Determine the Software development models
Software Engineering deals with development of software. Thus, understanding the basic characteristics of software is essential. Software is different from other engineering products in below ways:
1. Engineering products once developed can't be changed. To modifications the product, remanufacturing and redesigning is required. In case of software, eventually changes are to be done in code for any changes to take effect.
2. The Other Engineering products are visible but the software as such is not visible. That's why, it is said that software is developed, but not manufactured.
However like other products, it's first designed, then produced, it can't be manufacturedautomaticallyon an assembly line like other engineering products. Nowadays, CASE (Computer Aided Software Engineering) tools are available for software development. Still it depends on programmer's creativity andskill. Creative skills of the programmer is difficult to quantify and standardise. Thussame software developed by different programmers may take varying amount of resources, time and may have variable cost.
3. Software doesn't fail in traditional sense. Engineering products has wear and tear in the operation. Software can be run any number of times without wear and tear. Software is considered as failed if:
a) It doesn't operate correctly.
b) Doesn't provide required number of features.
4. Engineering products can be perfectly designed however in the case of software, though good the design, it can never be 100%error free. Even best quality software isn't entirely error free. A software is known as good quality software if it performs the required operation, even if it has a few errors.
5. Testing of normal engineering products and software engineering products are on different parameters. In former, it can be full load testing, etc., while in case of software, testing means identification of test cases in that software may fail. Therefore, testing of software means running of software for different inputs. By testing, presence of errors is identified.
6. Unlike most of the other engineering products, software can be reused. Once a piece of code is written for some application, it can be reused.
7. Management of software development projects is a highly demanding task because it involves assessment of the developer's creative skills. Estimation regarding the time and cost of software needs standardisation of developers creativity, which can be a variable quantity. It means that software projects can't be managed such as engineering products. Correction of a bug in the case of software may take hours though it maynotbe the case with normal engineering products.
8. Software isn't vulnerable to external factors such as environmental effects. Though the same external factors may harm hardware. Hardware component maybe replaced with spare parts in the case of failure while the failure of a software component may indicate errors in design.
Thus, characteristics of software are quite different from other engineering products. Therefore, software industry isquitedifferent from other industries.