assigned the development of new
  system. This work group is mere effective to
  determine the requirement of new system and to
  develop an acceptable system.
• 5. INCREMENTAL SYSTEM DEVELOPMENT MODEL-
• In this model first phase of SDLC is again
  performed after the completion of last phase.
  Using this approach a new system become more
  acceptable for an organization for a longer
  period.
• 6. SPIRAL MODEL-
• It is also an incremental model in which
  activities of SDLC are performed repeatedly to
  get an acceptable system.
• 7. OBJECT ORIENTED SYSTEM DEVELOPMENT-
• It is also known as component based system
  development. This technique uses the object
  oriented techniques for system development. First
  of all main abject of new systems are defined
  /created and them these object are combined
  effectively to develop a system which fulfills
  all requirement of an organization.