Input to the Computer * Input * Keyboard * Pointing Devices * Source Data Automation * Terminals * Multimedia Input Devices * Data Accuracy Input to Computer

Components of a Computer System Second Memory Input Device Output Device CPU CU ALU Primary Memory Market Share Input Processing Output CPU: Central Processing Unit ALU: Arithmetic Logic Unit CU : Control Unit Overview of Computer Concepts

Input * Input Input refers to the process of entering data, programs, commands, and user responses into main memory of the computer. * Types of Input - Data: raw facts, including numbers, letters, words, images, and sounds. - Programs: instructions that direct the computer. - Commands: key words and phrases that the user inputs to direct the computer to perform certain activities. - User responses: the data that a user inputs to respond to a question or message from the software. Input to Computer

Keyboard * Keyboard is a common input device of computers. * Traditional Keyboard similar to a typewriter * Untraditional Keyboards - McDonald’s Keyboard - Chinese character keyboard * Data Entry Operators who use computer terminals to enter large amounts of data from source documents. Input to Computer

Pointing Devices (1) * Mouse * Trackball * Joystick * Pen Input Devices * Touch Screen * Light Pen * Digitizer * Graphics Tablet Input to Computer

Pointing Devices (2) * Mouse a computer input devices that actually looks a little bit like a mouse. * Pointer (Cursor) a flashing indicator on a screen that shows where the next user-computer interaction will take place. * Icon a pictorial symbol on a screen. A computer user can interact with an icon by using a mouse. Input to Computer

Pointing Devices (3) * Trackball a variation of the mouse. To move the cursor, the user rolls a ball that is embedded in the top of the trackball devices. * Joystick A Joystick uses the movement of a vertical stem to direct the pointer. * Pen Input Devices Pen input devices allow the user to use the pen to input hand-printed letters and numbers to record information. * Touch Screen A touch screen allows users to touch areas of the screen to enter data. Input to Computer

Pointing Devices (4) * Light Pen A light pen is used to touching it on the display screen to create or modify graphics. * Digitizer A digitizer converts points, lines, and curves from a sketch, drawing, or photograph to digital signals and transmits them to a computer. * Graphics Tablet A graphics tablet converts points, lines, and curves from a sketch, drawing, or photograph to digital signals and transmits them to a computer. It also contains unique characters and commands that can be automatically generated by the person using the tablet. Input to Computer

Source Data Automation (1) * Image Scanner * Optical Recognition - Optical Mark Recognition (OMR) - Optical Character Recognition (OCR) - Handwritten Characters - Bar Codes * Magnetic-Ink Character Recognition ( MICR) * Data Collection Devices * Voice Input ( Speech Recognition) Input to Computer

Source Data Automation (2) the use of special equipment to collect data at the source and send it directly to the computer. Input to Computer

Image Scanner - Source Data Automation (3) * What is an image scanner? An image scanner, also called Page Scanner, is an input device that electronically captures an entire page of text or image such as photographs or art work. * How does an image scanner work? The scanner converts the text or image on the original document into digital information that can be stores on a disk and processed by the computer (Image Processing System). Input to Computer

Optical Recognition- Source Data Automation (4) Optical Mark Recognition (OMR) * What is Optical Mark Recognition? Optical Mark Recognition (OMR) uses a light beam to recognize marks on paper. * What are OMR used for? OMR devices are often used to process questionnaires or test answer sheets. Input to Computer

Optical Recognition- Source Data Automation (5) Optical Character Recognition (OCR) * OCR Device OCR device uses a light beam to read special characters. * OCR-A OCR-A is a common standard font for optical character recognition. * Wand Reader Wand Read is a popular input device for reading OCR-A. Input to Computer

Optical Recognition- Source Data Automation (6) Handwritten Characters * Handwritten Characters Devices Handwritten Characters devices can read handwritten characters by optical recognition techniques. * Legibility of Handwritten Characters - Make your letters big - Use simple shapes - Use block printing - Connect lines - Close loops - Do not link characters Input to Computer

Optical Recognition- Source Data Automation (7) Bar Code Reader * Optical Codes Optical codes use a pattern or symbols to represent data. * Bar Code (the most common optical code) A bar code consists of a set of vertical lines and spaces of different widths. * Bar Code Reader Bar Code Reader is a stationary photoelectric scanner used to input a bar code, the pattern of vertical marks that represents the Universal Product Code (UPC) that identifies a product. Input to Computer

MICR - Source Data Automation (8) Magnetic-Ink Character Recognition (MICR) Magnetic-Ink Character Recognition (MICR) involves characters made of magnetized particles. The characters are put on documents (bank checks) by MICR inscribers and are read by MICR reader/sorters. Input to Computer

Data Collection Devices - Source Data Automation (9) * Data Collection Devices allow direct, accurate data entry in places. * Data Collection Devices are designed and used for obtaining data at the site (factories) where the transaction or event being reported takes place. Input to Computer

Voice Input (Speech Recognition) Voice is the process of presenting input data to the computer through the spoken word * Speech Recognition Devices Speech Recognition Devices convert spoken words into a digital code that a computer can understand. * Digital Signal Processor (DSP) DSP changes sound into the digital form understood by computer. * Discrete Word Systems require speakers to pause between words. * Continuous Word Systems allow a normal rate of speaking. Input to Computer

Terminals *Terminals Terminals (display terminals, or video display terminals) consist of a keyboard and a screen. * Dumb Terminal Dumb terminal does not process data. * Smart Terminal Smart terminal can do some processing, usually to edit data it receives. * Intelligent Terminals Intelligent terminals can be programmed to perform a variety of processing functions. Intelligent terminals have built-in processing capabilities and have also secondary storage devices such as disk drives. Input to Computer

Multimedia Input Devices Multimedia is the combination of sound and image with text and graphics. * Sound Input such as Electronic music keyboard * Voice Input such as Speech-to-text system * Digital Camera Captures digital image * Video Input Converts video into digital data Input to Computer

Data Accuracy * GIGO GIGO stands for Garbage In , Garbage Out. Because inaccurate information caused by inaccurate data is often worse than no information at all. * Data Tests before Processing - Tests for data type and format - Tests for data reasonableness - Tests for data consistency - Tests for transcription and transposition errors Input to Computer