Lesson 2: A Brief History of Computers
Compared to the history of mankind, computers are a mere infant. However, in the short time that they have existed they have literally transformed our world in nearly every aspect. Not a single field or industry exists on this planet that doesn’t make regular use of computers now. Let’s take a brief look at this history.
What is a Computer?
A computer is a machine designed to compute data. Even though you may not realize it, even the modern computers we have now, at their core, simply do that. They compute data that we, the programmers, give them. Even advanced 3D simulations can be reduced to simple computation.
For a machine to be considered a computer it must have two primary properties: it is programmable and it must be able to perform automated calculations.
Our modern computers easily satisfy this. Their CPU (central processing unit) is the unit that performs the automatic calculations and we can obviously program them with great ease through Javascript, PHP, C++, and so on.
A CPU consists of an ALU (Arithmetic and Logic Unit), a control unit, memory, and input and output devices. Early on these used to be separate, but since the 1970s they are usually integrated into a single circuit board, known as a microprocessor. This chips alone is enough to satisfy the definition of a computer. The RAM, hard drives, keyboards, mice, graphics cards, and everything else extend this basic computer and give us our modern computers.
Historic Computers
For years and years, the ENIAC was known as the first “modern” computer, released in Novemeber 1945. This massive computer took up an entire room and made use of vacuum tubes and was programmed with patch cables and switches.
There were several attempts before the ENIAC, which was the first machine known to be “Turing complete”. Being Turning complete essentially means that it is capable of performing any mathematical function. There was one computer before the ENIAC that was Turning complete, but it wasn’t proven until 1998. Created in 1941, that computer was the Z3, and is officially the first true “computer”. This computer was programmed by punched film stock.
After these massive, room-sized machines, they progressively grew smaller and smaller. With the advent of the microprocessor in the 1970s, computers grew even smaller. They still continue to grow smaller still.
So, from 1941 to the current year 2008, that means computers as we know them have only existed for less than 70 years. Compared with human history which can be dated all the way back to 2.5 million years, that means we’ve have computers for less than 0.003% of our history. However, in that short amount of time, computers have entirely changed our world, and are still changing the way we live and work.
In this lesson we briefly discussed what it takes to be a computer and discussed a few important advances in computing. In our next lesson, we’ll take a look at how computers work in a bit of detail so we can understand more about what goes on behind the scenes when we program.
