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Questions and Answers
Which of the following is NOT a key step in the systems development life cycle (SDLC)?
Which of the following is NOT a key step in the systems development life cycle (SDLC)?
The main goal of systems analysis and design is to develop new hardware components.
The main goal of systems analysis and design is to develop new hardware components.
False
What is the primary role of a systems analyst in the development of information systems?
What is the primary role of a systems analyst in the development of information systems?
To identify, analyze, design, and implement software solutions that meet organizational needs.
The process of maintenance in an information system should be controlled by the __________.
The process of maintenance in an information system should be controlled by the __________.
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Match the following components with their descriptions:
Match the following components with their descriptions:
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Which phase of the SDLC involves preparing diagrams and estimates of impact when a change is suggested?
Which phase of the SDLC involves preparing diagrams and estimates of impact when a change is suggested?
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Integrated Circuits (ICs) are associated with the first generation of computers.
Integrated Circuits (ICs) are associated with the first generation of computers.
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Which of the following is NOT a phase in the Systems Development Life Cycle (SDLC)?
Which of the following is NOT a phase in the Systems Development Life Cycle (SDLC)?
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What does SDLC stand for?
What does SDLC stand for?
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The Systems Development Life Cycle (SDLC) is always a strictly linear process.
The Systems Development Life Cycle (SDLC) is always a strictly linear process.
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What is the primary purpose of the Systems Development Life Cycle (SDLC)?
What is the primary purpose of the Systems Development Life Cycle (SDLC)?
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In the SDLC, the first step involves having an ________ for an information system.
In the SDLC, the first step involves having an ________ for an information system.
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Match the following SDLC phases with their descriptions:
Match the following SDLC phases with their descriptions:
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Which statement about life cycles is correct?
Which statement about life cycles is correct?
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The SDLC allows for the repetition of phases until a satisfactory system is achieved.
The SDLC allows for the repetition of phases until a satisfactory system is achieved.
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What does the term 'spiral model' in the context of SDLC imply?
What does the term 'spiral model' in the context of SDLC imply?
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What is the first phase in the Systems Development Life Cycle (SDLC)?
What is the first phase in the Systems Development Life Cycle (SDLC)?
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The SDLC model is only applicable to medium-to-large corporations.
The SDLC model is only applicable to medium-to-large corporations.
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What are the two primary activities during the systems planning and selection phase?
What are the two primary activities during the systems planning and selection phase?
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The circular nature of the life-cycle diagram illustrates that the end of one system leads to the beginning of another project, demonstrating the concept of __________.
The circular nature of the life-cycle diagram illustrates that the end of one system leads to the beginning of another project, demonstrating the concept of __________.
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Which of the following is NOT a reason for requesting a new information system?
Which of the following is NOT a reason for requesting a new information system?
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In every SDLC, milestone deliverables are only reviewed by the project team members.
In every SDLC, milestone deliverables are only reviewed by the project team members.
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During the systems planning and selection phase, what does a systems analyst create based on the identified needs?
During the systems planning and selection phase, what does a systems analyst create based on the identified needs?
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Study Notes
Information System Analysis and Design COSC 327
- This course covers general system concepts.
- It includes an introduction to systems.
- The course covers information system components.
- Different types of information systems are discussed.
- Systems development life cycles (SDLC) are examined, including linear/waterfall, prototyping, and spiral methods.
- Preliminary investigation and feasibility activities are part of the course.
- Analyzing requirements, structured analysis, Data Flow Diagrams (DFD), process description tools (like decision tables/trees), and object-oriented system analysis (with an overview of UML) are key topics.
- System design principles, including output design (e.g., reports, screen outputs, tapes), input design (e.g., data entry screens, help screens), and general guidelines, are discussed.
- Real-life case studies are used to apply SDLC principles and techniques.
- Prerequisite courses for this class are COSC 202 and INSY 241.
- A textbook, "Essentials of System Analysis and Design" by Valacich et al. (Pearson, 2012) is used.
General Introduction to Systems
- Systems are designed to solve problems.
- The systems approach is a structured way of handling a problem.
- System Analysis and Design focuses primarily on software development.
Defining a System
- A system is a collection of components working together to achieve a goal.
- Every system has input, processing, and output.
General System Interconnection and Objectivity
- Systems are interconnected, like political, economic, and educational systems.
- A system's objective is to produce an output from processed input.
Definition of a System (cont.)
- Systems are commonly encountered in daily life.
- A system's work is often part of a larger system.
Attributes of System Viability
- Reliability: The probability a system will perform its intended function without failure in a specific period.
- Product Availability: The likelihood of an item being usable when required. Measured as MTBF/(MTBF + MTTR), where MTBF is Mean Time Between Failures and MTTR is Mean Time To Repair.
- Product Dependability: A measure of a product's ability to operate and perform functions at any random time.
- Product Quality: A product's overall performance from customer/user feedback after significant use.
Common Types of Systems
- Systems are categorized into natural and man-made systems.
- Natural systems include physical (e.g., galaxies, rivers) and living systems (e.g., animals, plants).
- Man-made systems can be social (laws, customs), conceptual (disciplined ideas), transportation (highways, canals), communication (telephone, internet), manufacturing (factories, assembly lines), and financial (accounting, inventory).
19 Properties of Familiar Living Systems
- A list of 19 noteworthy properties that can apply to how we manage man-made systems.
Definition of a System (cont.)
- A structured set of interacting or interdependent items.
- A systematic procedure or process.
- A unified set of doctrines, ideas, principles to explain a systematic whole.
- An ordered arrangement or pattern.
- An organized society or social situation.
Automated Systems
- Automated systems are man-made systems controlled by one or more computers.
- Common components include hardware (CPUs, disks, terminals), software (operating systems, database systems), peopleware, data, and procedures.
- Categorization by application is not useful; common techniques are applicable to different applications.
- Batch systems handle information sequentially.
- Real-time systems process information quickly to influence the current environment, examples include air-line ticket reservation and low-level billing systems.
- Online systems accept input directly from where it's created.
Types of Automated Systems (cont.)
- Decision-support systems help managers make intelligent decisions.
- Knowledge-based systems have the goal of imitating human intelligence.
General Systems Principles
- Specialized systems have less adaptability to various situations.
- General systems have less optimization for a specific situation, but greater adaptability.
- Larger systems need greater resources for maintenance.
- Systems are always part of (or partitioned into) larger systems.
- Systems grow through time.
Computing in the Early Days
- Early computers were perceived as complex and intimidating.
- Modern computers are more user-friendly.
Components of Information Technology
- Hardware
- Software
- Peopleware/Warmware
- Procedures
- Data
What Is a Computer?
- A general-purpose machine that processes data based on stored instructions.
- Attached equipment is called hardware.
- Instructions are software.
Generations of Computers
- First generation: vacuum tubes (ENIAC, EDVAC, UNIVAC)
- Second generation: transistors (Honeywell 800, IBM)
- Third generation: integrated circuits (ICs) (IBM/360)
- Fourth generation: Large Scale Integration (LSI) (pocket calculators, digital watches, PCs)
- Fifth generation: Emphasis on application of computers, not on the electronic technology behind them (industrial robots).
Computer Structure, Processor Architecture, Fabrication, and Operation
- Hardware refers to the physical components of a computer system.
- Computer hardware is typically divided into input, output, and storage components.
- Microprocessors (CPU) are the central processing units.
- Wires or circuitry called a bus connect components to the CPU.
Software
- Software is a set of instructions that tells the computer how to use the hardware.
- Programs such as word processors or video games are common forms of software.
- Software for managing how hardware is used is called the Basic Input Output System (BIOS).
- Microprocessors have both hardware and software aspects.
Input Devices
- Input devices allow users to provide data and instructions to the computer.
- Examples include keyboards, mice, microphones, scanners, cameras, and digital pens.
Processing Devices: The Central Processing Unit (CPU)
- The CPU processes data and converts it into useful information.
- The CPU is the control center and brain of the computer.
- Four main components: The control unit (CU), Arithmetic Logical Unit (ALU), Memory Unit, and BUSES.
CPU: Control Unit (CU)
- The CU controls the computer's activities.
- It directs signals and data between the main memory and ALU, and between the CPU and input/output devices.
CPU: Arithmetic and Logic Unit (ALU)
- The ALU performs arithmetic and logical operations.
CPU: Registers
- Registers are temporary storage locations within the CPU that hold data and instructions while they're in use.
Memory Hierarchy
- Registers, SRAM, L1 Cache, SRAM, L2 Cache, DRAM, DDR, Rambus, SDRAM, hard disk, tape, CDs, and DVDs.
CPU: Buses
- Buses are electrical pathways that transmit data between computer components.
- Three types of buses: Data Bus, Address Bus, and Control Bus
- An Expansion Bus connects the processor to peripheral devices.
Processor
- The processor is the brain of the computer, processing instructions.
- The three steps are fetching instructions, decoding instructions, and executing instructions.
What is a Processor?
- Integrated chips with millions of electronic components (like transistors and resistors).
- The CPU of a microcomputer is a microprocessor.
- Processor and main memory are held on a single board called a motherboard.
Memory
- Memory is a computer's ability to store data temporarily or permanently.
- Primary memory (RAM) is for temporary storage and volatile; lost when power is off.
- Secondary memory (e.g., hard disk) stores data permanently and is non-volatile.
Main Memory
- Also known as primary memory
- A designated working area for temporarily holding data and instructions.
- Data is lost when the computer is turned off.
Primary Memory (RAM and ROM)
- Random Access Memory (RAM): used to store programs and data that are currently running.
- Read-Only Memory (ROM): data permanently stored from the manufacturing process, used to load a basic program.
RAM - Random Access Memory
- Stores application information and data.
- Data is lost when power is off.
- Different types include SRAM (Static RAM, less expensive and slower), and DRAM (Dynamic RAM, higher speed).
ROM (Read Only Memory)
- Non-volatile storage used for storing permanent instructions (e.g. programs).
- Several kinds of ROM, including PROM (programmable ROM), EPROM (Erasable PROM), EEPROM (Electrically erasable PROM).
Main Memory (cont.)
- Main memory is divided into addressable storage units called bytes.
- Each byte can hold a character or code for something (part of a picture, sound, or instruction).
Storage Devices
- Storage devices are used to store data permanently.
- Types include Magnetic Tape, Hard Disk, Floppy Disk, CD-ROM, CD-RW, DVD-ROM, and DVD-RW.
Disk Storage
- Auxiliary storage, also called secondary or external memory.
- This commonly involves disk-based storage (hard disk drives).
Secondary Storage (cont.)
- Necessary because main memory is temporary storage and limited.
- Benefits include space, reliability, convenience, and economic efficiency
Storage Devices (cont.)
- Common consumer electronic devices can store data -- the format may or may not be intended for data.
Output Devices
- Output devices display information for users to see and use.
- Examples include display monitors, printers, and audio output devices.
Types of Monitors
- CRT (cathode ray tube): used electron beams to "paint images"
- LCD (liquid crystal display): uses flat panel technology.
- Gas Plasma: thin panel technology with gas between layers.
- LED (light emitting diodes): flat panels using light-emitting diodes.
- Size: standard sizes (14”, 15”, 17”, 19”, 21”)
Output Devices: Printers
- Output devices convert electronic information to paper copies.
- Types include impact printers (dot matrix, line printer, daisy wheel) and non-impact printers (inkjet, laser, thermal, photo printer, and plotter).
Output Devices: Audio Output
- Audio output devices deliver sound.
- Examples include speakers and CD players.
Optical Devices
- Devices that project or cast images onto a screen.
- Holography is a technique used to produce three-dimensional images.
Computer Chipset
- The chipset is the "brain" of a personal computer system.
- Connects components, like the CPU, RAM and storage to the network and peripherals through a bus system, enabling smooth data transmission
Introduction to Systems Analysis and Design
- The key to business success is gathering, organizing, and interpreting information.
- System analysis and design is a proven process for improving business organizations.
- The primary person involved in this process is the systems analyst.
System Life Cycle
- System lifecycle is the organized process of developing and maintaining a system.
- The lifecycle is a collection of activities organized together.
- The lifecycle is also described as the software development lifecycle (SDLC).
8-Phase SDLC
- System study
- Feasibility study
- System analysis
- System design
- Coding
- Testing
- Implementation
- Maintenance
Phases of System Development Life Cycle (cont.)
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(a) System Study: Determining the scope of an organizational system (the preliminary survey, the detailed analysis)
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(b) Feasibility Study: A test of the proposed system’s practicality in regards to technical, economic, personnel, operational, legal considerations,
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(c) Systems Analysis: Determines the various processes of the existing system, data gathering, and defining user requirements
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(d) System Design: Converting user needs into a detailed architectural design;
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(e) Coding: Translates the design into a programming language,
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(f) Testing: Testing the system thoroughly to find and correct any errors.
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(g) Implementation: Putting the new system into operation use & training the users.
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(h): Maintenance: The modification and ongoing support of the ongoing system
Defining a Project's Scope
- The project/system needs agreement on the following questions:
- What problem does the project address?
- What are the results to be achieved?
- What needs to be done?
- How will success be measured?
- How will the project's completion be determined?
- Identify alternative solutions to the problem.
Assessing Project Feasibility
- A required step for new information system projects and considering budgets and deadlines
- The process of determining a project's likelihood of success based on factors such as economic, operational, technical, schedule, legal and contractual, and political factors.
Modeling
- Mathematical modeling: encoding a real-world system into a mathematical model that can be used for analysis or design.
- Purpose of mathematical modeling -- understand a real-world system.
- Important in biological sciences for hypothesis testing and determining the practicality of new experiments.
- Simulation modeling: a way to analyze the real system's behavior by executing a computerized model instead of fully analyzing the system.
Tools Supporting Analysis: Data Flow Diagram (DFD)
- DFDs are a popular tool representing data flow and processes.
- Types: High-level (shows the major functions and processes), and detailed (shows the specifics of processes within each function)
- Components: External entities (sources or destinations of information), processes (actions on information), data stores (repositories for information), and data flows (the movement of data between processes and data stores)
Tools Supporting Analysis: Entity-Relationship Diagram (ERD)
- ERDs are used to diagram relationships between the items/data in a system.
- Components: Entities (subject, duty, or an event), attributes (specific characteristics of entities), and relationships (links amongst entities).
- Relationships include one-to-one, one-to-many, and many-to-many types, with relationships diagrammed with different shapes and lines to represent each relationship type
Other Tools Supporting Analysis: Data Dictionary
- Provides detailed definitions for all terms and data elements related to a system; this is an extremely important document.
Other Tools Supporting Analysis: Process Specification
- This is a description of the process (or procedures) of the system, useful during system analysis.
Participants In System Development
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Users (individuals or groups who use the system)
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Operational users: perform day-to-day tasks.
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Supervisory users: manage operational users.
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Executive users: have global organizational responsibility.
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Management (those who make decisions)
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Auditors (make sure systems are correctly used)
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Systems Analysts (design systems)
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Systems Designers (translate user specifications to technical requirements)
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Programmers (convert designs into actual programs)
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Operations personnel (maintain and run the system)
Information Systems' View-Points/Requirements
- User perspective (data access, requirements, ease to use)
- Technical perspective (volume of data, accuracy, complexity)
- Management perspective (costs, risk, efficiency)
Investigating Methods
- Survey methods (interviews, questionnaires, observations)
- Interview tip: contact interviewee in advance, to allow both parties to agree on the purpose, time, and expectations for the interaction.
- Observation methods (official and unofficial)
- Questionnaire method: gathering information through structured questions.
System Descriptions
- Graphical representation of system process is better than a description in words because it's easier to illustrate processes, activities, and flows in a diagram.
Popular Methods of System Analysis
- Techniques such as structured English, decision tables, data flow diagrams, flowcharts, and decision trees.
Two models of structural system analysis
- Waterfall model: a sequential method with distinct phases
- Spiral model: an iterative approach with repeating phases based on user feedback
Summary of Deliverables/Outputs/Products of SDLC Phases
- This is a table summarizing the products of each phase of an SDLC
Alternative Approaches to Systems Development
- Prototyping: building a scaled-down working version of the system for user feedback
- CASE Tools: computer-aided software engineering tools to automate processes, increasing productivity and improving quality.
- Joint Application Design (JAD): users, managers, and systems analysts collaborate in meetings to gather and specify requirements.
- Rapid Application Development (RAD): rapidly developing a system with user feedback and iterative cycles.
- Participatory Design (PD): emphasizing user involvement in the design and process of how the system operates.
The Sources of Software
- This section explains where software comes from.
- Examples include outsourcing firms, companies that create packaged software or off-the-shelf systems, vendors of enterprise solutions, cloud computing software, open-source software, and companies doing in-house programming.
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