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To do that we'll have to go back in time to

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the late 60s. So what was happening in the 60s? Well for

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example the first man landed on the moon. That was also

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time when Woodstock took place and also the time when the first

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60 second picture from Polaroid was created. Concurrently to these events,

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which you probably didn't witness in first person, that was also the

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time when people started to realize that they were not able

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to build the software they needed. This happened for several reasons and

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resulted in what we call the software crisis. So let's

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look at some of the most important reasons behind this

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crisis. The first cause was the rising demand for software.

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Now you're used to see software everywhere: in your phone,

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in your car, even your washing machine. Before the 60s,

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however, the size and complexity of software was very limited

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and hardware components were really dominating the scene. Then things

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started to change and software started to be increasingly prevalent.

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So we move from a situation where everything was mostly

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hardware to a situation in which software became more and more

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important. To give an example, I'm going to show you the growth

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in the software demand at NASA along those years. And in

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particular, from the 1950s to more or less 2000. And this

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is just a qualitative plot but that's more or less the

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ways things went. So the demand for software in NASA grow

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exponentially. And the same happened in a lot of other companies.

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For example, just to cite one, for Boeing. So the

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amount of software on airplanes became larger and larger. The

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second cause for the software crisis was the increasing amount

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of development effort needed due to the increase of product complexity.

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Unfortunately, software complexity does not increase linearly with size. It

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is not the same thing to write software for a

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class exercise or a small project, or a temp project,

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than it is to build a software for a word processor,

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an operating system, a distributed system, or even more complex and larger

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system. And what I'm giving here is just an indicative size for

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the software so the class exercise might be 100 lines of code,

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the small project might be 1000 lines of code, in the other thousand

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lines of code, and so on and so forth. For the former,

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the heroic effort of an individual developer can get the job done.

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So that's what we call a programming effort. If you're a good

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programmer, you can go sit down and do it, right. For the latter,

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this is not possible. This is what we called the

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software engineering effort. In fact, no matter how much programming languages,

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development environments, and software tools improve, developers could not keep

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up with increasing software size and complexity. Which leads us to

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the third problem that I want to mention and the

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third reason for the software crisis. And this cause is the

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slow developer's productivity growth. So let me show this again

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with a qualitative diagram. And this is taken from the IEEE

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Software Magazine. And what I'm showing here is the growth in

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software size and complexity over time, and how the developers' productivity

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really couldn't keep up with this additional software complexity, which resulted

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in this gap between what was needed and what was actually available.