A Typical PC and Computer Systems PDF

## A Typical PC ### Computer Essentials - Speaker - Webcam - Monitor - Software, e.g., Word Processor - CD/DVD Drive - CPU (Central Processing Unit, inside) - Printer - Keyboard - Mouse - Modem ### Parts of a Computer A computer is an electronic machine that accepts, processes, stores and output...

## A Typical PC ### Computer Essentials - Speaker - Webcam - Monitor - Software, e.g., Word Processor - CD/DVD Drive - CPU (Central Processing Unit, inside) - Printer - Keyboard - Mouse - Modem ### Parts of a Computer A computer is an electronic machine that accepts, processes, stores and outputs information. A typical computer consists of two parts: hardware and software. - Hardware is any electronic or mechanical part of the computer system that you can see or touch. - Software is a set of instructions, called a program, that tells a computer what to do. There are three basic hardware sections: 1. **The CPU:** The heart of the computer, a microprocessor chip which processes data and coordinates the activities of all other units 2. **The Main Memory:** Holds the instructions and data which are being processed by the CPU. It has two main sections: RAM (random access memory) and ROM (read only memory) 3. **Peripherals:** The physical units attached to the computer. They include: - **Input Devices:** Let us enter data and commands (e.g., the keyboard and the mouse) - **Output Devices:** Let us extract the results (e.g., the monitor and the printer) - **Storage Devices:** Used to store information permanently (e.g., hard disks and DVD-RW drives) Disk drives are used to read and write data on disks. At the back of a computer there are ports into which we can plug external devices (e.g., a scanner, a modem, etc.). They allow communication between the computer and the devices. ### Functions of a PC: Input, Processing, Output, Storage | Function | Description | |---|---| | Input | We enter data with a keyboard, a webcam, etc. | | Processing | The data is manipulated according to program instructions. | | Output | We can see the result on the screen or in printed form. | | Storage | We keep data and programs in memory systems where they are available for processing. | ## Types of Computer Systems ### From Mainframes to Wearable Computers - **Mainframe:** The most powerful type of computer. It can process and store large amounts of data. It supports multiple users at the same time and can support more simultaneous processes than a PC. The central system is a large server connected to hundreds of terminals over a network. Mainframes are used for large-scale computing purposes in banks, big companies and universities. - **Desktop PC:** Has its own processing unit (or CPU), monitor and keyboard. It is used as a personal computer in the home or as a workstation for group work. Typical examples are the IBM PC and the Apple Macintosh. It's designed to be placed on your desk. Some models have a vertical case called a tower. - **Laptop:** A lightweight computer that you can transport easily. It can work as fast as a desktop PC, with similar processors, memory capacity, and disk drives, but it is portable and has a smaller screen. Modern notebooks have a TFT (Thin Film Transistor) screen that produces very sharp images. Instead of a mouse, they have a touchpad built into the keyboard - a sensitive pad that you can touch to move the pointer on the screen. They offer a lot of connectivity options: USB (Universal Serial Bus) ports for connecting peripherals, slots for memory cards, etc. They come with battery packs, which let you use the computer when there are no electrical outlets available. - **Tablet PC:** Looks like a book, with an LCD screen on which you can write using a special digital pen. You can fold and rotate the screen 180 degrees. Your handwriting can be recognized and converted into editable text. You can also type at the detached keyboard or use voice recognition. It's mobile and versatile. - **PDA:** A tiny computer which can be held in one hand. The term PDA refers to a wide variety of hand-held devices, palmtops and pocket PCs. For input, you type at a small keyboard or use a stylus - a special pen used with a touch screen to select items, draw pictures, etc. Some models incorporate handwriting recognition, which enables a PDA to recognize characters written by hand. Some PDAs recognize spoken words by using voice recognition software. They can be used as mobile phones or as personal organizers for storing notes, reminders and addresses. They also let you access the Internet via wireless technology, without cables. - **Wearable Computer:** Runs on batteries and is worn on the user's body, e.g., on a belt, backpack or vest, and is designed for mobile or hands-free operation. Some devices are equipped with a wireless modem, a small keyboard and a screen; others are voice-activated and can access email or voice mail.