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Introduction to Computer Science (I) Inside the Computer T. K. Yin, NUK-CSIE Computer System • A computer system consists of – Hardware: The set of electronic elements required to run programs – Software: The set of instructions to be run on the hardware – Data: Raw facts as input to the computer. After processed, useful information as the output of the computer is produced – User T. K. Yin, NUK-CSIE Binary Digits: 1 and 0 • Types of signals – Analog: Continuous waveforms in which variations in frequency and amplitude can be used to represent information – Digital: Discrete signals in two states. Generally, the on state is expressed or represented by the number 1 and the off state by the number 0 T. K. Yin, NUK-CSIE • Digitalized data in computers – – – – – – Letters Numbers Colors Sounds Images Odors • Bit: An on or off electronic state – On-bit: 1 – Off-bit: 0 T. K. Yin, NUK-CSIE • On and off states inside the computers – RAM: Presence or absence of an electrical charge in an integrated circuit T. K. Yin, NUK-CSIE Source: http://www.intel.com/research/silicon/nanotechnology.htm – Disk storage: Two states are represented by the magnetic arrangement of the surface coating on magnetic disks Source: http://www.research.ibm.com/resources/news/20010518_whitepaper.shtml T. K. Yin, NUK-CSIE – CD and DVD: Digital data are stored permanently as microscopic pits Source: http://www.opticaldisc-systems.com/2002SepOct/DVDBASICS80.htm T. K. Yin, NUK-CSIE – Fiber optic cable: Binary data are pulses of light – Electrical transmission media: Binary numbers are electrical signals Source: http://www.bsu.edu/web/CBTHORNBERRY/trends5.html T. K. Yin, NUK-CSIE • Character encoding systems: bits and bytes – Byte: The 8-bit combination of bits are used to represent a character – ASCII: The 7-bit ASCII (American Standard Code for Information Interchange) code can represent up to 128 characters T. K. Yin, NUK-CSIE Source: http://www.unicode.org/charts/PDF/U0000.pdf – Unicode: A 16-bit encoding system to represent more characters than the English language Source: http://www.unicode.org/charts/PDF/U4E00.pdf T. K. Yin, NUK-CSIE The Components of A Computer • Von Neumann architecture – The model of computing proposed by John Von Neumann (1903-1957) in 1946 – The stored program computer • The instructions that control the operation of the computer be encoded as binary values and stored internally in the memory unit along with the data – The basis of the structure and organization of virtually all modern computers T. K. Yin, NUK-CSIE – Include four major subsystems called memory, input/output, the arithmetic/logic unit (ALU), and the control unit Memory Control unit ALU T. K. Yin, NUK-CSIE Processor Memory – The first stored program • Maurice Wilkes of the University of Cambridge created the first stored program on a machine, called EDSAC, which calculated and printed the table of squares on May 6, 1949. Image courtesy of Computer History Museum, http://www.computerhistory.org T. K. Yin, NUK-CSIE • The major devices of a personal computer – – – – The PC system unit Storage devices Input devices Output devices Storage Devices Input Devices T. K. Yin, NUK-CSIE CPU Control Unit ALU Main Memory System Unit Output Devices The PC System Unit • The motherboard – A single circuit board provides the path through which the processor communicates with memory components and peripheral devices – Attached devices • • • • Processor Support electronic circuitry, such as the chipset Memory chips Expansion boards T. K. Yin, NUK-CSIE 1: Processor socket 2: DIMM sockets 6 1 7 3. Floppy connector 4: Hard disk connectors 5: Chipset 5 2 6: PCI expansion slots 7: AGP video cord slot 4 T. K. Yin, NUK-CSIE Source: http://www.asus.com 3 1: PS/2 mouse port 7: USB 2.0 ports 1 and 2 2: Parallel port 8: VGA por 3: RJ-45 port 9: S/PDIF out port (digital audio) 4: Line In port 10: USB 2.0 ports 3 and 4 5: Line Out port 11: PS/2 keyboard port 6: Microphone port T. K. Yin, NUK-CSIE Source: http://www.asus.com • The processor – Called the central processing unit or CPU – The nucleus of any computer system – Contains the control unit and the arithmetic and logic unit – Companies • • • • • • Intel: Pentium 4, Celeron, Xeon, Itanium Motorola: 680x0 AMD: K6, Duron, Athlon Apple/Motorola/IBM: Power PC Sun: SPARC Compaq: Alpha T. K. Yin, NUK-CSIE • DRAM (dynamic random access memory) – A high-speed holding area for data and programs – Types • • • • SDRAM (synchronous DRAM) VCM (virtual channel memory) DRDRAM (direct rambus DRAM) DDR SDRAM (double data rate SDRAM) – Module • SIMM (single in-line memory module) • DIMM (double in-line memory module) T. K. Yin, NUK-CSIE VCM DRDRAM DDR SDRAM 200 PIN DDR333 256MB SO-DIMM T. K. Yin, NUK-CSIE • Cache memory – Level 1 cache: Built into the processor – Level 2 cache: On another chip, sitting between the processor and RAM • Volatile memory – DRAM – SRAM (static RAM): Used in cache memory • Nonvolatile memory – ROM (read only memory) • When you turn on a microcomputer system, aprogram in ROM automatically readies the computer for use and produces the initial display-screen prompt – PROM (programmable ROM) – Flash memory • The PC’s BIOS (basic input output system) is stored in flash memory T. K. Yin, NUK-CSIE • CMOS (complementary metal-oxide semiconductor ) – A type of memory chip with very low power requirements, and in PCs it operates using small batteries. In PCs, CMOS is more specifically referred to as CMOS RAM. – Store information your computer needs when it boots up, such as hard disk types, keyboard and display type, chip set, and even the time and date. T. K. Yin, NUK-CSIE T. K. Yin, NUK-CSIE • Buses and ports – The motherboard and its system bus must be linked to input, output, storage, and communication devices to receive data and return the results of processing – PCI local bus • The PCI local bus (peripheral component interconnect) enables circuit boards with extra features to be linked to the common system bus – AGP bus • The AGP bus (accelerated graphics port) is a special-function bus designed to accommodate the throughput demands of highresolution 3-D graphics T. K. Yin, NUK-CSIE – USB • The USB (universal serial bus) is the primary standard for connecting peripheral devices to a PC • The USB hub is a device connecting to a USB port and offering three, four, or five additional USB ports • USB 2.0 permits data transfer at 480 Mbps, about 40 times faster than the original USB standard – 1394 or FireWire bus • The 1394 bus supports data transfer rates of 400 Mbps for the original standard and 800 Mbps for the current standard – SCSI bus • The SCSI bus (small computer system interface) was an early alternative to using expansion slots to extend PC functionality • Up to 15 SCSI peripheral devices can be daisy-chained to a SCSI interface expansion card via the SCSI port T. K. Yin, NUK-CSIE – Serial port • The 9-pin or 25-pin RS-232C connector • An external modem might be connected to a serial port – Parallel port • Parallel ports use the same 25-pin RS-232C connector • Printers used parallel ports – IrDA port • The infrared port transmits data via infrared light waves T. K. Yin, NUK-CSIE USB connector 1394/FireWire connector T. K. Yin, NUK-CSIE PS/2 keyboard connector Ethernet connector SCSI cable Video/monitor cable Printer connector T. K. Yin, NUK-CSIE • Expansion boards – Graphic adapter • Normally an AGP board – Sound • Typically has receptacles for a microphone, a headset, an audio output and most has a port for a game controller and a MIDI (music instrument digital interface) port – – – – Data/voice/fax modem Network interface card SCSI interface card Video capture card T. K. Yin, NUK-CSIE Sound card Graphics adapter SCSI interface card Network interface card T. K. Yin, NUK-CSIE • PC cards – The PCMCIA card is a credit card-sized removable expansion module that is plugged into an external PCMCIA expansion slot on a PC, usually a notebook – Extended RAM, programmable nonvolatile flash memory, network interface cards (wireless and wired), data/voice/fax modems, hard-disk cards T. K. Yin, NUK-CSIE PCI card and PCMCIA radio card PCMCIA hard disk PCMCIA wireless network interface card PCMCIA flash memory T. K. Yin, NUK-CSIE • Processor description – Word size: bits handled as a unit • 32 bits • 64 bits – Core speed • PCs – MHz (millions of clock cycles per second) – GHz (billions of clock cycles per second) • PCs, workstations, server computers – MIPS (millions of instructions per second) • Supercomputers – FLOPS (floating point operations per second) T. K. Yin, NUK-CSIE – Bus speed • MHz • GHz • Memory capacity – – – – Kilobytes (KB): 1024 ( 210 ) bytes Megabytes (MB): 1,048,576 ( 2 20 ) bytes 30 Gigabytes (GB): 2 bytes Terabytes (TB): 2 40 bytes T. K. Yin, NUK-CSIE Storage Devices • Magnetic disk storage – Fixed disks • Hard disks – Interchangeable disks • Floppy disks: 1.44 MB • SuperDisk: 120 MB • Zip disks: 100, 250, 750 MB T. K. Yin, NUK-CSIE Floppy disk Hard disk Zip disk T. K. Yin, NUK-CSIE Superdisk • Optical laser discs – CD formats (650MB) • CD audio (compact disc): 4.72 inch • CD-ROM (compact disc-read-only memory) – 32X, 40X, 75X: Spin at 32, 40, and 75 times the speed of the original CD standard – Original 1X CD-ROM data transfer rate: 150 KB per second – Spin more quickly when accessing the data near the center (about 450 rpm) and more slowly for data near the edge (about 250 rpm) • CD-R (compact disc recordable) • CD-RW (CD-ReWritable) T. K. Yin, NUK-CSIE – DVD formats (4.7 GB or 9.4 GB for double sided) • DVD (digital video disc) audio, DVD video • DVD-ROM – The data transfer rate is nine times that of a CD-ROM spinning at the same rae • DVD+R, DVD-R: Like CD-R • DVD+RW, DVD-RW: Like CD-RW – DVD-RW (DVD-R) and DVD_RW (DVD+R) are competing technologies T. K. Yin, NUK-CSIE CD-R disc T. K. Yin, NUK-CSIE DVD-RW disc • Solid state storage – Flash memory • Mini USB drive T. K. Yin, NUK-CSIE Input Devices • Keyboard • Mouse • Point-and-draw devices – Trackpad: Common on notebook PCs – Trackpoint: Usually positioned in or near a notebook’s keyboard – Trackball: A ball inset in a notebook PC or as a separate unit – Joystick – Digitizer tablet and pen T. K. Yin, NUK-CSIE Keyboard Trackpad T. K. Yin, NUK-CSIE Mouse Trackpoint Trackball T. K. Yin, NUK-CSIE Joystick Digitizer tablet and pen • Scanner – Handheld label scanner • Read data on price tags, shipping labels, inventory part numbers, book ISBNs • Sometimes called wand scanners – Stationary label scanner • Applications like wand scanners • Common in grocery stored and discount stores – Document scanner • Scans documents of varying sizes • Read envelopes at the U.S. Postal Service, and also read turnaround documents for utility companies T. K. Yin, NUK-CSIE Stationary label scanner Handheld label scanner T. K. Yin, NUK-CSIE Document scanner • Image scanner – Page image scanner • The scanned result is a high-resolution digitized image – Hand image scanner • Rolled manually over the image to be scanned • Badge reader (for magnetic stripes and smart cards) – The magnetic stripes on the back of charge cards and badges offer another means of data entry • Speech recognition – Consists of software, a generic vocabulary database, and a high-quality microphone with noise-canceling capabilities T. K. Yin, NUK-CSIE Hand image scanner Page image scanner Badge reader T. K. Yin, NUK-CSIE Speech recognition • Digital camera • Desktop digital video camera – Webcam • Digital video cameras that are continuously linked to the Internet – Real-time Internet-based videophone conversations • Digital camcorder T. K. Yin, NUK-CSIE Webcam Digital camera T. K. Yin, NUK-CSIE Digital camcorder Output Devices • Monitors – CRT – Flat-panel • LCD (liquid crystal display): Active matrix or passive matrix • TFT (thin film transistor) LCD: Active matrix – Touch screen • Has pressure-sensitive overlays that can detect pressure and the exact location of that pressure T. K. Yin, NUK-CSIE – Monitor resolution • The number of pixels that can be displayed – 1024*768 • The number of bits used to represent each pixel – 8-bit color mode: 256 colors – 16-bit high-color mode: 65,536 colors – True color, either 24-bit or 32-bit mode • The dot pitch of the monitor – Dot pitch: The distance between the centers of adjacent pixels – .28 mm, .25 mm T. K. Yin, NUK-CSIE CRT monitor T. K. Yin, NUK-CSIE TFT LCD monitor Touch screen monitor • LCD projector • Printer – Laser • Nonimpact • 600 dpi (dots per inch), 1200 dpi – Ink-jet • Nonimpact • The droplets, ehich dry instantly as dots, form the letters and images – Large-format ink-jet, or plotter – All-in-one multifunction device: Print, fax, scan, and copy T. K. Yin, NUK-CSIE LCD projector Ink-jet printer Large-format ink-jet printer T. K. Yin, NUK-CSIE Laser printer Multifunction device • Sound System – Small speaker – 6.1 sound system • Voice-response system – Recorded voice – Speech synthesis T. K. Yin, NUK-CSIE References • Computers – Larry Long & Nancy Long, Twelfth Edition, Pearson Education, Inc • Invitation to Computer Science, C++ Version – G. Michael Schneider & Judith L. Gersting, Third Edition, Course Technology • Computer History Museum – http://www.computerhistory.org • http://archive.computerhistory.org/ T. K. Yin, NUK-CSIE