Sahalsoftware college. Welcome To understanding Basic Computer Concept

Transcription

1 Welcome To understanding Basic Computer Concept 1

2 Chapter1: Understanding Computer Concepts What is a computer? A computer is a machine that takes in data, processes if following a set of instructions and then produces results. Data can come in many forms such as: Numbers Text Pictures Sounds. The computer is able to store instructions on the process to be carried out so that it can undertake the task automatically. In contrast to humans, computers can do this accurately, with great speed, and do not get tired. Although there are many different types of computer, when we think of a computer we usually think of a personal computer a general purpose machine that is used to create letters, play games, and send e- mails and so on. In fact, computers can now be found virtually everywhere. Types of Computer: 1. Super Computers 2. Mainframe Computers 3. Mini Computers 4. Personal Computers What makes up a computer system? A computer system consists of and Software. Computer equipment that you can touch and handle is called. This is the name given to all the physical devices that make up the computer system. These include the input devices (Used to get the information into the computer). 2

3 Input Devices Processing Devices Storage Devices Output Devices Chapter 2: Input Devices: A hardware device that sends information into the CPU (Central Process Unit). Without any input devices a computer would simply be a display device and not allow users to interact with it, much like a TV. Below is a listing of different types of computer input devices, such as: 3

4 Input Devices Keyboard Mouse Digital Camera Scanner Microphone Keyboard: Enhanced keyboard with 101 key: One of the main input devices used on a computer, a PC's keyboard looks very similar to the keyboards of electric typewriters, with some additional keys. Below is a graphic of the keyboard with indicators pointing to each of the major portions of the keyboard The keys on computer keyboards are often classified as follows: 4

5 Alphanumeric keys : Letters and numbers Punctuation keys : Coma, Period, semicolon and so on. Special keys : Function keys, control keys, arrow keys, Caps lock, key. Mouse: Mouse is a device that controls the movement of the cursor or pointer on a display screen. Its name is derived from its shape, which looks a bit like a mouse. Mice contain at least one button and sometimes as many as three, which have different functions depending on what program is running. Some newer mice also include a scroll wheel for scrolling through long documents. The mouse is important for graph. Digital Camera: A type of camera that stores the pictures or video it takes in electronic format instead of to film. There are several features that make digital cameras a popular choice when compared to film cameras. First, the feature often enjoyed the most is the LCD display on the digital camera. This display allows users to view photos or video after the picture or video has been taken, which means if you take a picture and don't like the results, you can delete it; or if you do like the picture, you can easily show it to other people. Another nice feature with digital cameras is the ability to take dozens, sometimes hundreds of different pictures. 5

6 Scanners: Scanners have become an important part of the home office over the last few years. Scanner technology is everywhere and used in many ways. The basic principle of a scanner is to analyze an image and process it in some way. Image and text capture allow you to save information to a file on your computer. Then you can allow your image print it out, or you can send everywhere. Chapter 3: Processing Devices: Computers take input through input devices like keyboard and mouse. Every action on or by the input devices are converted into electromagnetic signals. These electrical signals are sent to Signal Processing Units. Below is a listing of different types of computer processing devices, such as: 6

7 Processing Devices Motherboard CPU Power Supply 7

8 Motherboard:- The main circuit board of a computer is called the motherboard. This contains sockets that accept additional boards. In a desktop computer, the motherboard contains the CPU, chipset, PCI bus slots, AGP slot, memory sockets and controller circuits for the keyboard, mouse, disks and printer. It may also have built-in controllers for modem, sound, display and network, obviating the need to plug in a card. A laptop motherboard typically has all peripheral controllers built in. 8

9 Power Supply If there is any one component that is absolutely vital to the operation of a computer, it is the power supply. Power Supply is the heart of computer. Without it, a computer is just an inert box full of plastic and metal. The power supply converts the alternating current (AC) line from your home to the direct current (DC) needed by the personal computer. In a personal computer (PC), the power supply is the metal box usually found in a corner of the case. The power supply is visible from the back of many systems because it contains the powercord and the cooling fan. Power supplies, often referred to as "switching power supplies", use switcher technology to convert the AC input to lower DC voltages. The typical voltages supplied are: 3.3 volts 5 volts 12 volts CPU The CPU, or Central Processing Unit, is the Brain of a computer. It's what does the work in adding two numbers together or moving a string of text from one location to another. CPU usage indicates how much of a workload is being handled by the CPU. A load of 100% means that processor is fully utilized, whereas a load of 50% means that it's sitting idle half the time. 9

10 Chapter 4: Storage Devices: A storage device is a hardware device designed to store information. There are two types of storage devices used in computers; a 'primary storage' device and a 'secondary storage' device. Primary storage device A storage location that holds memory for short periods of times. For example, computer RAM is an example of a primary storage device. Unlike ROM (Read Only Memory). RAM (Read Access Memory) RAM is used for the computer s immediate access memory. The larger the amount of this fastaccess RAM, the less often the computer is forced to change information with its slower/cheaper memory devices when running demanding applications programs. This is also one of the reasons why applications may function more slowly when the number of applications running (and thus demands on RAM s) is increased. Therefore, in general the more RAM the computer has, the faster applications will run. Unfortunately, RAM needs electricity to retain information; any information stored will be lost when the power is turned off. A typical basic PC might have 512 MB of RAM. Secondary storage device 10

11 A storage medium that holds information until it is deleted or overwritten. Such as ROM Hard Disk Drive (Drive C) Floppy Disk (Drive A) CD-Room DVD Room Flash Drive MP3 or 4 ROM (Read Only Memory) ROM permanently stores instructions and data even when the power is turned off. The computer s BIOS (Basic Input Output System). Is stored in ROM. Hard disk (HDD) Most computers use one or more hard disks. A hard disk is used as the main permanent store of programs that have been loaded on to the computer so that they are always available. Hard disks are also used as the main storage location for folders and files that you have created. Hard disk capacity is currently measured in gigabytes (GB). Typical hard disk capacity is 100 GB to 400 GB. Floppy disk (FDD) A floppy disk (sometimes known as a FDD) is a removable 3.5. That you can easily insert and remove from a disk drive on the front of your computer. Floppy disk access is slower compared with a hard disk but provides a convenient and cheap way of backing up (saving a copy of) or transferring relatively small amounts of data. However, Floppy disks are gradually being phased out of new computer systems. Floppy disk capacity is currently measured in megabytes (MB). Typical Floppy disk capacity is 1.44 MB. CD-ROM CD-ROM (Compact Disk Read Only Memory) disk is a flat optically read device with data. CD- 11

12 ROM provides a cheap way of backing up or transferring large amounts of data. Single CD-ROM can hold in access of 600 MB, equivalent the content of five hundred floppy disks. As the size of Operating systems and Applications Software has increased, these are now usually distributed on CD-ROMs instead of Floppy disks. A CD-R: is a recordable CD that can be recorded on once only. A CD-RW: is recordable and can be used many times and costs less than one pound. DVD (Digital Versatile disk) A DVD is a high-speed, ultra-high capacity (about 5 GB) flat optical storage like CD-ROM. It can store full-length feature films on a single disk. Cost is significantly higher than for a CD-ROM. 12

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20 Chapter 6: What is the difference between Data and Information? Data is information that has no meaning. Suppose walks up to you and gives you a piece of paper with written on it. The number could mean absolutely anything. They might be telling you their birthday, or how much money you owe them, or they might be giving you their phone number. Data only became information when you know the context of the data. Information = Data + Meaning. How computers Process Data: Computers are machines that process data. Computers run electricity. They consist of a number of electric circuits, and each circuit can be in one of only two states: on or off. Computers use a binary code to represent data. A circuit that is switched on represents the digit 1, and a circuit that is switched off represents the digit 0. Bit Each individual 1 or 0 1 Byte = 8 Bits 1 KB (Kilobyte) = 1024 Bytes 1 MB (Megabyte) = 1024 KB 1 GB (Gigabyte) = 1024 MB 1 TB (Terabyte) = 1024 GB 1 PB (Pet byte) = 1024 TB Each character from the keyboard is given an 8-bit (i.e. 1 byte) ASCII code (American Standard Code for Information Interchange). For example presents the Number 200. Binary Code (Machine Language) Normally binary numbers are usually read digit-by-digit, in order to distinguish them from decimal numbers. For example, the binary numeral 100 is pronounced one-zero-zero, rather than one hundred. 20

21 For example: To convert from a base-10 integer numeral to its base-2 (binary) equivalent, the number is multiplying by two the nearest number, and the remainder is the least-significant bit, theinteger result is again multiplying by two; its remainder is the next most significant bit. This process repeats until the result of further multiplication becomes zero. For example, 6-base 10, in binary, is: Operation 6 = 2* = 2* = 2*0+1 6 =

22 Another example, 200-base 10, in binary, is: 200 = 2 * = 2 * = 2 * = 2 * = 2 * = 2 * = 2 * = 2 * = Connection:- A term used describes the physical location of where another peripheral is connected to the computer. For example, your monitor, mouse, and keyboard all must connect to a computer before they will be able to work. Below is a picture of the back of a standard desktop computer and each of its connections. Although you re desktop computer's layout may be different, this diagram will give you a better understanding of where everything connects. 22

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