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Simula: The World‘s First Object-Oriented Programming Language

Simula is considered the first object-oriented programming (OOP) language, created in the 1960s by Norwegian computer scientists Ole-Johan Dahl and Kristen Nygaard. While not widely used today, Simula introduced fundamental concepts that influenced nearly every modern OOP language that followed.

In this comprehensive guide, we‘ll cover:

  • The origins of Simula and what inspired its creation
  • Key concepts introduced like objects, classes, inheritance
  • What you can do with Simula and types of programs it suits
  • How Simula compares to related languages like Smalltalk
  • Pros and cons of using this language
  • Simula‘s legacy and influence on languages like C++ and Java

So let‘s begin at the beginning, with a Norwegian computer center and an idea to model the world through code…

History and Origins of Simula

Simula has its roots at the Norwegian Computing Center (NCC) in Oslo during the early 1960s. At the time, a mathematician named Kristen Nygaard became interested in using code to simulate complex, real-world systems.

However, Nygaard lacked specialized programming skills. So he recruited Ole-Johan Dahl, one of Norway‘s leading computer scientists, to help bring his vision to reality.

By 1962, Nygaard and Dahl outlined the key concepts for what they called a "simulation language." They dubbed their new programming language "Simula I"…

Key Concepts Introduced in Simula

At its core, Simula introduced a major paradigm shift in programming languages – modeling everything as "objects" rather than linear functions or procedures. These objects could pass messages back and forth, allowing complex simulations never before possible in code.

More specifically, Simula introduced classes, subclasses, objects, virtual procedures, inheritance, and discrete event simulation capabilities. These basic building blocks are still essential to OOP languages today like Java or C++.

For example, let‘s quickly illustrate the concept of "objects" in Simula:

CarObject = NEW Car;  //Create a car object from Car class 
CarObject.TurnOnRadio; //Call method of car object

So already by the mid-1960s, you had this whole new programming model focused around objects that interact almost like real-world entities. This was a huge leap from procedural languages of the time…

What You Can Do With Simula

As the name implies, Simula aimed primarily at simulations modeling real-world systems from a user‘s point of view. For example:

  • Simulating complex computing/engineering systems
  • Business process workflows and organizational models
  • Communication protocols like TCP/IP networks
  • Graphical rendering and computer animation
  • Educational programs with interactive lessons

These were now possible to tackle with a degree of realism never before seen, all thanks to modeling components as intelligent "objects" rather than step-by-step procedures.

Over time, developers would use Simula for everything from VLSI design to algorithms, process modeling, typesetting, and even computer games.

How Simula Compares to Smalltalk

Another well-known early object-oriented language was Smalltalk, first released in 1972.

While Smalltalk took the concepts in Simula even further, there were still some key differences:

  • Data structures – Simula based its objects on ALGOL 60 activation records while Smalltalk introduced a more flexible, uniform data structure.

  • Code execution – Smalltalk was one of the first "dynamic" execution models whereas Simula used a more static, compilation approach.

  • Application domains – Simula targeted large-scale simulations while Smalltalk aimed more at general rapid application development.

So in some ways, Smalltalk built and expanded on the fundamental building blocks introduced by Simula for modeling complex systems with object-oriented code…

Pros and Cons of Using Simula

Advantages of Simula:

  • Allows robust modeling of complex, real-world systems
  • Introduction of key OOP concepts like inheritance
  • Framework for many later languages like Java/C++
  • Automatic memory management

Disadvantages of Simula:

  • Complex syntax had a steep learning curve
  • Not as computationally efficient or expressive as later languages
  • Lacked certain features like multithreading

So while pioneering, Simula did have some limitations that its successors improved upon over time. But none of these later languages would have been possible without Simula‘s innovations…

Simula‘s Lasting Legacy and Influence

Although Simula never saw widespread adoption, its fundamental concepts deeply influenced generations of future software engineers.

Object-oriented methodology used everywhere today in languages like C++, Java, C# traces its lineage directly back to Simula in the mid-1960s. Entire paradigms for modeling complex domains were forever changed.

As processing power caught up with the resource demands of OOP techniques, adoption exploded in the 1980s/1990s. Soon even procedural languages like C adopted OOP modules and extensions.

So while no longer used much in practice, Simula opened the door for object-oriented abstractions taken for granted now across nearly all modern programming languages and platforms.

Conclusion

In the end, Simula pioneered almost all the basic object-oriented concepts still essential five decades later – dynamic binding, inheritance, classes/objects, etc.

Without visionaries like Nygaard and Dahl modeling the world through coded "objects" for the first time, we may still be using purely procedural languages today. And much of the software-driven innovation powering our modern world could look very different.

So while it didn‘t transform software development overnight in the 1960s itself, Simula planted the seeds for one of the biggest programming revolutions still playing itself out 50 years later!