HOW A COMPUTER PROCESSES DATA

What is hardware? Hardware is the electric, electronic and mechanical equipment that makes up a computer What is software? Software is the series of instructions that tells the hardware how to perform tasks What is input and input devices? Any data or instructions which you enter into the computer What is output and output devices? Output is data that has been processed into information

What is a computer? An electronic machine  operates under the control of instructions stored in its own memory  can accept data  manipulates the data according to specified rules  produces results and  stores the results for future use

Who is a computer user? A user is someone who communicates with a computer or uses the information it generates. What is data? Data is a collection of unprocessed facts, figures and symbols What is information? Information is data that is organized, meaningful and useful

How a computer process data? Processing is the thinking that the computer does - the calculations, comparisons, and decisions. People also process data. What you see and hear and touch and feel is input. Then you connect this new input with what you already know, look for how it all fits together, and come up with a reaction, your output. "That stove is hot. I'll move my hand now!".

The kind of "thinking" that computers do is very different from what people do. Machines have to think the hard way Complex procedures must be broken down into VERY simple steps

Processing components

Computers processes data The CPU, or Central Processing Unit, is the part of the computer where work gets done. In most computers, there is one processing chip.

ALU ALU stands for Arithmetic/Logic Unit This is the part that executes the computer's commands. A command must be either a basic arithmetic operation: + - * / or one of the logical comparisons: >< =not= Everything has to be broken down into these few operations. The ALU can only do one thing at a time but can work very very fast.

Main Memory Main Memory stores the commands that the CPU executes and the results. This is where the computer stores the data and commands that are currently being used. When the computer is turned off, all data in Main Memory vanishes. A data storage method of this type is called volatile since the data "evaporates." The CPU can fetch one piece of data in one machine cycle.

Control Unit This is the part of the computer that controls the Machine Cycle. It takes numerous cycles to do even a simple addition of two numbers. The Machine Cycle Fetch -get an instruction from Main Memory Decode -translate it into computer commands Execute -actually process the command Store -write the result to Main Memory

OPERATING SYSTEM Operating System This is the instructions that the computer uses to tell itself how it "operates". It's the answer to "Who am I and what can I do?" Some common operating systems are DOS, various versions of Windows, OS/2, UNIX, LINUX, System 7. These all behave in very different ways and have different hardware requirements. So they won't all run on all machines.

Application Applications These are the various programs that are currently running on the computer. By taking turns with the Machine Cycle, modern computers can have several different programs running at once. This is called multi-tasking.Machine Cycle Each open application has to have some data stored in Main Memory, even if the application is on rest break and is just sitting there.

Input/Output Input/Output Storage When you enter new data, the keystrokes must be stored until the computer can do something with the new data. When you want data printed out or displayed, it must be stored somewhere handy first.

Working Storage Working Storage The numbers and characters that are the intermediate results of computer operations must be stored until the final values are calculated. These values "in progress" are kept in temporary locations. For example, if the computer is adding up the numbers 3, 5, and 6, it would first add 3 to 5 which yields a value of 8. The 8 is stored in working storage. Then the 8 and 6 are added and the new value 14 is stored. The value of 14 is now available to be displayed on the screen or to be printed or to be used in another calculation.

Unused storage Unused Storage One hopes that there is always some storage space that is not in use. If space runs out in Main Memory, the computer will crash, that is, stop working.