Computer basics (I) Ismail Sangkala (NIDN. 0921018703) Department of English Education Faculty of Education

Part I. Hardware: Physical components of a computer system

Overview of Computers Two systems of computers: 1) PC – the Personal Computer; 2) Mac – the Apple Macintosh. Two designs of computers: Desktop Laptop (notebook) Overview of Computers

Computer architecture Main components of a computer Multimedia devices Other peripheral devices 1)  computer 2)  monitor 3)  hard disk/ hard drive 4)  keyboard 5)  mouse / trackball /      touch pad 1)  CD-ROM / DVD drive 2)  video card 3)  soundcard 4)  speakers 5)  headphones / headset 6)  microphone 1)  printer 2)  scanner 3)  CD- burner (CD- recorder,      CD-R/CD-RW drive) 4)  modem 5)  USB flash drive 6)  webcam 7)  digital camera 8)  digital voice recorder 9)  camcorder Computer architecture

Question 1 Can you divide the above devices into three types – storage devices, input devices, and output devices?

Inside the Computer 1) Processor: The CPU (Central Processing Unit), a complete computation engine that is fabricated on a single chip, is the computer’s brain. It is sometimes referred to as the central processor, microprocessor, or just processor. Two typical components of a CPU are: 1) the arithmetic logic unit (ALU), which performs arithmetic and logical operations, and 2) the control unit, which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary. Most newer PCs have Pentium processors. Pentium processors run faster than the numbered processors found in older computers (286, 386, 486 processors). The speed of processors, called the clock speed, is measured in megahertz (MHz) or gigahertz (1 GHz = 1000 MHz). One MHz represents one million cycles per second. For example, a processor that runs at 200 MHz executes 200 million cycles per second. Each computer instruction requires a fixed number of cycles, so the clock speed determines how many instructions per second the microprocessor can execute. To a large degree, this controls how powerful the processor is.

Inside the Computer 2) Memory ROM (Read Only Memory) is the computer’s permanent, long-term memory. It doesn't disappear when the computer is shut off. It can not be erased or changed in anyway. However, there are types of ROM called PROM that can be altered. The P stands for programmable. ROM's purpose is to store the basic input/output system (BIOS) that controls the start-up, or boot process.  RAM (Random Access Memory) is a working area where the operating system (e.g. Windows), programs and data in current use are kept, ready to be accessed by the processor. It is the best known form of computer memory. However, RAM, unlike ROM, is emptied when the computer is switched off. The more RAM you have, the quicker and more powerful your computer is.

Memory card Memory is measure in the following units:        -  1 byte = 8 bits (Each 1 or 0 is called a bit (i.e. binary digit). Each character (i.e. a letter, a number, a space, or a punctuation mark) has its own arrangements of 8 bits, e.g. 01000001 = “A”, 01000010 = “B”. -  1 KB (kilobyte) = 1024 (210) bytes -  1 MB (megabyte) = 1024 (210) KB -  1 GB (gigabyte) = 1024 (210) MB

Cache (pronounced as "cash") is a buffer (made of a small number of very fast memory chips) between main memory and the processor. It temporarily stores recently accessed or frequently-used data. Whenever the processor needs to read data, it looks in this cache area first. If it finds the data in the cache, then the processor does not need to do more time-consuming reading of data from the main memory. Memory caching allows data to be accessed more quickly.

The most common forms of storage devices in a home computer are: - Hard disk drive - Floppy disk - CD-ROM - CD-R and CD-RW - DVD-ROM - USB flash drives Storage devices

1. Hard disk and hard drive (HD) A hard disk is a magnetic disk on which you can store computer data on a more permanent basis. The term “hard” is used to distinguish it from a soft, or floppy, disk. Hard disks hold more data and are much faster than floppy disks and optical disks. A hard drive is a mechanism that reads and writes data on a hard disk. The capacity of hard drives in newer PCs ranges from 20GB to 60GB in size since all software, from operating systems to word processors, and media files have grown tremendously in size over the last few years.

2. Floppy disk and floppy drive  A floppy disk (often called floppy or disk) is a soft magnetic disk and a floppy drive is a mechanism that reads and writes data on a floppy. Unlike most hard disks, floppy disks are portable, because you can remove them from a disk drive. Floppy disks are slower to access than hard disks and have less storage capacity, but they are much less expensive.         The common size of floppies for PCs made before 1987 was 5¼ inches. This type of floppy was generally capable of storing between 100KB and 1.2MB of data. After 1987 the size reduced to 3½ inches, but the data storage capacity increased, from 400KB to 1.44MB. The most common sizes for PCs are 720KB (double-density) and 1.44MB (high-density).

3. Optical disk and optical drive Optical disks can store information at much higher densities than floppy disks. Thus, they are ideal for multimedia applications where images, animation and sound occupy a lot of disk space. Besides, they are not affected by magnetic fields. This means that they are secure and stable; for example, they can be transported through airport metal detectors without damaging the data. However, optical drives are slower than hard drives. Types: CD-ROM (short for “Compact Disk-Read-Only Memory”) and CD-ROM drive CD-R, CD-RW and CD-R/CD-RW drive (also called CD-burner or CD-Recorder) DVD-ROM (“DVD” is short for “digital video disk” or “digital versatile disk”)

4. USB flash drive A USB flash drive is a small, portable flash memory card that plugs into a computer’s USB port and functions as a portable hard drive with up to 2GB of storage capacity. USB flash drives are easy-to-use because they are small enough to be carried in a pocket and can plug into any computer with a USB drive. In addition, they are very durable because they do not contain any internal moving parts. USB flash drives also are called pen drives, key drives, or simply USB drives. Activity:  Please find your computer’s processor speed, RAM memory size, hard drive capacity, and what storage devices it has. Write down the information!

5. Monitor There are two types of monitors available for PCs: the traditional CRT (cathode ray tube) and the newer LCD (liquid crystal display). The CRT is used for both televisions and computers. It produces a good quality image at a number of different settings for a reasonable price. LCD monitors, also known as flat panel displays, are used in laptop (or notebook) computers and more frequently for desktops as well. They are lighter and smaller (only inches thick) than CRTs with reduced electromagnetic emissions and power consumption.

6. Video Card The card here is a jargon for an electronic circuit board. Video cards are also known as graphics cards, which are responsible for displaying 2D and 3D images on your monitor. 2D graphics are the regular pictures and images that appear on your screen while 3D graphics are mostly used in games and imaging.         Video cards control the resolution of the text, pictures and video that appears on the screen, i.e. the screen resolution (e.g., 800 x 600 pixels, 1024 x 768 pixels). Most modern video cards are accompanied by the software that enables you to control the resolution of the display screen according to the software that you are using. The lower the numbers, the lower the resolution. Remember that getting the video card setting wrong is a common reason for failing to get software to work properly. QUESTION: Do you know where to find the screen resolution and how to set it?

7. Sound Card A sound card is an electronic circuit board that is mounted inside the computer to control sound output to speakers or headphones, to record sound input from a microphone connected to the computer, and to manipulate sound stored on a disk. Sound cards are essential for multimedia applications and have become common on modern personal computers.         A popular make of soundcard is SoundBlaster, which has been the de facto standard sound card. Most sound cards in the past have been Sound Blaster-compatible, which means that they can process commands written for a Sound Blaster card, because most programs that use a sound card have been designed that way. Nowadays, many sound cards are also Windows-compatible. Many multimedia applications require the system to have a Windows-compatible sound card to run properly.

8. ports A port is an interface on a computer to which you can connect a device. Personal computers have various types of ports. Internally, there are several ports for connecting disk drives, monitors, and keyboards. Externally, personal computers have ports for connecting modems, printers, mice, and other peripheral devices. Parallel ports  Serial ports (for most modems and some mice) USB (Universal Serial Bus) ports (for about every peripheral made in a USB version) *Note: A “bus” is a set of conductors that carry signals between different parts of a computer

question 1) What is the memory size of this PC? 2)  How fast is the processor? 3)  What is the capacity of the hard drive? 4)  Which input devices are supplied? 5)  What multimedia features does the computer have? 6)  What operating system does the PC have?     

Web Resources: ICT4LT Module 1.2: Introduction to computer hardware and software: What the language teacher needs to know. How PCs work. http://electronics.howstuffworks.com/pc.htm Computers and how they work. http://www.crews.org/curriculum/ex/compsci/articles/howcomput.ht m Computer lessons for kids and small adults. http://www2.magmacom.com/~dsleeth/kids/lessons/starter.htm Computer training tutorials: Hardware http://www.ckls.org/~crippel/computerlab/tutorials/ How do computers work? Computer basics. http://www.factmonster.com/ipka/A0774696.html