11COMPUTERHARDWARETECHNOLOGIES© Abdou Illia, Fall 2012(August 27, 2012)2LEARNING GOALS Identify the major components of modern PCs Explain the role of the components of a computer system; Explain input devices and how they operate. Describe output devices and how they operate. Describe I/O (secondary storage) devices and how they operate. Explain the role of the CPU and the RAM. Describe various types of computers.3The Core Computer Components Four subsystems in a computer system:1. Input subsystem 3. Output subsystem2. Processing subsystem 4. I/O (Storage) subsystemInputProcessOutputInput/Output (storage)24Input subsystem Main functions:  Allowing the user to enter data Converts data into electronic form Transmitting data to the Processing subsystem Includes keyboard, mouse, etc. Question: Name five other input devices ____________________________ ____________________________ ____________________________ ____________________________ ____________________________5Input Devices Human input devices Allow a person to enter data to the computer User involvement needed Examples: Keyboard, Mouse, Stylus Machine-readable input devices Send data directly to computer w/o human involvement No human involvement means no human error Usually faster than human input Examples: Bar codes reader, Optical Characters Recognition (OCR) system, sensors6Machine-readable Input Devices Bar code scanners Uses light to read series of coded stripes Universal Product Code, European Article Number Optical Character Recognition (OCR) Includes OCR Software and scanner Translates scanned digital image to character that user can recognize and manipulate Magnetic Ink Character Recognition (MICR) Character recognition technology used by banks to allow rapid routing of checks between banks37Output subsystem Main function: Show processing results Includes monitor, printer, etc. Q: Name two other output devices ____________________________ ____________________________8Output Devices Monitors’ Technology Cathode ray tube (CRT) Liquid crystal displays (LCD) and TFT-LCD Organic Light Emitted Diode (OLED) Better contrast and better viewing angles compared to LCD (1920x1080, 2560x1440) Quality of display Resolution; e.g. 640 x 480 pixels Dot pitch in millimeters (e.g. .22, .25, .26) Active-Matrix vs. Passive-Matrix display Viewing angles  Touch screens:  input and output via display deviceVideo Card ResolutionColor Graphics Adapter CGA (1981) 640×200Hercules (1984) 720×348 Extended Graphics Array XGA (1990) 1024×768 Super XGA 1280×1024 Ultra XGA 1600×1200 9Printers Speed and resolution Pages per minute (PPM) Dots per inch (DPI) Number of ink dots to fill a square inch Higher DPI = greater page clarity Impact printers Create image by striking paper and ribbon Dot-matrix printers = most common impact printers Non-impact printers Create image by spraying or rolling ink on the pageThe laser printer uses electrostatic charges to (1) create an image on the drum, (2) adhere toner to the image, (3) transfer the toned image to the paper, and (4) fuse the toner to the paper. The laser creates the image by "painting" a negative of the page to be printed on the charged drum. Where light falls, the charge is dissipated, leaving a positive image to be printed.410Non-impact Printers Ink-jet technology printers Spray ink on the paper Quiet Color is readily and cheaply available Laser printers Laser heats drum which rolls ink (toner) on paper Can be faster than ink-jet More expensive than ink-jet11I/O or Secondary Storage devices Secondary compared to the main primary memory called RAM  Nonvolatile1storage of digital data - Could be Magnetic, Optical,  Magnetic storage (data stored on magnetically coated surface) Examples: Magnetic tape, Hard disk, floppy disk Sequential access (e.g. tape) or direct access (e.g. HDD) HDDs are electromechanical devices with spinning disks and movable disks Use standards/interfaces like• Parallel ATA (PATA) or IDE (Integrated Drive Electronics)• Serial ATA (SATA)2• SCSI (Small Computer System Interface) SCSI provides disk fault-tolerance by using RAID – Redundant Array of Inexpensive Disks; that is multiple disks set together to provide continued service in case one disk fails. Disk speed:• Transfer rate in MBps (Megabytes per second) or GBps• Average Read Time (in milliseconds or ms)• Platter rotation speed in RPM (5400/7200/10,000/15,000) State Solid Disks (SSD) use microchips which retain data in non-volatile memory chips No moving parts | Have lower access time and latency Can replace your existing HDD if same interface1. Means that the stored data wouldn’t disappear (or be deleted) in case of power shortage2. In SATA and PATA, ATA stands for Advanced Technology Attachment256GB Crucial m4 2.5-inch SATA 6GB/s12Optical Secondary Storage Optical laser beans used for reading data Compact disks (CDs) Standard 12 cm or mini CD (8 cm) 650-700 MB standard or 185–210 MB (mini) CD-ROM: Read-Only CD CD-R: Recordable CD (recordings designed to be permanent) CD-RW: Read-Write or Re-recordable CD Digital versatile disks (DVDs) 2 – 17 GB capacity DVD-RAM DVD-/+R DVD-/+RWSingle layer capacityDual/Double layer capacityPhysical size GB GB GB GB12 cm, single sided 4.7 4.38 8.5 7.9212 cm, double sided 9.4 8.75 17.1 15.938 cm, single sided 1.4 1.30 2.6 2.428 cm, double sided 2.8 2.61 5.2 4.84513Data Storage units14Processing subsystem Motherboard: chipset that all components connect to Two major components in processing subsys. CPU (Central Processing Unit) or Processor(s) Primary Storage: Random Access Memory (RAM) Read Only Memory (ROM)Busses that transfer dataCPUPrimary StorageOthercomponentson the Motherboard15Central Processing Unit Clock: generate time that synchronize other components ICU: Fetches instructions from RAM ALU: Execute instructions (arithmetic & logic operations) Registers: Store control information, data, intermediate resultsProcessorClockInstruction Control UnitArithmetic Logic UnitRegisters616CPU speed Speed measured in hertz Hertz = # of instructions executed per second Megahertz = 1 million of instructions per second Gigahertz = 1 billion of