Introduction to Computer Science (I)

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Introduction to Computer Science (I)

• Inside the Computer

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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

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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

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• Digitalized data in computers
• Letters
• Numbers
• Colors
• Sounds
• Images
• Odors
• Bit An on or off electronic state
• On-bit 1
• Off-bit 0

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• On and off states inside the computers
• RAM Presence or absence of an electrical charge
  in an integrated circuit

Source http//www.intel.com/research/silicon/nano
technology.htm
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• 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
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• CD and DVD Digital data are stored permanently
  as microscopic pits

Source http//www.opticaldisc-systems.com/2002Sep
Oct/DVDBASICS80.htm
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• Fiber optic cable Binary data are pulses of
  light
• Electrical transmission media Binary numbers are
  electrical signals

Source http//www.bsu.edu/web/CBTHORNBERRY/trends
5.html
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• 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

Source http//www.unicode.org/charts/PDF/U0000.pd
f
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• Unicode A 16-bit encoding system to represent
  more characters than the English language

Source http//www.unicode.org/charts/PDF/U4E00.pd
f
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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

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• Include four major subsystems called memory,
  input/output, the arithmetic/logic unit (ALU),
  and the control unit

Memory
Memory
Control unit
ALU
Processor
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• 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
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• The major devices of a personal computer
• The PC system unit
• Storage devices
• Input devices
• Output devices

Storage Devices
System Unit
CPU
Output Devices
Input Devices
Control Unit
ALU
Main Memory
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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

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1 Processor socket 2 DIMM sockets 3. Floppy
connector 4 Hard disk connectors 5 Chipset 6
PCI expansion slots 7 AGP video cord slot
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1
7
5
2
3
4
Source http//www.asus.com
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1 PS/2 mouse port 2 Parallel port 3 RJ-45
port 4 Line In port 5 Line Out port 6
Microphone port
7 USB 2.0 ports 1 and 2 8 VGA por 9 S/PDIF out
port (digital audio) 10 USB 2.0 ports 3 and
4 11 PS/2 keyboard port
Source http//www.asus.com
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• 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

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• 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)

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VCM
DRDRAM
DDR SDRAM 200 PIN DDR333 256MB SO-DIMM
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• 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 PCs BIOS (basic input output system) is
  stored in flash memory

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• 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.

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• 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 high-resolution 3-D graphics

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• 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

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• 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

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PS/2 keyboard connector
USB connector
Ethernet connector
1394/FireWire connector
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SCSI cable
Video/monitor cable
Printer connector
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• 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

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Sound card
Graphics adapter
SCSI interface card
Network interface card
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• 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

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PCI card and PCMCIA radio card
PCMCIA hard disk
PCMCIA wireless network interface card
PCMCIA flash memory
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• 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)

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• Bus speed
• MHz
• GHz
• Memory capacity
• Kilobytes (KB) 1024 ( ) bytes
• Megabytes (MB) 1,048,576 ( ) bytes
• Gigabytes (GB) bytes
• Terabytes (TB) bytes

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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

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Floppy disk
Hard disk
Zip disk
Superdisk
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• 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)

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• 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
• DVDR, DVD-R Like CD-R
• DVDRW, DVD-RW Like CD-RW
• DVD-RW (DVD-R) and DVD_RW (DVDR) are competing
  technologies

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CD-R disc
DVD-RW disc
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• Solid state storage
• Flash memory
• Mini USB drive

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Input Devices

• Keyboard
• Mouse
• Point-and-draw devices
• Trackpad Common on notebook PCs
• Trackpoint Usually positioned in or near a
  notebooks keyboard
• Trackball A ball inset in a notebook PC or as a
  separate unit
• Joystick
• Digitizer tablet and pen

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Keyboard
Mouse
Trackpad
Trackpoint
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Joystick
Trackball
Digitizer tablet and pen
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• 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

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Stationary label scanner
Handheld label scanner
Document scanner
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• 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

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Hand image scanner
Page image scanner
Badge reader
Speech recognition
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• 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

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Webcam
Digital camera
Digital camcorder
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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

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• Monitor resolution
• The number of pixels that can be displayed
• 1024768
• 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

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CRT monitor
TFT LCD monitor
Touch screen monitor
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• 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

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LCD projector
Ink-jet printer
Laser printer
Large-format ink-jet printer
Multifunction device
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• Sound System
• Small speaker
• 6.1 sound system
• Voice-response system
• Recorded voice
• Speech synthesis

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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/