Scalar means to climb. So scalability, in this context, is the ability to increase the size of the software or its use.
When we talk about the scalability of software itself we’re talking about having a code and an architecture that’s easy to maintain, to increase its functionality, to have multiple people work on it.
Eventually we can use the term to indicate that the software can be used by a large number of users (customers). In the sense of persons or enterprises.
The scalability of use has to do with the ability to increase memory consumption, process, meet high demand processing demands and possibly access competition.
There are numerous techniques to enable better software scalability.
Some software works very well with low amount of data or access, but when this increases, it has problems. No use for more and better equipment. It would be a palliative solution.
Some things grow linearly and this is good, scale well. Problems occur when software grows and needs grow exponentially. That is, the increased need generates a proportionally larger capacity increase. It is a geometric progression.
Of course, the ideal would be to have a logarithmic progression, so each increase in need requires an increase in capacity in a much smaller proportion. But it is rare to achieve this in all software, except in one-off things of software.
Read more about this at Big-O (in English much better).
Probably the term is used in more software contexts.
We often use the term referring to the solution as a whole and not just to the software. Scalability has to do with the ability to meet the need well by adding infrastructure. There are cases where the software is not prepared for this. Adding infra will bring other problems that the software does not know how to handle. Scalable software adapts to this.
Scalable software is more vulnerable to attack.
Wikipedia article. In English much better.
For this question, there is nothing else that needs to be improved. I have accepted the answer.
– Duds