Please enable JavaScript.

Coggle requires JavaScript to display documents.

CHAPTER 4 SYSTEM DESIGN - Coggle Diagram

- - - - –Often, the user interface mainly consisted of process-control screens that allowed the user to send commands to the system.
        –As information management evolved from centralized data processing to dynamic, enterprise-wide systems, the primary focus also shifted — from the IT department to the users themselves
        
        –User-centered system
        •Requires an understanding of human-computer interaction and user-centered design principles
    - - –Human-computer interaction (HCI) describes the relationship between computers and people who use them to perform their jobs
        –Main objective is to create a user-friendly design that is easy to learn and use
        –IBM believes that the user interface evolution will lead to computers that truly are consumer products that are simple and natural for the general population to use.
    - - i. Understand the Business
        
        •The interface designer must understand the underlying business functions and how the system supports individual, departmental, and enterprise goals.
        •The overall objective is to design an interface that helps users to perform their jobs.
      - ii. Maximize Graphical Effectiveness
        
        •Studies show that people learn better visually.
        •The immense popularity of Apple Mac OS and Microsoft Windows is largely the result of their graphical user interfaces that are easy to learn and use.
      - iii. Think Like a User
        
        •A systems analyst should understand user experience, knowledge, and skill levels.
        •To develop a user-centered interface, the designer must learn to think like a user and see the system through a user’s eyes.
      - iv. Use Models and Prototypes
        
        •From a user’s viewpoint, the interface is the most critical part of the system design because it is where he or she interacts with the system
        •It is essential to construct models and prototypes for user approval.
      - v. Focus on Usability
        
        •The user interface should include all tasks, commands, and communications between users and the information system.
        •Each screen option leads to another screen, with more options.
      - vi. Invite Feedback
        
        •Even after the system is operational, it is important to monitor system usage and solicit user suggestions.
        •You can determine if system features are being used as intended by observing and surveying users.
      - vii. Document Everything
        
        •You should document all screen designs for later use by programmers.
        •If you are using a CASE tool or screen generator, number the screen designs and save them in a hierarchy similar to a menu tree.
  - - - 1)Design a transparent interface
        •Facilitate the system design objectives, rather than calling attention to the interface
      - 2)Create an interface that is easy to learn and use
        •Clearly label all controls, buttons, and icons
        •Select only those images that users can understand easily, and provide on-screen instructions that are logical, concise, and clear
      - 3)Enhance user productivity
        Organize tasks, commands, and functions in groups that resemble actual business operations
      - 4)Make it easy for users to obtain help or correct errors
        •Ensure that Help is always available
        •Provide user-selected Help and context-sensitive Help
      - 5)Minimize input data problems
        •Create input masks
        •Display event-driven messages and reminders
      - 6)Provide feedback to users
        •Display messages at a logical place on the screen, and be consistent
      - 7)Create an attractive layout and design
        •Use appropriate colors to highlight different areas of the screen
        •Use special effects sparingly
      - 8)Use familiar terms and images
        •Remember that users are accustomed to a pattern of red=stop, yellow=caution, and green=go
        •Provide a keystroke alternative for each menu command
  - - - –Menu bar
      - –Toolbar
      - –Command button
      - –Dialog box
      - –Text box
      - –Toggle button
  - - - –List box – scroll bar
      - –Drop-down list box
      - –Option button, or radio button
      - –Check box
      - –Calendar control
      - –Switchboard
- - - - •data entry is performed on a specified time schedule [ daily, weekly, monthly, or longer ]
      - •example: batch input occurs when a payroll department collects time cards at the end of the week and enters the data as a batch
    - - •batch input - used in specific situations
      - •but most business activity requires online data
      - •Source data automation is fast and accurate, and minimizes human involvement in the translation process.
  - - - 1.Sequence check
        –used when the data must be in some predetermined sequence
        –example : if the user must enter work orders in numerical sequence, then an out-of-sequence order number indicates an error
      - 2.Existence check
        –used for mandatory data items
        –example : if an employee record requires a Social Security number, an existence check would not allow the user to save the record until he or she enters a suitable value in the Social Security number field
      - 3.Data type check
        –tests to ensure that a data item fits the required data type
        –example : a numeric field must have only numbers or numeric symbols, and an alphabetic field can contain only the characters A-Z or a-z
      - 4.Range check
        –tests data items to verify that they fall between a specified minimum and maximum value
        –example : daily hours worked by an employee must fall within the range of 0 to 24
      - 5.Reasonableness check
        –identifies values that are questionable, but not necessarily wrong
      - 6.Validity check
        –used for data items that must have certain values
        –example : if an inventory system has 20 valid item classes, then any input item that does not match one of the valid classes will fail the check
      - 7.Combination check
        –performed on 2 or more fields to ensure that they are consistent or reasonable when considered together
      - 8.Batch controls
        –totals used to verify batch input
        –might check data items such as record counts and numeric field totals
  - - - •Email
        –Employees send and receive e-mail on local or wide area networks, including the Internet.
      - •Blogs
        –Web-based logs, called blogs, are another form of Web-based output.
      - •Instant messaging
        –This popular form of communication is another way for individuals and companies to communicate effectively over the Internet.
    - - An incredibly diverse marketplace requires many forms of specialized output and devices such as these:
        –Portable, Web-connected devices that can run applications, handle multimedia output, and provide powerful, multipurpose communication for users
        –Retail point-of-sale terminals that handle computer-based credit card transactions, print receipts, and update inventory records