Introduc)on to Compu)ng Heng Sovannarith heng_sovannarith@yahoo.com
Introduc)on Computers play an increasingly important and nearly indispensable role in everyday life. Computers are used all over the world and in all types of environments: businesses, manufacturing environments, homes, government offices and non- profit organiza)ons. These computers can be integrated into devices such as televisions, cash registers, sound systems, and other electronic devices.
Introduc)on (cont.)
Introduc)on (cont.) There are three things that have to work together: 1. Hardware - the physical components, both internal and external, that make up a computer. 2. Opera)ng System - a set of computer programs that manages the hardware of a computer. An opera)ng system controls the resources on a computer, including memory and disk storage. 3. Applica)on SoOware - programs loaded on the computer to perform a specific func)on using the capabili)es of the computer.
Introduc)on (cont.)
Applica)on Applica)ons can be divided into two general categories: Business/Industry SoOware - SoOware designed for use by a specific industry or market. Examples include: medical prac)ce management tools, educa)onal tools and legal sooware. General Use SoOware - SoOware used by a wide range of organiza)ons and home users for various purposes. These applica)ons can be used by any business or individual. Other popular applica)ons include graphics edi)ng sooware and mul)media authoring applica)ons.
Applica)on (cont.)
Applica)on (cont.) In addi)on to Business/Industry and General Use sooware, an applica)on can be classified as local or networked. Local applica)on - A local applica)on is a program, such as a word processor, that is stored on the hard disk of the computer. The applica)on runs only on that computer. Network applica)on - A network applica)on is one that is designed to run over a network, such as the Internet.
Applica)on (cont.)
Classes of Computers There are many different types of computers available including: Mainframes Servers Desktops Worksta)ons Laptops Hand- held portable devices
Classes of Computers
Mainframes Mainframes, on the other hand, are large centralized computers found in sizeable enterprises and purchased through specialized resellers.
Server Servers are high performance computers used in businesses and other organiza)ons. Servers provide services to many end users or clients. Server hardware is op)mized for quick response )me to mul)ple network requests. Servers have mul)ple Central Processing Units (CPUs), large amounts of Random Access Memory (RAM) and mul)ple high capacity disk drives that provide very fast informa)on retrieval.
Desktops support many op)ons and capabili)es. A wide variety of cases, power supplies, hard drives, video cards, monitors and other components are available. Desktops are commonly used to run applica)ons such as word processing, spreadsheets and networked applica)ons such as email and web browsing.
Worksta)on Worksta)ons are high- powered business computers. They are designed for specialized, high- end applica)ons like engineering programs such as CAD (Computer Aided Design).
Portable Device These portable devices vary in size, power and graphic capability and include: Laptop or notebook PC Tablet PC Pocket PC Personal Digital Assistant (PDA) Gaming device Cell phones
Portable Device (cont.)
Representa)on Informa)on Digitally Within a computer, informa)on is represented and stored in a digital binary format. The term bit is an abbrevia)on of binary digit and represents the smallest piece of data. Humans interpret words and pictures; computers interpret only pa_erns of bits. A bit can have only two possible values, a one digit (1) or a zero digit (0). Computers use binary codes to represent and interpret le_ers, numbers and special characters with bits.
Representa)on Informa)on Digitally (cont.) For example: Capital le_er: A = 01000001 Number: 9 = 00111001 Special character: # = 00100011 Each group of eight bits, such as the representa)ons of le_ers and numbers, is known as a byte.. Codes can be used to represent almost any type of informa)on digitally: computer data, graphics, photos, voice, video and music.
Measuring Data Storage Capacity A bit is the smallest representa)on of data 1 Byte = 8 Bits 1 kilobytes (KB) = 1024 Byte 1 megabytes (MB) = 1024 KB 1 gigabytes (GB) = 1024 MB 1 terabytes (TB) = 1024 GB
Measuring Data Storage Capacity (cont.) In general, when something is represented digitally, the greater the detail, the greater the number of bits needed to represent it. A low- resolu)on picture from a digital camera will use around 360KB, and a high- resolu)on picture could use 2 MB or more.
Measuring Speed Data transfer rates are measured in thousands of bits per second (kbps) or millions of bits per second (Mbps). A kbps actually refers to the transfer of 1000 bits of informa)on in one second. For example, how long will it take to transfer a low resolu)on digital photo of 256KB via a 512kbps cable connec)on? First step, convert the file size into bits: 8 x 256 x 1024 = 2097152 bits. 256KB corresponds to 2097 kb. No)ce that the 2097152 is rounded to the nearest 1000. The download )me is then 2097 kb divided by 512 kbps, which equates to approximately 4 seconds.
Computer System Some of the items to consider when purchasing a computer include: the motherboard, processor, RAM, storage, adapter cards, as well as the case and power op)ons.
Motherboard A motherboard is a large circuit board used to connect the electronics and circuitry required which comprise the computer system.
Central Processing Unit Central Processing Unit (CPU) The CPU, or processor, is the nerve center of the computer system. It is the component that processes all of the data within the machine. Processor speed measures how fast a CPU cycles informa)on. It is generally measured in MHz or GHz. The higher the speed the faster the performance. Faster processors consume more power and create more heat than their slower counterparts.
Central Processing Unit (cont.)
Random Access Memory (RAM) RAM is a type of data storage used in computers. It is used to store programs and data while being processed by the CPU. All computer programs run from RAM. Besides the CPU, the amount of RAM is the most important factor in computer performance
Adapter Card Adapter cards add func)onality to a computer system. Some of the more common adapter cards include: Video cards Sound cards Network interface cards Modems Interface cards Controller cards
Adapter Cards (cont.)
Storage Devices Magne)c Storage Magne)c storage devices are the most common form found in computers. These devices store informa)on in the form of magne)c fields. They include: Hard disk drives Floppy drives Tape drives
Storage Devices (cont.) Op)cal Drives Op)cal storage devices use laser beams to record informa)on by crea)ng differences in op)cal density. These devices include CDs and DVDs and come in three different formats: Read only: CD, DVD Write once: CD- R, DVD- R Write many: CD- RW, DVD- RW Most computers now incorporate DVD- RW drives that can store approximately 4.7 GB of data on a single disc. Disks are called Blu- ray, to dis)nguish them from conven)onal DVDs which use a red laser. Blu- ray disks have storage capaci)es of 25 GB and more.
Storage Devices (cont.)
Peripheral Devices A peripheral is a device that is added to the computer to expand its capabili)es. These devices are op)onal in nature and are not required for the basic func)oning of the computer. Instead they are used to increase the usefulness of the machine. Peripheral devices are connected externally to the computer using a specialized cable or wireless connec)on.
Peripheral Devices (cont.) Peripheral devices can fit into one of four categories: input, output, storage or networking devices. Examples of some common peripherals include: Input devices - trackball, joys)ck, scanner, digital camera, digi)zer, barcode reader, microphone Output devices - printer, plo_er, speakers, headphones Storage devices - secondary hard drive, external CD/ DVD devices, flash drives Networking - external modems, external NIC
Peripheral Devices (cont.)
Peripheral Devices (cont.)
Case and Power Supply The case and power supply are usually sold together as a unit. The power supply must be sufficient to power the system and any devices that are added to it in the future.
Uninterrup)ble Power Supplies (UPS) In order to help protect the computer system from these power problems, devices such as uninterrup)ble power supplies (UPS) has been developed. A UPS is a device that con)nually monitors the power to a computer system and maintains the charge on an internal ba_ery. If the power is interrupted, the UPS provides backup power to the system without interrup)on.
Uninterrup)ble Power Supplies (UPS) (cont.)
Opera)ng System The OS acts like a translator between user applica)ons and the hardware. A user interacts with the computer system through an applica)on, such as a word processor, spreadsheet, computer game or instant messaging program. Applica)on programs are designed for a specific purpose, such as word processing, and know nothing of the underlying electronics. For example, the applica)on is not concerned with how informa)on is entered into the applica)on from the keyboard.
Opera)ng System (cont.) The opera)ng system is responsible for the communica)on between the applica)on and the hardware When a computer is powered on, it loads the OS, normally from a disk drive, into RAM. The por)on of the OS code that interacts directly with the computer hardware is known as the kernel. The por)on that interfaces with the applica)ons and user, is known as the shell. The user can interact with the shell using either the command line interface (CLI) or graphical user interface (GUI).
Opera)ng System (cont.)
Opera)ng System (cont.) Purpose of an Opera)ng System Opera)ng systems have complete control of local hardware resources. They are designed to work with one user at a )me. They enable the user to mul)task. The opera)ng system keeps track of which resources are used by which applica)on.
Opera)ng System (cont.) There are many different opera)ng systems available. The major groupings are listed here with some examples. MicrosoO Windows: XP, Vista, 2003 Server UNIX- Based: IBM AIX, Hewle_ Packard HPUX, and Sun Solaris BSD - Free BSD Linux- Based (Many varie)es) Macintosh OS X Non- Unix Proprietary: IBM OS/400, z/os
What is a Network? There are many types of networks that provide us with different kinds of services. In the course of a day, a person might make a phone call, watch a television show, listen to the radio, look up something on the Internet, or even play a video game with someone in another country. All of these ac)vi)es depend on robust, reliable networks. Networks provide the ability to connect people and equipment no ma_er where they are in the world. People use networks without ever thinking about how they work or what it would be like if the networks did not exist.
What is a Network? (cont.)
What is a Network? (cont.) Communica)on technology in the 1990s, and before, required separate, dedicated networks for voice, video and computer data communica)ons. Each of these networks required a different type of device in order to access the network. Telephones, televisions, and computers used specific technologies and different dedicated network structures, to communicate. But what if people want to access all of these network services at the same )me, possibly using a single device?
What is a Network? (cont.) Here are other uses of a network and the Internet: Sharing music and video files Research and on- line learning Chapng with friends Planning vaca)ons Purchasing gios and supplies Can you think of other ways people use networks and the Internet in their daily lives?
What is a Network? (cont.)