-A black diamond: milestones or significant events on a project with zero duration
-Thick black bars: summary tasks
-Lighter horizontal bars: tasks
-Arrows: dependencies between tasks

Producing a Gantt chart
All scheduling information is graphically represented in a Gantt chart:

-tasks (with name)
-task durations
-relation of task dates to calendar time
-relation of task dates to each other

Constructing a Gantt chart
Draw two axes:

- x-axis: time (days/weeks/months, etc.)
- y-axis: tasks

Label the axes appropriately with calendar dates (x-axis) and task names or WBS numbers (y-axis)
For all tasks:

-draw a horizontal bar, representing the task, at the appropriate (x,y) position (i.e. at
calendar start date in the task’s row)
-make the bar as long as the task’s duration (according to the time axis)
-proceed from the earliest to the latest task

Benefits of Gantt Charts
The Gantt chart is the project manager’s most important tool:

- it provides an overview of the whole project
- the schedule of all tasks can be easily seen
- task relationships/overlaps can be easily seen
- progress can be tracked easily

- Simplest form of schedule to read and interpret

- Easy to create

- Readily communicates results of a network diagram

- Repetitious schedules in bar chart format require far less maintenance than CPM schedules

Disadvantages of Gantt Chart

•Cannot depict intricacies of multiple activity interaction (relationships not shown)
•Simplicity reduces effectiveness and accuracy on large projects with many tasks
•Accuracy is limited because task interdependencies are not tracked
•Too easy to create, thus can produce unrealistic schedules
•Too easy to start from end date, and spread out bars to fit time allotted with
unrealistic sequences, constraints, and durations
•Scheduler’s design logic (relationships) is not readily apparent, thus tracking change impact is difficult

1. Requirements Specification:

The system’s services, constraints and goals are established by consultation with system users. They are then defined in a manner that is understandable by both users and development staff.
This phase can be divided into:

•Requirements capture
•Requirements analysis
•Requirements specification
•Requirements Validation
•Requirements Management

2. System and Software Design:
System design: Partition the requirements to hardware or software systems. Establishes an
overall system architecture

Software design: Represent the software system functions in a form that can be transformed
into one or more executable programs

3. Implementation and Unit Testing:
The software design is realized as a set of programs or program units. (Written specifically, acquired from elsewhere, or modified.)
Individual components are tested against specifications.

4. Integration and System Testing:
The individual program units are:

• integrated and tested as a complete system
• tested against the requirements as specified
• delivered to the client

5. Operation and Maintenance:

Operation: The system is put into practical use.
Maintenance: Errors and problems are identified and fixed.
Evolution: The system evolves over time as requirements change, to add new functions or
adapt the technical environment.

Phase out: The system is withdrawn from service.

Waterfall model strengths and weaknesses:

Strengths

-Emphasizes completion of one phase before moving on
-Emphasizes early planning, customer input, and design
-Emphasizes testing as an integral part of the life cycle

Weaknesses

-Depends on capturing and freezing requirements early in the life cycle
-Each stage in the process reveals new understanding of the previous stages, that
requires the earlier stages to be revised
-Freezing requirements before development starts is unrealistic in innovative projects

CM provides techniques, methods and procedures to maintain product history, to uniquely identified and locate each version of a product and to initiate, evaluate and control change to the product during development and after release.

Goals of Configuration Management:
To ensure the integrity of a product and to make its evolution more manageable.
As CM involved overhead, but when CM is not used there may rise problems and inefficiencies.
Overhead relates to time, resources and effect on software life cycle.

When to Use: Activity Diagrams

Activity diagrams should be used in conjunction with other modeling techniques such as interaction diagrams and state diagrams. The main reason to use activity diagrams is to model the workflow behind the system being designed. Activity Diagrams are also useful for: analyzing a use case by describing what actions need to take place and when they should occur; describing a complicated sequential algorithm; and modeling applications with parallel processes.

However, activity diagrams should not take the place of interaction diagrams and state diagrams. Activity diagrams do not give detail about how objects behave or how objects collaborate.

How to Draw: Activity Diagrams

Activity diagrams show the flow of activities through the system. Diagrams are read from top to bottom and have branches and forks to describe conditions and parallel activities. A fork is used when multiple activities are occurring at the same time. The diagram below shows a fork after activity1. This indicates that both activity2 and activity3 are occurring at the same time. After activity2 there is a branch. The branch describes what activities will take place based on a set of conditions. All branches at some point are followed by a merge to indicate the end of the conditional behavior started by that branch. After the merge all of the parallel activities must be combined by a join before transitioning into the final activity state.

Below is a possible activity diagram for processing an order. The diagram shows the flow of actions in the system’s workflow. Once the order is received the activities split into two parallel sets of activities. One side fills and sends the order while the other handles the billing. On the Fill Order side, the method of delivery is decided conditionally. Depending on the condition either the Overnight Delivery activity or the Regular Delivery activity is performed. Finally the parallel activities combine to close the order.