What is a computer?
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- Device Interfaces/ Controllers A device controller
- SCSI is the Small Computer System Interface
- TYPES OF INPUT Keyboard
- Alphanumeric Keyboard
- Both are used in creating architectural designs . SOURCE Data Entry Devices
- Image processing systems
- Optical Codes
- Optical Mark Recognition (OMR)
- Magnetic Ink Character Recognition (MICR)
- Digital Camera
Flash Memory Cards A memory card or flash card is an electronic flash memory data storage device. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players and video game consoles. These cards are of varying sizes, and each is available in a range of storage capacities. Device Interfaces/ Controllers A device controller is a part of a computer system that makes sense of the signals going to, and coming from the CPU. Any device connected to the computer is connected by a plug and socket, and the socket is connected to a device controller or cable. Device controllers use binary and digital codes. A device's controller functions as a bridge between the device and the operating system. SCSI is the Small Computer System Interface It is mostly used for storage devices, such as disks, tapes, but also includes communications devices, printers, and scanners. A USB port allows a Universal Serial Bus (USB) device to become accessible to a host computing device, to enable file transfers between the two. To the host device, the USB device appears similar to an external hard drive, enabling drag-and-drop file transfers. USB provides an interface to a variety of storage devices. Some of the devices that are connected to computers via this standard include: hard drives , flash memory devices, digital cameras, PDAs, mobile phones I  DE/ATA now called Parallel ATA (PATA), originally AT Attachment, is an interface standard for the connection of storage devices such as hard disks, floppy drives, and optical disc drives in computers. The technology normally appears as an internal computer storage interface.
Serial ATA (SATA) is a computer bus interface for connecting computers to mass storage devices such as hard disk drives and optical drives. Serial ATA was designed to replace the older AT Attachment standard (ATA). It has several advantages over the older interface: reduced cable size and cost, faster data transfer , and more efficient transfer. INPUT DEVICES & MEDIA I  nput is the process of entering data, programs, commands, and user responses into main memory. Input Devices refers to the media that transmits these input types to the computer system.
TYPES OF INPUT Keyboard: A device, resembling a typewriting machine that users use to input data to a computer by pressing the keys on the keyboard. Keyboards are connected to the other devices that have screens such as a personal computer or terminal. Users enter data through the keyboard, the data displays on the screen. Alphanumeric Keyboard A very common, general purpose, input device that allows text (abc…), numbers (123…) and symbols (%$@...) to be entered into a computer. A keyboard is simply a set of buttons. Each button has a binary code assigned. Braille Keyboard-has letters and symbols raised in Braille so the blind can use. N  umeric Keypad-Is a small keyboard that only has numbers. It is used to enter numeric data into computers such as those in ATMs. Most computer keyboards have a numeric keypad on the right side, and most mobile phones (they are also computers) have a one for entering phone numbers, etc.
PIN Pad This is a device with a numeric keypad used to enter a person’s Personal Identity Number (PIN) e.g. when paying with a credit card. PIN pads are also found on electronic door locks – you enter a PIN to unlock the door. Mouse: A small, lightweight input device that easily fits in the palm of your hand. Movement along a flat surface, such as a desktop to controls the movement of the pointer on a screen. The mouse is usually attached to the computer by a cable but wireless mouse devices exist. Track Ball This is a pointing device like a mouse, only with the ball on the top of the device instead of the bottom. To move the device with a trackball, all you have to do is rotate the ball in the desired direction. Smaller trackball units have been designed for use on portable computers. J  oystick
This is a device which uses the movement of vertical stem, to direct the pointer. Full-size joystick usually have buttons you press to activate certain events, depending on the software. PEN INPUT DEVICES Pen input devices allow the user to use a pen in three different ways; To input data using hand-written characters and shapes the computer can recognize. As a pointing device like a mouse to select items on the screen To gesture (special symbols made with the pen that issue a command such as delete text. Almost all of the personal digital assistant (PDA) class of computer uses a pen or stylus. Light Pen A device used by touching it on the display screen to create or modify graphics. A light cell in the tip of the pen censes light from the screen to determine the pen’s locations. The light can be used to select processing options to draw on the screen. Touch Screen: A device, which allows the user interacts with a computer by the touch of a finger rather than typing on a keyboard or moving a mouse. The user enters data or commands by touching words or numbers of locations identified on the screen. Touch screens have been successfully installed in kiosks (computers terminals set up in public places to provide information in hotels, airports, and other public locations). Digitizer Pad Used to converts points, lines and curves from sketch, drawing, or photograph to digital signals and transmit them to a computer. The user indicates the data to be input by pressing one or more buttons on the hand-held digitizer device. Graphics Tablet: Works in similar manner to a digitizer (Converts points, lines and curves from sketch, drawing, or photograph to digital signals), but it also contains unique characters and commands that can be automatically generated by the person using the tablet. Both are used in creating architectural designs. SOURCE Data Entry Devices Source data automation equipment captures data directly from its original source, such as an invoice, or an inventory tag. Image /Page Scanner: An input device that electronically captures an entire page of text, or images such as photographs or artwork. The scanner converts the text or image on the original document into digital information that can be stored on a disk, printed or displayed separately or merged into another document such as newsletter. Image processing systems use scanners to capture and electronically file documents such as legal documents or documents with signatures or drawing. These systems are like electronic filing cabinets that allow users to rapidly access and review exact reproductions of the original documents. Optical Recognition A device, which uses a light source to read codes, marks, and characters and convert them into digital data that can be processed by a computer. Optical Codes: - uses a pattern or symbols to represent data. The most common optical code is the Bar code. A Bar Code consists of a set of vertical lines and spaces of different widths. The bar code is usually either printed on the product package or attached to the product with a label or tag. A bar code reader uses the light pattern from the bar code lines to identify the item. The most familiar is the Universal Product Code (UPC). The UPC bar code, used for grocery and retail items, can be translated into ten-digit number that identify the product manufactured and number. Optical Mark Recognition (OMR): A device often used to process questionnaires, lottery tickets or multiple choice answer sheets. Carefully placed marks on the form indicate responses to questions that are read and interpreted by a computer program. Optical Character Recognition (OCR) These are scanners that read typewritten, computer printed, and handwritten characters from ordinary documents. An OCR scans the shape of a character, compares it with a predefined shape stored in memory, and converts the character into the corresponding computer code. OCR is frequently used for turnaround documents. E.g. billing statements from credit card companies, department stores, utility companies (light, telephone & water). Magnetic Ink Character Recognition (MICR): A device which uses special ink that is magnetized during processing. MICR is used almost exclusively by the banking industry for processing checks. Checks already have the bank code, account number and check number printed in MICR characters across the bottom. When the bank processes the check, the amount of the check is also printed in the lower right corner. Together, MICR reader-sorter machines read this information as part of the check-clearing process. Digital Camera This device captures digital photographs. Most digital cameras do not directly input data into a computer - they store photographs on memory cards. The photographs can later be transferred to a computer. Video Camera This device captures moving images, or video. Like a digital camera, most video cameras do not directly input data into a computer – the captured movies are stored on video-tape or memory cards and later transferred to a computer. However, there are some situations where video cameras do feed video data directly into a computer: television production and video-conferencing. In these situations the video data is required in real-time. Web Cam This is a very basic video camera used to feed live video into a computer. The video data from a web cam is low quality compared to a full video camera. However it is good enough for web chats (e.g. using a messenger application such as MSN Messenger or Skype). Microphone An input device that converts sound into a signal that can be fed into a computer. The signal from a microphone is usually analogue so, before it can be processed by a computer, it must be converted into digital data. An Analogue-to-Digital Convertor (ADC) is used for this (usually built into the computer’s sound card) Many headphones now come with microphones to allow them to be used with chat and phone applications Biometric Input: Devices used to capture biographic characteristics such as fingerprints or palm print scans, facial scan, retina scan (eyes), voice recognition etc. Used to establish identity and provide security. S  ensors - A sensor is a device that converts a real-world property (e.g. temperature) into data that a computer can process.
Remote control- These devices are very common. They send data signals each time a button is pressed using infrared light or radio signals. The signals can control a computer (or a system that contains a small computer such as a DVD player) from some distance. Download 2.81 Mb. Share with your friends:
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