Cover the basics and learn how to design and develop distributed systems.

Become a Distributed Systems Professional

Gone are the days when monolithic applications were the norm. Most applications we use today are too complex for that type of construction. Instead, most applications that appear as a single unit are actually built as a collection of inter-operating but independent computational components. Developers are expected to have mastery over a programming language or two. Moreover, they should also know the basics of distributed systems.

In this module, we’ll learn what distributed systems are, and learn about the challenges unique to distributed systems. We’ll cover popular architectural patterns for achieving targets like replication and sharding. We’ll complete the module with a study of two popular distributed systems: Apache Spark and Apache Druid. With the knowledge gained through this module, we’ll be able to design and develop distributed systems. We’ll also develop an understanding of optimal design and architectural choices based on the application requirements.

Introduction to Distributed Systems for Dummies

## What is a distributed system--take 1

That's easy to answer.

> A distributed system is a system that is distributed. 

Simple!

But we should really avoid defining a term using the term itself.

Let's try again.

## What is a distributed system--take 2

You are likely familiar with the term ‘system’. Think of your laptop. That’s a system containing CPUs, RAMs, disk drives, numerous chips, etc.

In this context, a computer is a system, a system that is capable of storing information and also crunching numbers.

On the other hand, “distributed” means scattered, divided, or dispersed .

So when you hear the term “distributed systems”, you can safely assume that the term involves multiple machines, possibly hundreds or thousands of them.

But hang on, this is still not a definition. Let's try this one more time.

## What is a distributed system--take 3

This time, let’s first think of a system that isn’t distributed.

A single system is not a distributed system. Your single machine operating solely on its own is not a distributed system.

But hang on, don’t forget that your machine has multiple cores. All those cores may run distinct programs in parallel.

And those programs are perhaps communicating with one another. Does that mean all those cores of your machine create a distributed system?

Well, technically, yes. But this is not valid in the context of today’s reality. Rather, multiple machines have to be used for a system to be called ‘distributed’.

>Before giving more of a formal definition, there is a distributed system that exists everywhere around you, and which you definitely use every day. This is so obvious that you might actually never notice it. Can you think of what it could be? We will discuss the answer in the following lesson.

Now let's go for a formal definition:

> A **distributed system** is a collection of autonomous computing elements
that appears to its users as a single coherent system. 
> <div align = "right""> <em>Distributed Systems</em>, Steen & Tanenbum </div>

There are two very important aspects to this definition. Let's discuss them.


# What is a distributed system--take 1

That's easy to answer.

> A distributed system is a system that is distributed. 

Simple!

But we should really avoid defining a term using the term itself.

Let's try again.

# What is a distributed system--take 2

You are likely familiar with the term ‘system’. Think of your laptop. That’s a system containing CPUs, RAMs, disk drives, numerous chips, etc.

In this context, a computer is a system, a system that is capable of storing information and also crunching numbers.

On the other hand, “distributed” means scattered, divided, or dispersed .

So when you hear the term “distributed systems”, you can safely assume that the term involves multiple machines, possibly hundreds or thousands of them.

But hang on, this is still not a definition. Let's try this one more time.

# What is a distributed system--take 3

This time, let’s first think of a system that isn’t distributed.

A single system is not a distributed system. Your single machine operating solely on its own is not a distributed system.

But hang on, don’t forget that your machine has multiple cores. All those cores may run distinct programs in parallel.

And those programs are perhaps communicating with one another. Does that mean all those cores of your machine create a distributed system?

Well, technically, yes. But this is not valid in the context of today’s reality. Rather, multiple machines have to be used for a system to be called ‘distributed’.

>Before giving more of a formal definition, there is a distributed system that exists everywhere around you, and which you definitely use every day. This is so obvious that you might actually never notice it. Can you think of what it could be? We will discuss the answer in the following lesson.

Now let's go for a formal definition:

> A **distributed system** is a collection of autonomous computing elements
that appears to its users as a single coherent system. 
> <div align = "right""> <em>Distributed Systems</em>, Steen & Tanenbum </div>

There are two very important aspects to this definition. Let's discuss them.


Learn the definition of a distributed system in depth.

What is a Distributed System?

What is a distributed system–take 1

What is a distributed system–take 2

What is a distributed system–take 3