CPU the easy way – Part 1 (Von Neumann architecture)

Ok, so you have just started studying Computer Science or a similar study and you are now learning about Von Neumann architecture. You might be asking yourself “Why do we care about this in year 2015?”
Well, trust me, you do care.
The details about the architecture is very well documented and you find dozens of articles covering it on-line, but I’m trying to break things in smaller pieces for those who find it difficult to understand.

The Von Neumann architecture was founded by John von Neumann in 1945 (that’s 70 years ago). John was a mathematician and researcher from Hungary who was living in the US. He is the one that described how a computer is able to store instructions and data in the same memory. This also includes your Smart phone and probably the device you are reading this text on.
In the early days of computing, instructions and data were stored in separate memories. You had to “re-wire” the whole thing with switches and wires to do different tasks. So with this “stored-program concept” in place, people could focus more on programming stuff on the computers instead of designing them. It is important to understand that John did not invent the computer’s memory or the CPU, but the architecture.
The architecture has five parts:

  • Arithmetic/Logic Unit (ALU)
  • Control Unit
    (these two are inside the physical CPU chip)
  • Memory
  • Bus
  • Some form of input and output

Great! now you know some basic but important parts of the history of early computing.
In the next part of this series, we will dig a bit deeper into the world of CPU and see how it is all glued together. We will also look into some of the limitations and challenges we are having today with the Von Neumann architecture. This is known as the Von Neumann bottleneck.
Continue to Part 2

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