ch4- presentation
TRANSCRIPT
Computers
Chapter 4Inside the Computer
© 2005 Prentice-Hall, Inc. Slide 2
ComputersInside the Computer
Digital signals: Data is represented by a stream of bits.
Bit – short for binary digit (either 0 or 1)1 represents on0 represents off
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ComputersInside the Computer
The Language of ComputersEncoding systems
ASCII – American Standard Code for Information Interchange ANSI – American National Standards Institute UNICODE – capable of handling most printed languages
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ComputersInside the Computer
Digital: The Language of Computers Byte – collection of bits that represent a character
ASCII – 7 bits/byte ANSI – 8 bits/byte UNICODE – 16 bits/byte
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ComputersInside the Computer
The PC System Unit Connected to the Motherboard:
ProcessorChipsetMemory chipsExpansion boards
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ComputersInside the Computer
The PC System Unit Motherboard
System bus – permits communication between componentsDevice controllers – control peripheral devices
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ComputersInside the Computer
The PC System Unit The Processor: Computer on a Chip
Pentium 4CeleronXeonTM
ItaniumTM
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ComputersInside the Computer
CPU Speed: GHz, MIPS, and FLOPSGigahertz (GHz) – billions of clock cycles per second (Instructions)Megahertz (MHz) – millions of clock cycles per second (Instructions)
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ComputersInside the Computer
CPU Speed: GHz, MIPS, and FLOPSMIPS – millions of instructions per secondFLOPS – floating point operations per second; used to measure speed of supercomputers
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ComputersInside the Computer
RAM: (Temporary Memory) High-speed holding area for data and programs Volatile memory – data is lost if electrical current is not maintained
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ComputersInside the Computer
RAM: (Temporary Memory) DDR SDRAM – synchronous dynamic RAM SIMMs – single in-line memory modules DIMMs – dual in-line memory modules
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ComputersInside the Computer
CacheCache Memory – faster than RAMHoused on (L1) or near (L2) the CPU
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ComputersInside the Computer
Other High-Speed Memories ROM (read-only memory) – contains instructions to the computer that the user cannot change PROM (programmable ROM) – user can store read-only programs and data
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ComputersInside the Computer
Other High-Speed Memories Flash Memory
Nonvolatile memory – does not lose data in a power outage Easily upgraded BIOS (Basic Input Output System) – stored in flash memory
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ComputersInside the Computer
Memory CapacityMB (megabyte) – approximately 1 million bytesGB (gigabyte) – approximately 1 billion bytesTB (terabyte) – approximately 1 trillion bytes
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ComputersInside the Computer
Memory CapacityKB (kilobytes) – approximately 1000 bytesKb (kilobit)Mb (megabit)
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ComputersInside the Computer
Buses and PortsPCI (peripheral component interconnect) local bus – allows for circuit boards to connect to the common system bus
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ComputersInside the Computer
Buses and PortsExpansion slots – where expansion boards are installedExpansion boards or expansion cards – provide additional capabilities to the computer
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ComputersInside the Computer
Buses and PortsAGP (accelerated graphics port) bus– speeds up high-resolution 3-D graphics
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ComputersInside the Computer
Buses and PortsUSB (universal serial bus) – used to connect peripheral devices to the PCUSB hub – connects to the USB port and provides additional places to plug USB devices
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ComputersInside the Computer
Buses and PortsHot plug – USB devices can be attached or removed while the PC is runningUSB 2.0 – about 40 times faster than original USB
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ComputersInside the Computer
Buses and Ports1394 bus – similar to USB in speedFireWire – Apple terminologySupports hot plugging
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ComputersInside the Computer
Buses and PortsSCSI (small computer system interface) or “scuzzy” bus – early alternative to expansion slots in PCs
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ComputersInside the Computer
Legacy and Other PC PortsSerial port – data flows one bit at a timeParallel port – data flows several bits at a timeIrDA port or infrared port – data sent by light waves
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ComputersInside the Computer
Bus SpeedMost buses operate at MHzMajor block to efficiency in a PC
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ComputersInside the Computer
PC Growth: Adding CapabilitiesExpansion Boards – placed in expansion slots
Graphics adapterSound Data/voice/fax modemNetwork interface card (NIC)SCSI interface cardVideo capture card
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ComputersInside the Computer
PC Cards: PCMCIA TechnologyPCMCIA card or PC cardUsually used on notebook computers
Expand RAMNICHard-disk cardsGPS (global positioning system)
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ComputersChapter 5
• Storage Devices: (Permanente Storage) measured in Mega Bytes (MB), or Gaga Bytes (GB)– Hard Drive– Floppy Disc– CD-ROM– DVD-ROM– CD-R (Recordable)– CD-RW (Rewritable)– DVD-R, DVD+R– DVD-RW, DVD+RW– DVD+,-RW
ComputersInside the Computer
Build Your Own PCAdvantages
Cheaper (for high-end systems)Meets your requirements
DisadvantagesNo warranty on systemNo help desk
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