(a) During systems development life cycle (SDLC): the systems analyst uses some tools to model the users requirements in such a way that he is able to communicate his understanding of the users needs.
Identify and describe three tools the systems analyst may use. to model the systems requirements.
(b) (i) Graphical user interface (GUI) ,have proved to be more user friendly than current character based systems.
Other than the graphical user interface, give a summary of at least three interfaces you would use in “the design of systems.
(ii) Briefly explain three ways in which GUI makes a system user friendly.
(c) Using your own experience, explain why more-and more software is being purchased for windows environment as opposed to character based environment.
a) System analyst
This is a specialist who translates business problems and requirements into information requirements and systems, acting as liaisons between the information systems department and the rest of the organization.
System development life cycle
This is a traditional methodology for developing an information system that partitions the systems development process into formal stages that must be completed sequentially with a very formal division of labour between the end users and the information systems specialists.
Tools that may be used the analyst to model the systems requirements:
1. Data flow diagrams (DFDs)
These are visual tools that show the various processing steps and data flow through a system. DFDs are constructed using four major components:
o External entities
These are sources of data input to the system or the destinations of data from the system. The standard notation for an external entity is a square.
o Data stores
They represent the stores of data within the system. Examples are computer files or databases.
These are events that change the state of data fed to them. The standard notation for a process is a circle.
o Data flows
They are movements of data from one component to the other. The standard notation for a data flow is a unidirectional, labeled arrow
2. System flowcharts
These are diagrammatic representations that illustrate the sequence of operations performed to get the solution to a problem. They are useful in understanding the logic of complicated and length problems.
3. Entity relationship models (ERMs)
They are detailed logical representations of the data for an organization or for a business area. They are expressed in terms of the entities in the business area, the relationships among the entities and the attributes of the entities and their relationships. An entity is an object of interest (i.e. a thing or concept) about which data is to be stored. An attribute is a property or characteristic of an entity.
4. Entity life history diagrams (ELHs)
These are diagrammatic representations of the lives of entities from their creation to deletion. The life of an entity is expressed as the permitted sequence of events that can cause an entity to change. An event may be thought of as whatever brings a process into action to change entities.
5. Data dictionary
This is a central storehouse of data about an information systems data and data transformations. Data dictionaries are necessary because it is impossible to fully describe all components of DFDs and E-R models. Data dictionaries describe in detail data flows, data stores, external entities, data structures, system processes and data elements.
b) (i) Graphical User Interface (GUI)
This refers to a human computer interface (HCI) based upon a graphical display. A GUI makes use of icons, buttons, bars and boxes to perform tasks.
Human Computer Interface (HCI)
This refers to the environment where the interaction between end users and the computer is said to take place.
Other interfaces that could be used in the design of systems:
1. Command driven interfaces- these enable the user to quickly and simply instruct the computer on what to do via commands.
2. Menu driven interfaces- these provide users with menus. The menus provide the user with a number of options and a simple means of selecting between them.
3. Direct manipulation interfaces- these present the user with a set of options that are represented icons. The user moves the cursor using the mouse until it is over the icon and then clicks the mouse button to select the option.
4. User Interface Management System (UIMS)- These create a means which a consistent interface with the same ―look and feel‖ can be provided for any number of different applications within the same system.
(ii) Ways in which a GUI makes a system user friendly:
1. GUIs minimize the time taken to perform trivial operations e.g. opening a file. Forinstance, to open a file in the GUI environment of the windows range of operating systems one only has to double-click on the icon (graphical symbol) representing the program.
2. One doesn‟t have to memorize commands with a GUI as compared to a command-driven interface. Hence, GUIs make it very easy to learn how to use a system.
3. GUIs minimize the typing of data required from the user because they provide agraphical means to supplement typing of data. Hence, they are convenient to system users.
4. It‟s easy to access help form a GUI as compared to other interfaces such as command-driven interfaces. To access help, for instance, in a windows operating system environment, one only has to locate and click-on the help option in the menu bar of the program‘s window. For a command-driven interfaces such as that of Microsoft DOS(disk operating system), one has to recall the help command before he/she can access help. If the user has no clue of the help command, then he/she is stuck.
c) Reasons why more and more software is being purchased for windows environment as opposed to character-based environment.
1. The windows environment saves on training of users. Most software developed for the windows environment conforms to some basic standards. For instance, there are always three buttons to the top right end of each window for the purposes of minimizing, closing or maximizing the window. Usually, also, there is always a menu-bar present in all program windows to provide users with various options. Since most software applications adhere to these standards, users of windows environment software can easily learn how to use many more software after learning how to use one software. Command/character-based systems have minimal standards. For instance, there are no conventions as to the naming of commands. This makes it very difficult to learn many different programs produced for character-based environments.
2. Majority of the software today is based on a windows environment because its user friendly. Hence, customers have a wide variety to choose from.
3. Since majority of the software available is for the windows environment, organizations continue to purchase more and more windows-based software as compared to character- based software in order to ensure compatibility with already existing systems.