The Book of the World is digital

This book shows me the History of computer development, From the first Joseph Mary Jacquard to our familiar Turing, the author of the computer did a perfect surgical operation, the history of the computer, structure, the use of the development of a clear display in front of us, let me more deeply aware of how we live in a world, this is the digital era, we at the center of this era, the world is changing high Rapid development, our current will become the next generation of the past, the first chapter of the hardware Let me know the main part of the digital computer is the processor and memory, the storage contains the instructions to use the processor and other important things, instructions and data to be differentiated by different occasions, One's instruction can make another person's data, according to Turing said, today's computer and the original computer in computing power is exactly the same, of course, their performance naturally is different, the development of computers mainly in the rain let it faster, bigger, more functional, see here, I understand the computer has deepened a layer, , the author not only use vivid metaphor to help us to understand the computer more deeply, when talking about the interest in the time will also recommend some interesting small software, such as the eighth chapter introduces to us the origin of the network and the development process also mentions a software called Wireshark, The use of this software can help us to understand why on the Ethernet to all the information encryption and the security of the Internet, which I can not see in college classes to hear.

In this book I also see a lot of once or doubts, or smattering of the proper terminology, the most impressive is the cellular phone in the origin of the word, mobile phone is called the cellular phone is because the band and radio coverage is limited, it is necessary to divide the entire area into honeycomb-like many communities, Each such cell can be imagined as a hexagon, and then each hexagon has a base station, adjacent to the cell through the base station connected, when the phone, the hands of the nearest base station communication, when the user moved to another community, the call from the original community to a new community, However, this switching user is generally not aware of, because the receiving power will decay with the distance of two times, so the frequency band in the given frequency band can be reused in the adjacent cell, without interfering with each other, which is the secret of efficient use of the limited frequency band.

When it comes to computers that naturally cannot ignore the derivative of the Internet, as people are asked to meet each other by computer, people start to want to share, so the network will be born, from the initial telephone line to the current gigabit fiber, video, pictures, text, these information carriers in order to be able to travel through the network, I was exposed to the concept of analog and digital signals, and I noticed that the world was the meaning of the headline, yes, as people constantly update and improve the computer, basically everything can be converted to digital, in the computer's eyes, we see, hear can be converted into numbers, I believe, In the near future, we can also touch the number to achieve!

Why is mobile phone called "Cellular phone"?

What is "honeycomb"? Because the band and radio coverage are limited, it is necessary to divide the entire area into honeycomb-like communities. It is possible to imagine each such cell as a hexagon and then a base station in the center, adjacent to the cell connected by the base station. When making a phone call, the hand has the opportunity to communicate with the nearest base station. when the user moves to another cell, the ongoing call is transferred from the original cell to the new community, but this switching user is generally not aware of.
Since the received power will decay with the distance of two times, the frequency bands in the given frequency band can be reused in the adjacent cell without interfering with each other. This is where the secret to efficient use of the limited band is.

The Book of the World is digital