basiccomputerlearn

Basic computer components

A digital computer (see also analog computer) typically consists of a control unit, an arithmetic-logic unit, a memory unit, and input/output units, as illustrated in the figure. The arithmetic-logic unit (ALU) performs simple addition, subtraction, multiplication, division, and logic operations—such as OR and AND. The main computer memory, usually high-speed random-access memory (RAM), stores instructions and data. The control unit fetches data and instructions from memory and effects the operations of the ALU. The control unit and ALU usually are referred to as a processor, or central processing unit (CPU). The operational speed of the CPU primarily determines the speed of the computer as a whole. The basic operation of the CPU is analogous to a computation carried out by a person using an arithmetic calculator, as illustrated in the figure. The control unit corresponds to the human brain and the memory to a notebook that stores the program, initial data, and intermediate and final computational results. In the case of an electronic computer, the CPU and fast memories are realized with transistor circuits.
I/O units, or devices, are commonly referred to as computer peripherals and consist of input units (such as keyboards and optical scanners) for feeding instructions and data into the computer and output units (such as printers and monitors) for displaying results.
In addition to RAM, a computer usually contains some slower, but larger and permanent, secondary memory storage. Almost all computers contain a magnetic storage device known as a hard disk, as well as a disk drive to read from or write to removable magnetic media known as floppy disks. Various optical and magnetic-optical hybrid removable storage media are also quite common, such as CD-ROMs (compact disc read-only memory) and DVD-ROMs (digital video [or versatile] disc read-only memory).
Computers also often contain a cache—a small, extremely fast (compared to RAM) memory unit that can be used to store information that will be urgently or frequently needed. Current research includes cache design and algorithms that can predict what data is likely to be needed next and preload it into the cache for improved performance.

An Introduction to Computer Science
 

Reader, this is Computer Science. Computer Science, this is the Reader.
Well, now that you've met, I'm sure that you will both be good friends. First, however, I think that you'll want to know something about each other.
Theoretical Computer Science has its roots in mathematics, where there was a lot of discussion of logic. It began with Pascal and Babbage in the 1800's. Pascal and Babbage eventually tried to come up with computing machines that would help in calculating arithmetic. Some of them actually worked, but they were mechanical machines built on physics, without a real theoretical background.
Another person in the 1800's was a man named George Boole, who tried to formulate a mathematical form of logic. This was eventually called Boolean Logic in his honor, and we still use it today to form the heart of all computer hardware. All those transistors and things you see on a circuit board are really just physical representations of what George Boole came up with.
Computer Science, however, hit the golden age with John von Neumann and Alan Turing in the 1900's. Von Neumann formulated the theoretical form of computers that is still used today as the heart of all computer design: the separation of the CPU, the RAM, the BUS, etc. This is all known collectively as Von Neumann architecture.
Alan Turing, however, is famous for the theoretical part of Computer Science. He invented something called the Universal Turing Machine, which told us exactly what could and could not be computed using the standard computer architecture of today. This formed the basis of Theoretical Computer Science.
Ever since Turing formulated this extraordinary concept, Computer Science has been dedicated to answering one question: "Can we compute this?" This question is known as computability, and it is one of the core disciplines in Computer Science. Another form of the question is "Can we compute this better?" This leads to more complications, because what does "better" mean?
So, Computer Science is partly about finding efficient algorithms to do what you need.
Still, there are other forms of Computer Science, answering such related questions as "Can we compute thought?" This leads to fields like Artificial Intelligence.
Computer Science is all about getting things done, to find progressive solutions to our problems, to fill gaps in our knowledge. Sure, Computer Science may have some math, but it is different from math. In the end, Computer Science is about exploring the limitations of humans, of expanding our horizons.