The Book of the World is digital

"The World is digital" is the world's top computer scientist Brian W. Kernighan. an introductory book for ordinary readers. This book is easy to understand and interesting, and many views are of great value to both professionals and the general public.

First, what is in the computer

CPU:CPU is the processor or CPU, the brain of the computer. The operation that the processor can perform is limited, but it is very fast, up to billions of times per second. It can find out what instructions to follow in the previous calculation.

RAM: The main memory, the random access memory, which holds the information that the processor and other parts of the computer are using, and the CPU can change the contents. Memory not only saves the data that the CPU is working on, but also saves the instructions that the CPU needs to execute.

Disk and mass storage: the capacity of the memory is large, but it is limited, and the content disappears after the RAM is powered down. High-capacity memory can still keep the information inside after a power outage. The most common mass storage is a disk, sometimes referred to as a hard drive, or a hard drive. Disk saves more information than memory, and is not easy to lose, that is, the information on the disk, whether power or power is always there.

Second, bit, byte and information representation

Bit: The digital system uses numeric values to represent all information, but uses binary instead of the familiar decimal. The most basic unit for representing digital information is the bit (bit). With only one bit, you can represent any two-choice thing. For example: On/Off, true/false, yes/no, etc. One bit is enough to make sure which one of the two is selected. For example, "1" means to open, with "0" to express the off.

Bytes: The basic unit of data processing and memory organization is 8 bits. 8 bits are called 1 bytes, and one byte can encode 256 different values, which can be integers from 0 to 255, or it can be one character in the ASCII character set, or something else.

Third, in-depth understanding of the CPU

The RAM is slower than the CPU operation. The most recently used instructions and data are stored between the CPU and ram through a small amount of high-speed memory, which is called caching. The CPU has a small instruction system that contains the basic operations it can perform. It can do arithmetic problems, add, subtract, multiply, divide, and like a calculator. It can get the data to be manipulated from RAM and then save the results in RAM. In addition to the CPU to control other components of the computer, to report the mouse, keyboard and other input data to be responsive, let the information on the screen, but also public office and coordination of all other devices connected to the computer.

Most important it can make a decision: it can compare values of laughter and can decide what to do next based on the results. This means that the CPU can do much more than a calculator, but it can do its job unattended.

In fact, although I am a software engineering students, but I would like to accompany the computer is not very understanding, I just know how to operate it. Until I read this book, the contents of the book is easy to understand, even the layman can understand, but also let me know more about my future needs of the computer often together. Let me benefit.

The Book of the World is digital