Editing Software design (section)

== Design considerations ==

There are many aspects to consider in the design of a piece of software. The importance of each consideration should reflect the goals and expectations that the software is being created to meet. Some of these aspects are:

* Compatibility - The software is able to operate with other products that are designed for interoperability with another product.  For example, a piece of software may be backward-compatible with an older version of itself.
* [[Extensibility]] - New capabilities can be added to the software without major changes to the underlying architecture.
* [[Modularity]] - the resulting software comprises well defined, independent components which leads to better maintainability. The components could be then implemented and tested in isolation before being integrated to form a desired software system. This allows division of work in a software development project.
* [[Fault-tolerance]] - The software is resistant to and able to recover from component failure.
* [[Maintainability]] - A measure of how easily bug fixes or functional modifications can be accomplished. High maintainability can be the product of modularity and extensibility.
* Reliability ([[Software durability]]) - The software is able to perform a required function under stated conditions for a specified period of time.
* [[Reusability]] - The ability to use some or all of the aspects of the preexisting software in other projects with little to no modification.
* [[Fault-tolerant system|Robustness]] - The software is able to operate under stress or tolerate unpredictable or invalid input.  For example, it can be designed with resilience to low memory conditions.
* [[Computer security|Security]] - The software is able to withstand and resist hostile acts and influences.
* [[Usability]] - The software [[user interface]] must be usable for its target user/audience. Default values for the parameters must be chosen so that they are a good choice for the majority of the users.<ref>{{cite book|editor-last=Carroll|editor-first=John|title=Scenario-Based Design: Envisioning Work and Technology in System Development|year=1995|publisher=John Wiley & Sons|location=New York|isbn=0471076597}}</ref>
* [[Computer performance|Performance]] - The software performs its tasks within a time-frame that is acceptable for the user, and does not require too much memory.
* [[Software portability|Portability]] - The software should be usable across a number of different conditions and environments.
* [[Scalability]] - The software adapts well to increasing data or added features or number of users. According to Marc Brooker: "a system is scalable in the range where [[marginal cost]] of additional workload is nearly constant." [[Serverless computing|Serverless]] technologies fit this definition but you need to consider total cost of ownership not just the infra cost.<ref>{{Cite book |title=Building Serverless Applications on Knative |publisher=O'Reilly Media |isbn=9781098142049}}</ref>