All of those languages listed above produce what is know as Legacy Code in the Information Technology Industry.
So, what is Legacy Code?
Simply put, Legacy Code is a programming language or framework which although may be a few years old now is still being used commercially.
Some examples of Microsoft Legacy Languages / Frameworks are:
Active Server Pages programmed in VBScript
Visual Basic 6
Visual Basic .NET
Earlier versions of SQL Server
In an ideal world there would be no such thing as Legacy Code and all exsiting applications written in these old languages would be upgraded to leverage the latest technologies.
Unfortunately the cost and risks in migrating existing applications to the latest technology can be overwhelming and businesses have no other option but to keep using their existing legacy application.
Further compounding the problem is the fact that it can be extremely hard to find developers who have the knowledge needed to maintain these legacy applications as most developers move ahead with the times.
A solid commercial working knowledge of these old frameworks and languages is a must. Therefore you need developers who have been developing as long as these languages have been commercially available; In some cases that’s almost twenty years