Software design is the process of creating a software project (SW). The design goal implies the determination of the internal properties of the system and the detailing of its external (visible) properties in accordance with the requirements for the software issued by the customer (the initial conditions of the task), which, in turn, are analyzed.
The course of the software design process and its results will depend not only on the composition of the requirements, but also on the experience of the designer (developer) and on the chosen model of the design process.
After determining the requirements for the software, the developer will receive an agreed clear action plan, a schedule of terms and payments. At the same time, the developer can reduce the development time and improve its quality, and also allows for any other development nuances, for example, legal ones (transfer of copyright to the designed software).
When designing software in advance, the developer has the opportunity to:
- evaluate the development time and cost of the software product;
- eliminate the loss of material costs and time for forced revisions, unnecessary actions, long-term coordination;
- avoid dissatisfaction and disagreements between the customer and the contractor.
The order of software development may differ depending on the specifics of the project, but in general it consists of the following steps:
- Preparations.
- Designing.
- Creation, including design, coding, testing, documentation.
- Support, including implementation and maintenance.
In the process of preparing for the design, organizational issues should be resolved:
- It is necessary to determine the scope of work, and for this you need to find out what the customer can provide (terms of reference, design, layouts), whether the source codes are sufficient and to what extent, what stages they cover.
- Decide on the budget and timing: based on the available materials, they approve the approximate cost, the total duration of the entire project, as well as the duration and exact cost of the next stage.
After solving organizational issues, they sign a contract, receive an advance payment and the materials necessary for work.
Stages and results of design
Designing consists of the following stages:
- Descriptions. This stage includes the joint work of the customer (determines the benefits of the product, requirements for appearance and performance) and the developer (offers algorithmic and technical solutions to the problem).
- Architecture definitions. At this stage, the programming language, database, frameworks and servers are approved.
- Development of terms of reference (TOR). The TOR is drawn up by the architect in accordance with the description and answers to the customer's questions. Then the TOR is agreed with the project manager, then transferred to the client and edits are made.
- The stage of developing layouts, which are then added to the TOR. At this stage, layouts of device circuit diagrams, interfaces, database structure diagrams, and component interaction diagrams are developed.
- Control. During this stage, the architect eliminates the comments of the project manager.
- Statements. At this stage, the customer checks and changes the TOR on his own, or the list of edits is reported to the project manager. After the comments are eliminated, the TOR is approved and attached to the contract.
As a result of the design, a technical task is obtained with an unambiguous and understandable for both the customer and the performer (the project manager, programmers, testers, designers and other participants in the development process can act as the performer) illustration of the answers to the questions:
- What to do (contains a description of the product, functionality, category of users)?
- How to do (contains a description of the architecture)?
- How to check whether the goal has been achieved (test options, evaluation criteria)?
The terms and, accordingly, the cost of the project will depend on its complexity, the more difficult, the longer and more expensive the preparation for it. The development time for small projects takes from a week to a month.
