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Why a software factory is the wrong metaphor

A metaphor that is used a lot to describe the software development process is that of a software factory. Wikipedia describes the concept of a software factory as follows:

A software factory is a structured collection of related software assets that aids in producing computer software applications or software components according to specific, externally defined end-user requirements through an assembly process. A software factory applies manufacturing techniques and principles to software development to mimic the benefits of traditional manufacturing.

This brings the following image on my mind:

 


On one end we put requirements in and on the other end working software comes out. This feeds the idea that software development is a manufacturing activity where human intervention could be minimized and most of the work can be automated. 

But this idea is not correct; as Jack Reeves says in his essay What Is Software Design? coding is in fact an act of design not manufacturing. What can be seen as manufacturing in software development is compilation, something that we already have automated and is done by machines for us.  

Coding is an act of design not manufacturing.

So if we look at industrializing the software development process, what can be automated are things like testing, compiling, deployment but not the coding itself.

Here is an excerpt from Jack’s essay:

“The final goal of any engineering activity is some type of documentation. When a design effort is complete, the design documentation is turned over to the manufacturing team. This is a completely different group with completely different skills from the design team. If the design documents truly represent a complete design, the manufacturing team can proceed to build the product. In fact, they can proceed to build lots of the product, all without any further intervention of the designers. After reviewing the software development life cycle as I understood it, I concluded that the only software documentation that actually seems to satisfy the criteria of an engineering design is the source code listings.”

“Designing software is an exercise in managing complexity. The complexity exists within the software design itself, within the software organization of the company, and within the industry as a whole. Software design is very similar to systems design. It can span multiple technologies and often involves multiple sub-disciplines. Software specifications tend to be fluid, and change rapidly and often, usually while the design process is still going on. Software development teams also tend to be fluid, likewise often changing in the middle of the design process. In many ways, software bears more resemblance to complex social or organic systems than to hardware. All of this makes software design a difficult and error prone process. None of this is original thinking, but almost 30 years after the software engineering revolution began, software development is still seen as an undisciplined art compared to other engineering professions.”

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