Move It On Over — Third and Fourth Generation Software: A Primer

While presenting to organizations regarding business intelligence and project management solutions I often find myself explaining the current state of programming and what current technology brings to the table. Among these discussions is the difference between third and fourth generation software, not just from the perspective of programming–or the Wikipedia definition (which is quite good, see the links below)–but from a practical perspective.

Recently I ran into someone who asserted that their third-generation software solution was advantageous over a fourth generation one because it was “purpose built.” My response was that a fourth generation application provides multiple “purpose built” solutions from one common platform in a more agile and customer-responsive environment. For those unfamiliar with the differences, however, this simply sounded like a war of words rather than the substantive debate that it was.

For anyone who has used a software application they are usually not aware of the three basic logical layers that make up the solution. These are the business logic layer, the application layer, and the database structure. The user interface delivers the result of the interaction of these three layers to the user–what is seen on the screen.

Back during the early advent of the widespread use of PCs and distributed computing on centralized systems, a group of powerful languages were produced that allowed the machine operations to be handled by an operating system and for software developers to write code to focus on “purpose built” solutions.

Initially these efforts concentrated on automated highly labor-intensive activities to achieve maximum productivity gains in an organization, and to leverage those existing systems to distribute information that previously would require many hours of manual effort in terms of mathematical and statistical calculation and visualization. The solutions written were based on what were referred to as third generation languages, and they are familiar even to non-technical people: Fortran, Cobol, C+, C++, C#, and Java, among others. These languages are highly structured and require a good bit of expertise to correctly program.

In third generation environments, the coder specifies operations that the software must perform based on data structure, application logic, and pre-coded business logic.These three levels of highly integrated and any change in one of them requires that the programmer trace the impact of that change to ensure that the operations in the other two layers are not affected. Oftentimes, the change has a butterfly effect, requiring detailed adjustments to take into the account the subtleties in processing. It is this highly structured, interdependent, “purpose built” structure that causes unanticipated software bugs to pop up in most applications. It is also the reason why software development and upgrade configuration control is also highly structured and time-consuming–requiring long lead-times to even deliver what most users view as relatively mundane changes and upgrades, like a new chart or graph.

In contrast, fourth generation applications separate the three levels and control the underlying behavior of the operating environment by leveraging a standard framework, such as .NET. The .NET operating environment, for example, controls both a library of interoperability across programming languages (known as a Framework Class Library or FCL), and virtual machine that handles exception handling, memory management, and other common functions (known as Common Language Runtime or CLR).

With the three layers separated, with many of the more mundane background tasks being controlled by the .NET framework, a great deal of freedom is provided to the software developer that provides real benefits to customers and users.

For example, the database layer is freed from specific coding from the application layer, since the operating environment allows libraries of industry standard APIs to be leveraged, making the solution agnostic to data. Furthermore, the business logic/UI layer allows for table-driven and object-oriented configuration that creates a low code environment, which not only allows for rapid roll-out of new features and functionality (since hard-coding across all three layers is eschewed), but also allows for more precise targeting of functionality based on the needs of user groups (or any particular user).

This is what is meant in previous posts by new technology putting the SME back in the driver’s seat, since pre-defined reports and objects (GUIs) at the application layer allow for immediate delivery of functionality. Oftentimes data from disparate data sources can be bound together through simple query languages and SQL, particularly if the application layer table and object functionality is built well enough.

When domain knowledge is incorporated into the business logic layer, the distinction between generic BI and COTS is obliterated. Instead, what we have is a hybrid approach that provides the domain specificity of COTS (‘purpose built”), with the power of BI that reduces the response time between solution design and delivery. More and better data can also be accessed, establishing an environment of discovery-driven management.

Needless to say, properly designed Fourth Generation applications are perfectly suited to rapid application development and deployment approaches such as Agile. They also provide the integration potential, given the agnosticism to data, that Third Generation “purpose built” applications can only achieve through data transfer and reconciliation across separate applications that never truly achieve integration. Instead, Fourth Generation applications can subsume the specific “purpose built” functionality found in stand-alone applications and deliver it via a single platform that provides one source of truth, still allowing for different interpretations of the data through the application of differing analytical approaches.

So move it on over nice (third generation) dog, a big fat (fourth generation) dog is moving in.

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