Mr. K Hinds 3 rd Form CSEC IT Section 1 IT Syllabus : Page 1. Definitions Information

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1 2018: Page 1 Definitions Information Data The term Information refers to any meaningful communication or representation of knowledge; These include things such as facts, data or opinions in any medium, including textual, numerical, graphical, narrative or audio-visual forms. Data is raw unorganized information converted into electrical signals or electromagnetic pulses for transmission along a communication medium. Communication Technology This is the transmission of data or information from a sender to a receiver through a medium. Technology is the practical form of scientific knowledge or the science of application of knowledge to practical. What is Information and Communication Technology? Information and Communication Technology is the total system used for communications; encompassing all human resources, modern and antiquated technological infrastructure and communication pathways for transmission and usage of information. What is Information Technology? Information Technology is the usage of computers to store, retrieve, transmit, and manipulate data, or information. Information Technology is a subset of Information and Communications Technology

2 2018: Page 2 Complete the table below, comparing the features of the computers listed and their properties Computer Type Processing Speed Storage Portability Super Computers e.g. Cray; Built for large computing and transactional processes in the scientific and industrial applications; e.g. NASA Astrology and Rocket Science Main Frames e.g. IBM zenterprize System; Built for huge transaction processing in business environments e.g. Airline Check In System Peta FLOPS (Floating Point Operations per Second) Millions of Instructions per Second (MIPS) Petabyte Storage Units Terabytes Not Portable Not Portable Desktop Systems Used for personal computing Giga Hertz (GHz) Gigabytes Low Portability Mobile Devices e.g. Laptops, Tablets, Phones, etc. Highly personalized computing devices Mega Hertz (MHz) Gigabytes and Megabytes Highly Portable Embedded Devices e.g. Answering Machines Car Ignition Systems & Microwaves Kilo Hertz (KHz) Megabytes and Kilobytes Low Portability & Bulky

3 2018: Page 3 Functions of Major Hardware Components of a Computer System Information Processing Cycle A computer system is capable of four basic major operations: Input, Processing, Storage and Output. Input This process relates to the entering of data into the system using INPUT DEVICES. (Keyboard, joystick, mouse, etc.). Processing and Storage The system takes the input data and immediately begins to work on it. The system uses mathematical and logical processes to compute a solution, sometimes transferring data back and forth between the Storage Unit until the assigned task is completed. After the system computes a final solution from the processing node, the computed solution is saved to the storage device. This storage device can be internal hard drive space, a flash drive or any other storage medium. Output This process displays the results from the Processing node to an OUTPUT DEVICE. (Screen, printer, speakers, etc.)

4 2018: Page 4 Central Processing Unit (CPU) The CPU is responsible for managing all tasks, computations and operations within the computer system. This task is so complicated that we need to look at exactly how this is done. The CPU is made of five interdependent units: Input, Arithmetic/Logical Processing Unit, Memory, Control Unit and Output. The Arithmetic Logic Unit (ALU) performs simple arithmetic and logical operations. The control unit (CU) manages the flow of information across the CPU. It reads and interprets instructions from memory and transforms them into a series of signals to activate other parts of the computer. The control unit calls upon the Arithmetic Logic Unit to perform the necessary calculations. Third is the Memory but because it resided within the CPU, we refer to it as Cache. This serves as high-speed memory where instructions can be copied to and retrieved.

5 2018: Page 5 Primary Storage: RAM and ROM Read Only Memory (ROM): The contents of ROM is permanent. It cannot be altered by the user. The content is written onto the ROM when it is first made. ROM keeps its contents even when the computer is turned off and so is known as non-volatile memory. On some computers a special piece of software called the operating system is stored in ROM. ROM is also often used in embedded systems where a small built-in computer is used to control a device such as a washing machine. The program that controls the machine is stored on ROM. Random Access Memory (RAM): RAM is used to store programs and data that are being used by the computer. When the computer is turned on the RAM is empty. Data and programs can be put into RAM from either an input device or backing store. The data in RAM is lost when the computer is turned off, so it is known as volatile memory. To keep data the user must save it to backing store before the computer is turned off. Secondary Storage Devices Alternatively referred to as external memory, secondary memory, and auxiliary storage, a secondary storage device is a non-volatile device that holds data until it is deleted or overwritten. Secondary storage is usually cheaper than primary storage per byte. Consequently, hard drives (a prime example of secondary storage) are the go-to solution for nearly all data kept on today's computers. Hard Disk A hard disk is a set of stacked disks. Each disk has data recorded electromagnetically in concentric circles, or tracks, on the disk. A head sits above the disk but in a relatively fixed position and writes or reads the information on the tracks. Two heads, one on each side of a disk, read or write the data as the disk spins. Each read or write operation requires that data be located, an operation called a seek. Magnetic Tape It uses a long strip of narrow plastic film with tapes of thin magnetizable coating. It is essentially a device which records or perhaps plays back video and audio using magnetic tape, examples of which are tape recorders and video tape recorders. Flash Drive A USB flash drive is a device used for data storage that includes a flash memory and an integrated Universal Serial Bus (USB) interface. Most USB flash drives are removable and rewritable. Physically, they are small, durable and reliable. The larger their storage space, the faster they tend to operate. USB flash drives are mechanically very robust because there are no moving parts. They derive the power to operate from the device to which they are connected (typically a computer) via the USB port. Memory Card This is a small, flat flash drive used especially in digital cameras and mobile phones.

6 2018: Page 6 Optical Disk An optical disc is an electronic data storage medium that can be written to and read from using a low-powered laser beam. CD: A Compact Disc is a portable storage medium that can be used to record, store and play back audio, video and other data in digital form. A standard compact disc has a capacity of 80 minutes of audio or 700 MB of data. Digital Video Disc (DVD): DVD is an optical disc technology with a 4.7 gigabyte storage capacity on a single-sided, one-layered disk, which is enough for a 133-minute movie. DVDs can be single or double-sided and can have two layers on each side; a double-sided, two-layered DVD will hold up to 17 gigabytes of video, audio, or other information. This compares to 700 megabytes of storage for a CD-ROM disk. Blu-Ray: Blu-ray is an optical disc format designed to display high definition video and store large amounts of data. Blu-ray is the successor to DVD. The format's name comes from the fact that a blue laser reads from and writes to the disc rather than the red laser of DVD players. A Blu-ray disc can store much more data in the same 12 centimeter space. Like the rewritable DVD formats, Blu-ray uses phase change technology to enable repeated writing to the disc. Blu-ray's standard storage capacity is enough to store a continuous backup copy of most people's hard drives on a single disc. Initially, the format had a 27 gigabyte (GB) single-sided capacity and 50 GB on dual-layer discs.

7 2018: Page 7 Units of Storage Bits: This is either a pulse or no pulse, defined as wither a 1 or 0. This is the most basic form of data on a computer Byte: A byte consists of eight bits. Unit Symbol Meaning bit b 0 or 1 Byte B 8 bits Kilobytes (kb) kb 1024 B Megabytes (MB) MB 1024 kb Gigabytes (GB) GB 1024 MB Terabytes (TB) TB 1024 GB Types of Storage Local Storage: Local Storage includes physical hardware such as external hard drives, flash drives, and CDs. Cloud Storage: Refers to any program owned by a third party that allows you to upload your data using the Internet Comparison of Local vs Cloud Storage Type of Storage Local Storage Capacity Cost Accessibility Security Issues Cloud Storage

8 2018: Page 8 Application of Input and Output Devices Input Devices Optical Mark Reader (OMR): An OMR is a scanning device used to capture input from cards and other predefined documents. The OMR scans the document and checks for a difference in density of marks on the page at various locations and compares it to a master file for processing. Multiple choice questionnaires are usually corrected with OMR s. Optical Character Reader (OCR): These devices scans documents and gives a digital editable copy of the same document, thereby eliminating the need to retype the entire document. Magnetic Ink Character Recognition (MICR): Mouse: Joystick: MICR is a technology used to verify the legitimacy or originality of paper documents, especially checks. Special ink, which is sensitive to magnetic fields, is used in the printing of certain characters on the original documents. Information can be encoded in the magnetic characters. If a document has been forged - for example, a counterfeit check produced using a color photocopying machine, the magnetic-ink line will either not respond to magnetic fields or will produce an incorrect code when scanned using a device designed to recover the information in the magnetic characters. This is a device used by the user to select options and navigate items visually on the computer screen This is a device used with graphical software to capture analogous user input Bar Code Reader: A barcode reader, also called a point-of-sale ( POS ) scanner, is a device used to capture and read information contained in a bar code. A barcode reader works by directing a beam of light across the bar code and measuring the amount of light that is reflected. (The dark bars on a barcode reflect less light than the white spaces between them.) The scanner converts the light energy into electrical energy which is understood by the computer. Document Scanner: This is a device used to make digital copies of physical documents. The Document Scanner scans the document using a photo sensitive cover plate and a high intensity light source.

9 2018: Page 9 Light Pen: A light pen is a light-sensitive computer input device, that is used to select text, draw pictures and interact with user interface elements on a computer screen or monitor. Touch Terminals: A touch screen terminal allows the user to directly interact with the device without secondary equipment like a mouse or keyboard. It does not need a stylus Voice Response Units: Touchscreens Keyboard: A voice response unit (VRU) is an automated telephone answering system consisting of hardware and software that allows the caller to navigate through a series of prerecorded messages and use a menu of options through the buttons on a touch-tone telephone or through voice recognition These are display devices that allows a user to interact with a computer by touching areas on the screen. Three main touchscreens are Point-of-Sale Terminals, Tablets and ATM s Point of Sale: This is a complete system found in supermarkets and other retail environments which includes devices captures the transaction using a variety of devices which include computers, cash registers, optical and bar code scanners, magnetic card readers, or any combination of these device Tablet: A tablet is a wireless touch screen personal computer (PC) that is smaller than a notebook but larger than a smartphone Automated Teller Machine (ATM): These are devices that allow us to conduct automated financial transactions using a screen that responds to our touch. This device is used to capture text and numerical data from the user Digital Camera: This device is used to capture photographs and transfer them to the computer Biometric Systems: Sensors: These systems use biological information from the user to access some service with a computer. Biometric devices include eye scanners, finger print readers and voice recognition. A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

10 2018: Page 10 Remote Control: This is a small portable device used to control the computer through a Bluetooth, wireless or infrared controller. Sound Capture: Sound Capture is a digital recording of sound waves; such as spoken voice, singing, instrumental music or sound effects. Pointing Devices: Webcam: These devices are used in conjunction with a computer to allow the user to select various items on a screen by pointing the pen at various objects on a screen or onto a device. The pen emits a beam of light that is shone onto objects to read barcodes or onto a light sensitive screen to capture user input. This is a visual device that captures the video of the user of the computer.

11 2018: Page 11 Visual Display Unit (VDU) A VDU displays images generated by a computer or other electronic device. The term VDU is often used synonymously with "monitor," but it can also refer to another type of display, such as a digital projector. Visual display units may be peripheral devices or may be integrated with the other components. VDU sizes are measured diagonally from one end of the screen to the next. Types of Monitors Cathode Ray Tube (CRT s) The image on a CRT display is created by firing electrons from the back of the tube to phosphors located towards the front of the display. Once the electrons hit the phosphors, they light up and are projected on the screen. The colour you see on the screen is produced by a blend of red, blue, and green light, often referred to as RGB. The stream of electrons is guiding by magnetic charges, which is why you may get interference with unshielded speakers or other magnetic devices that are placed close to a CRT monitor. CRT s are usually small in size since the electron gun needs to be further from the screen to produce a larger image on larger screens. Therefore, larger screens need lots of room and can become bulky. Flat Screen (Plasma, LCD, LED) A Plasma display illuminates tiny, coloured fluorescent lights to form an image. Each pixel is made up of three fluorescent lights -- a red light, a green light and a blue light. Just like a CRT television, the plasma display varies the intensities of the different lights to produce a full range of colours. Plasma screens work by exciting tiny pockets of gas (Xenon and Neon), changing them to a plasma state. In that state, the electrons of that gas emit ultraviolet light, which is not visible to the human eye. The ultraviolet light is then absorbed and re-emitted into the visible spectrum of light by the phosphor inside each cell. Each pixel consists of three sub pixels: one red, one blue, and one green. The more excited the gas, the brighter the colour produced. The pixel is not excited continuously, but in short pulses. The naked eye perceives this as flickering. Some people are very sensitive to this. The effect is reduced on higher-end models because the flickering is a lot faster. Because each pixel emits its own light, the blacks are really deep. When the television wants to display black, it simply emits no light at all for the selected pixels. Plasmas suffer from occasional image retention if they display the same image for a very long period of time. LCD Stands for "Liquid Crystal Display." LCDs are super-thin displays that are used in laptop computer screens and flat panel monitors. Smaller LCDs are used in handheld TVs, PDAs, and portable video game devices. The screen is composed of two parts: the actual liquid crystal display and a light source at the back of the screen (called backlight). A light diffuser is placed between the backlight and the LCD screen to make the source of light uniform across the screen. The LCD screen does not emit light by itself; it only acts as a filter to block the light on a per pixel basis. The opacity of a pixel can be controlled by applying an electric field to it. If the screen wants to display black, the LCD pixel will try to block the light completely. If it wants to display white, it will let it through. Because the display is only a filter, the blacks will not be as deep as with a plasma screen. An LCD pixel, even if it displays black, will always let through a small portion of the light.

12 2018: Page 12 LED screens are an LCD screen that uses light-emitting diodes (LEDs) as a source of light behind the screen. An LED is more energy efficient and a lot smaller than the lighting mechanism used in a LCD screen, enabling a thinner television screen. Since it is only the backlight that changed, there is no picture quality improvement over a normal LCD screen.

13 2018: Page 13 Printers A printer is a device that produces a physical copy of text and graphics on the computer screen. Printers need supplies to work, which is referred to as consumables. These include standard sizes of paper and ink. Printers come in many sizes and operating functionalities. Impact and Non-Impact Printers Impact printers include all printers that work by striking an ink ribbon. Daisy-wheel, dotmatrix, and line printers are impact printers. Daisy-wheel: Similar to a ball-head typewriter, this type of printer has a plastic or metal wheel on which the shape of each character stands out in relief. A hammer presses the wheel against a ribbon, which in turn makes an ink stain in the shape of the character on the paper. Daisy-wheel printers produce letter-quality print but cannot print graphics. Dot-Matrix: Creates characters by striking pins against an ink ribbon. Each pin makes a dot, and combinations of dots form characters and illustrations. Non-impact printers do not strike any ink ribbons and as such are usually quieter than their impact counterparts. Ink-Jet: Line Printer: Laser: LED: Sprays ink at a sheet of paper. Ink-jet printers produce high-quality text and graphics. Ink-Jets prints letter by letter. Contains a chain of characters or pins that print an entire line at one time. Line printers are very fast, but produce low-quality print. Laser printers produce very high quality text and graphics. It does this by printing page by page which take less time to print the overall document that an ink-jet would. These are non-impact but use a light-emitting diode instead of a laser in the print head. LED printers function by focusing light across the entire length of the drum, thus creating areas that are less charged, which attracts toner. The printer then transfers the toner from the drum to the paper and applies intense heat to fuse the toner to the paper. Thermal Printer: Plotters: An inexpensive printer that works by pushing heated pins against heat sensitive paper. Thermal printers are widely used in calculators and fax machines.

14 2018: Page 14 3D Printers: Microfilm: Audible Output Speakers: A plotter is used for printing vector graphics. Instead of toner, plotters use a pen, pencil, marker, or another writing tool to draw multiple, continuous lines onto paper rather than a series of dots like a traditional printer. Plotters are used to produce a hard copy of schematics and other similar applications. 3D printing is a process of making three dimensional solid objects from a digital file. An object is created by laying down successive layers of material until the object is created. 3D printing enables the production of complex (functional) shapes using less material than traditional manufacturing methods. This is also called microphotography, consists in the reduction of images, books, newspapers and other printed materials to such a small size that they cannot be read without optical assistance. This amazing photographic compression often results in a ninety-nine percent saving of space. The microfilming service is one of the most extensively used and common practices in modern reprographic science. A hardware device connected to a computer's sound card that outputs sound generated by the computer. Head-Phones/Earphones: Computer Software Sometimes referred to as earphones, headphones are a hardware device that either plugs into your computer (line out) or your speakers to privately listen to audio without disturbing anyone else. Computer Software is divided into two categories; Application software and System Software Application Software is used to take user input and then perform a specific function directly for the user or, in some cases, for another application. Examples of application programs are Microsoft Office, Adobe reader, games, Chrome and Flash Player. System Software are used to control the hardware of the computer system and provide a platform for application programs to run on. Examples of system programs are operating systems (Windows 7, Windows Server 2012, Macintosh, Android and Linux) as well as Programmable Language Software and Data Backup.

15 2018: Page 15 User Interfaces Hardware Interface Specialized Keyboard These are special user interfaces that help machine operators and engineers interact with a wide range of automated or semi-automated equipment. These devices use alphanumeric buttons or sensors coded to specific input data that is relayed into a computer system, machine interface, or operational network. These specialized tools can be configured with a broad assortment of features, with many different combinations designed to meet the needs of specific industrial applications. Touch Screens These are an extension of a GUI. In addition to displaying a graphical user interface, users can interact with icons on the screen by directly touching them to activate them. The screen uses a touch sensitive screen that responds to human fingers alone. Software Interface Command Line This is a textual interface provided by some computers for users interacting with it. All information entered in to the computer is done through typing the commands into the computer and the computer executes the command immediately as the enter key is pressed. An example of a Command Line interface is Command Prompt on a Windows computer. Graphical User Interface (GUI) This is a visual interface that is presented to the user of the computer to obtain their input or inform them about an ongoing process. The computer screen that you are looking at now has a GUI and it is displayed on the screen in front of you. Your ability to use the mouse and select objects on the screen is also a part of the functionality of the GUI. Text, images, videos and multimedia are capable of being shown on a GUI. Touch Interfaces These allow visually impaired users to interact with the computer. This can be done using sensors that are placed around the computer to capture the movement of the user s hands; for those using sign language. Additionally, Braille keyboards are used to capture user input on the keyboard. Menu Driven This is an interface consisting of a series of screens which are navigated by choosing options from lists, i.e. menus. ( Menu is not used here to refer to pull-down menus, but to lists of options on the screen that lead to other screens.) Due to their simplicity, menu-driven interfaces are commonly used for walk-up-and-use systems, such as

16 2018: Page 16 information kiosks and ATMs. Websites are also often designed with the same basic navigation principle, where navigation bars substitute for menus. End of Third Form Syllabus Outline