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Behind the well-known screen and keyboard of a personal computer, lies a complex labyrinth of technology. Commands are executed quicker than the blink of an eye. Multiple activities are juggled adroitly, so that users are hardly aware of the number of balls in the air simultaneously. The computer manages to refresh the screen, display the time, check for keystrokes and mouse activity, manage Internet connections and even send data to the printer. It all happens so smoothly that people tend to take it for granted. So, how does a computer accomplish all of this?
In the heart of the computer lies the CPU, or the Central Processing Unit. This is the command center, where the basic level activities occur and decisions are made.
Within the CPU are two parts. The Control Unit fetches and decodes items from memory. Based on what it finds, the Control Unit decides what to do with it and what to do next. -
The other half of the CPU is the Arithmetic/Logic Unit, which processes what the Control Unit hands it and sends out the results. The CPU exists to follow instructions, which come from a variety of sources. There is constant communication between the CPU and memory locations where both data and instructions are stored. Some of the instructions involve operating on data in a certain memory location. Other instructions may direct toward a different memory location for further instructions.
The CPU is a microprocessor chip; this physical device is an example of what is call "hardware." When people use a computer, what they interact directly with is called "application software." By contrast, software is a tool for you to use. One example of a software application is Microsoft Word. -
Software is "soft" in that it is not physical. Software consists of another set of instructions and data. This would be a long and complicated set of instructions and a large heap of data, but if you boil it all down, that's what software applications amount to. Software applications are installed onto the hard drive and are available all the time for use.
Beneath all the application software is the operating system. This provides the functioning infrastructure for the entire computer, both hardware and software. Within the operating system is a middleman that coordinates operations between the CPU, memory, external devices and various applications. This manager is called the kernel. It synchronizes communication and to a certain extent manages memory usage.
The most used types of memory are the hard drive and RAM. RAM (Random Access Memory) exists on an integrated circuit card. Each memory cell may be located by its unique row/column address. The hard drive is similar to several spinning stacked DVD/CD discs with enough space between them for a read-write head to access memory addresses.
