Digital era of computers(the saga of computers,part 2)

If you haven't read my previous post about the inception of computer.Please read it from here.

Before the digital computers, all computers were mechanical computers .that means the computer were built using mechanical components likes gears and wheels. They were simple machines that were capable of doing computations.

replica of the first electro-mechanical computer, Image retrieved by www.wikipedia.org

World’s first electro- mechanical was Z1 which was designed by Konrad  Zuse. These were built using Vacuum tubes that can act as a switch in electrical circuits. Z1 is the first computer that used Boolean logic for problem solving. Besides that it was the first computer to use floating point numbers in calculations. Although Z1 used many mechanical components, its design had all the components of a modern digital computer like a control unit, memory unit, and input output devices. Although its outputs weren’t highly reliable .These computer series (Z1, Z2 and Z3) helped to develop most of the theories about computing that are used nowadays. The reason for the unreliability of output data was due to the huge number of mechanical components it had. These mechanical parts mostly consist of metal plates and due to the stresses that occur inside these when in operation, the machine wasn't able to carry out given calculations precisely.

During World War 1 and 2 technological advances was increased like never before because scientists were encouraged to invent new technologies which helped some nations to win war and rise against other nations. Lots of technologies we are familiar nowadays were developed during that period including computer technology. Alan Turing, the famous mathematician who is considered as the father of modern computing laid the mathematical foundations for the digital computers. He theorized a theoretical machine called “Turing machine” which is the grandfather of modern computers, mobile phones embedded systems and almost any digital device you can think of.

During this period scientists were able to design and construct special purpose computers. They were huge machines which consumed lots of power and human effort to operate but this simpler machines were the grandfathers of modern computers. They were called special purpose since they were only built to carry out a special task. Colossus computer is an example for this type of computers. It was built by British military to decode the secret “Enigma” code  which was used in their communications. It was considered as unbreakable but with the help of his machine British army was able to read all German messages and this machine helped to end the 2^nd world war quickly saving many valuable lives.

Picture of the Colossus computer.

 These computers architecture was different to computers now a days. There wasn’t any internal memory for the computer and everything was programmed and programming this computer meant configuring it’s hardware according to the programme they are executing. This was very tedious and time consuming task. As you can see single computer needed a team of operators and only highly trained professionals like engineers or scientists were able to operate it.  

In this time computers were expensive machines due to the high price of it’s hardware ,the transistors were not available and everything was done by using vacuum tubes. As new technologies emerges scientists realised the potential of computer and they built more general purpose machines which could be programmed using softwares and carry out variety of programs .A computer called SSEM was the world’s 1^st stored program computer which was built in 1948.It was a milestone in history of computer science. ENIAC was the 1^st general purpose computer. UNIVAC 1 became the 1^st commercial computer which can be programmed according to the requirements of it’s client.(You can view more details about UNIVAC from here.)

In this time people were more focused on the hardware of the computer since they weren’t cheap and only limited number of manufacturer were there to buy them. With the progress of system design people begun to pay attention to software as well. In the beginning programming was done by using machine language and it was a very difficult task .then people began to use word phrases (mnemonics )to represent a piece of machine code and assembly language was introduced. it made programming much easier but it was still platform dependent and programmers had to programme different types of computers using different assembly languages due to this. They were called low level programming languages because they were just a more human readable version of machine language. So to solve this scientists invented more advanced and abstract programming languages like Fortran , COBOL  and C. They were platform independent and gave much freedom to the programmer to write programs to a computer without knowing it’s architecture. They are called high level languages. These languages made programming a computer much easier but still assembly is very useful since it gives more control of a computer to the programmer and no high level language can directly access hardware of a computer. These high level languages use a special program called compilers to translate the program a programmer wrote to machine code that a computer understand.

In the next post I’m hoping to write the internet era of the computers. Reading the evolution of computers is fun and enjoyable. It may sound like rubbish but there are lots of things to learn from past and we can imagine how the future generation will think about the computers that we use today and I think it won’t be very different from the picture we have in our minds towards the technology about 50 or 60 years ago.