Data System
A computer program, or computer system, is a tool, like a hammer or a fork, that is meant to manipulate data. It also needs to be manufactured with the end goal in mind (after all the data is collected and combined, what is the expected results?)
Analysing the manufacturing of a hammer one could ask: for which types of nails this tool will be able to handle? How big it needs to be? Who will be using it, someone trying DIY at home or a professional carpenter?
Questions like these will help preventing rework if something goes wrong during the fabrication of this hammer.
That is the reason for a Data Systems Analyst to design a model of a system before writing it, to illustrate how it will look like and what it will do, avoiding mistakes and misinterpretation of specification and documents. Like an architect does with the property plans! To construct a system you need to know what it is supposed to do before you start making one to avoid rework.
