We've got a secret to share with you: science and engineering discoveries don't just happen without rhyme or reason.

Except maybe the goldfish walker. There's no point to that one.

What's that? What's our point? Before computers could be invented, people had to think about what a computer would do and why they'd need it. Even before the 1910s, classic writers like Jonathan Swift and E.M. Forster thought about machines that could create information to simulate intelligence and real life.

Maybe they didn't get everything right, but the key thing is that they were thinking about things like the internet and instant messaging. It just took science and technology a while to catch up with them.

Although the specific hardware and software may be different and designed specifically to do one thing or another, all computers share the same, fundamental concepts. And we aren't even talking about the man vs. machine trope in all the best science fiction films.

That being said, you can group computers into different types based on what people use them for. They aren't all the same and you should know the differences.

Mainframe Computers

Mainframe computers were the first major, commercialized computers from back in the 50s.

These guys took up entire rooms, letting you access their computing power from workstation monitors known as dumb terminals. Those dumb terminals didn't have any of their own processing power; they had to ask the mainframe computer to do any- and everything.

Mainframe computers can have multiple processors with different operating systems and allow many programs to run at the same time. Today you'll be able to find mainframe computers at businesses that deal with giant amounts of data (think corporate payroll processing, state and federal tax returns, and healthcare claims).

But more importantly: you can also find them peppered in Hollywood pseudo-jargon.

Supercomputers

Just like the mainframe, supercomputers are huge (hence the name). Unlike mainframes, people typically only use them for one, complex task. All of the computer’s resources are thrown at that one task to help find a solution. To deserve all that work, that task is usually a big one: something researchers are using to simulate and model some big, hairy problem. Problems like these usually take multiple years to solve. We're talking about things like simulating flight and processing climate patterns.

Say we're talking about monitoring climate change with supercomputers. If scientists can crunch giant data sets to figure out what kind of severe weather can be predicted when, we stand a much better chance at being able to react to and protect against those giant storms.

Supercomputers are fabulous at helping researchers solve these kinds of problems.

Personal Computers (PCs)

As computing technology improved in the 60s, there was less of a need to make people share mainframe computers all the time, giving rise to the—wait for it—personal computer. The first PC (Programma 101) was developed in the 1960s by an Italian company called Olivetti. NASA bought several of these early devices and used them to support the 1969 Apollo moon landing. It wasn‘t until the early 1980s (twenty years after NASA used those Programmas to send astronauts to the moon) that PCs became accessible to families and business employees.

The first widely available PCs sold for about $3,000. By 2010 the average sale price had come down to about $550.

Sound like a crazy decrease? It is. It's a giant decrease.

PCs are all about giving you every function you'd need in your day-to-day life. Instead of focusing on one, complex task, they can handle hundreds of simultaneous tasks so that you can get all your work done. Even if that work's actually just playing the latest video game.

Laptops

Functionally, a laptop is basically the same as a personal computer (plus maybe some added risks). The main difference is that you can move a laptop much more easily than whatever tower, monitor, speaker, and webcam setup you might have at home.

That isn't to say laptops are automatically better than PCs. Because laptops have to fit in backpacks and manila envelopes, their components end up more squished together. That lack of space makes changes like hard disk and memory upgrades more difficult.

Plus, it's virtually impossible to make those changes without paying someone else to do it.

Tablets

Boy, if you thought laptops had cramped quarters, tablets are even smaller. They even replace the mouse and keyboard with a touchscreen display. Even though they've also been around since the 80s, tablets didn't really become popular until smartphones started gaining momentum. (Source)

Computer Networks

When you link a group of computers together to share data or resources—whether they're PCs, laptops, or supercomputers—you're making a computer network. Even if you're just sharing a printer with your roommate, technically you're on a computer network.

The most common type of networks (aside from the deal your brokered with your roommate that they'd share the printer if you let them control the remote) are:

• Local Area Networks (LANs): computers all at the same site, all connected to a common file server. 
• Wide Area Networks (WANs): computers located at different sites—anywhere in the world—with a common file server.

Generally, if you've got four users or more involved, it makes more sense money-wise to have those users work on a network so that they can share devices and software. That way, you won't have to duplicate devices and software to every user.

These kinds of systems have pros and cons. (Don't they always, though?)

Pros:

• When you can share software between multiple users, the costs per user go way down. 
• Software upgrades only need to be installed in one location, making them much easier to manage.

Cons:

• Whenever you have a network, you need an admin to take care of the network's set-up and maintenance. That person also needs to make sure everything's safe and secure from hackers. 
• If a shared device breaks, what could have been a problem for one person becomes a problem for everyone. Not so fun.

Robots

Robots aren't all computer. We aren't talking about the ghost in the machine here, we're just saying that there are so many other mechanical and electrical components to robots that make them do more than sit there and crunch numbers.

Still, the computer programming part tells the robot what to do and how to do it. You could think of the computer as the brains of the operation, really. A robot that can travel across the surface of Mars looking for signs of life (preferably in mom form) with all the mechanical construction and battery power to make it move, but it won't budge an inch if it doesn't have software that tells it where to go.

Robots are a great option for jobs that are dirty, dangerous, or dull. They can help combat fires, disarm bombs, navigate areas with land mines, and balance really well. All controlled by computers.