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

© 2005 Prentice-Hall, Inc. Slide 6

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

© 2005 Prentice-Hall, Inc. Slide 7

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

© 2005 Prentice-Hall, Inc. Slide 8

ComputersInside the Computer

The PC System Unit Connected to the Motherboard:

ProcessorChipsetMemory chipsExpansion boards

© 2005 Prentice-Hall, Inc. Slide 11

ComputersInside the Computer

The PC System Unit Motherboard

System bus – permits communication between componentsDevice controllers – control peripheral devices

© 2005 Prentice-Hall, Inc. Slide 12

ComputersInside the Computer

The PC System Unit The Processor: Computer on a Chip

Pentium 4CeleronXeonTM

ItaniumTM

© 2005 Prentice-Hall, Inc. Slide 13

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)

© 2005 Prentice-Hall, Inc. Slide 39

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

© 2005 Prentice-Hall, Inc. Slide 40

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

© 2005 Prentice-Hall, Inc. Slide 18

ComputersInside the Computer

RAM: (Temporary Memory) DDR SDRAM – synchronous dynamic RAM SIMMs – single in-line memory modules DIMMs – dual in-line memory modules

© 2005 Prentice-Hall, Inc. Slide 19

ComputersInside the Computer

CacheCache Memory – faster than RAMHoused on (L1) or near (L2) the CPU

© 2005 Prentice-Hall, Inc. Slide 20

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

© 2005 Prentice-Hall, Inc. Slide 21

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

© 2005 Prentice-Hall, Inc. Slide 22

ComputersInside the Computer

Memory CapacityMB (megabyte) – approximately 1 million bytesGB (gigabyte) – approximately 1 billion bytesTB (terabyte) – approximately 1 trillion bytes

© 2005 Prentice-Hall, Inc. Slide 42

ComputersInside the Computer

Memory CapacityKB (kilobytes) – approximately 1000 bytesKb (kilobit)Mb (megabit)

© 2005 Prentice-Hall, Inc. Slide 43

ComputersInside the Computer

Buses and PortsPCI (peripheral component interconnect) local bus – allows for circuit boards to connect to the common system bus

© 2005 Prentice-Hall, Inc. Slide 27

ComputersInside the Computer

Buses and PortsExpansion slots – where expansion boards are installedExpansion boards or expansion cards – provide additional capabilities to the computer

© 2005 Prentice-Hall, Inc. Slide 28

ComputersInside the Computer

Buses and PortsAGP (accelerated graphics port) bus– speeds up high-resolution 3-D graphics

© 2005 Prentice-Hall, Inc. Slide 29

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

© 2005 Prentice-Hall, Inc. Slide 30

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

© 2005 Prentice-Hall, Inc. Slide 31

ComputersInside the Computer

Buses and Ports1394 bus – similar to USB in speedFireWire – Apple terminologySupports hot plugging

© 2005 Prentice-Hall, Inc. Slide 32

ComputersInside the Computer

Buses and PortsSCSI (small computer system interface) or “scuzzy” bus – early alternative to expansion slots in PCs

© 2005 Prentice-Hall, Inc. Slide 33

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

© 2005 Prentice-Hall, Inc. Slide 34

ComputersInside the Computer

Bus SpeedMost buses operate at MHzMajor block to efficiency in a PC

© 2005 Prentice-Hall, Inc. Slide 41

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

© 2005 Prentice-Hall, Inc. Slide 35

ComputersInside the Computer

PC Cards: PCMCIA TechnologyPCMCIA card or PC cardUsually used on notebook computers

Expand RAMNICHard-disk cardsGPS (global positioning system)

© 2005 Prentice-Hall, Inc. Slide 36

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

© 2005 Prentice-Hall, Inc. Slide 37