How Computers Work

1
How Computers Work

• Chapter 1

2
Hardware Needs Software to Work

• Hardware computers physical devices
• Monitor, keyboard, memory chips, hard drive
• Software instructions that directs the hardware
  to perform a task.

3
Hardware Needs Software to Work

• Software uses hardware for 4 basic things
• Input
• Processing
• Output
• Storage
• See figure 1-1 pg. 2

4
Hardware Needs Software to Work

• Hardware components also communicate data and
  instructions among themselves.
• Must have electrical power system.

5
User Interaction with Computer

• Software must convert instructions given by the
  user into a language the computer understands.
• The computer understands two things
• Yes which means ON
• No which means OFF
• Figure 1-2 pg. 3

6
Binary Number System

• 1940 John Atanasoff can up with the idea to
  store and read only two values in a computer
  system, ON and OFF.
• Either there was a charge , ON, or there wasnt a
  charge, OFF.
• We use the numbers 1 and 0 to represent ON and
  OFF binary number system.

7
Binary Numbering System

• A 1 or 0 is called a bit.
• Also called a binary digit.
• Bits are generally group in groups of 8.
• 8 bits make up a byte.

8
Counting Binary Numbers

• All counting and calculations use the binary
  number system.
• Counting goes as followed
• 0, 1, 10, 11, 100, 101..
• All letters and numbers must be converted to
  binary code before being stored.
• Letter A 0100 0001
• Number 25 0001 1001
• Figure 1-3 pg. 4

9
PC Hardware Components

• Chapter 1

10
Hardware Components

• Most input/output devices are located outside the
  case.
• Most processing and storage devices are found in
  the case.
• The CPU is the most important device in the case.

11
Microprocessor (CPU)

• Central to all processing done by the computer.
• Data received by the input devices is read by the
  CPU.
• Output from the CPU is written to output devices.

12
PC Hardware Components

• Each input, output, and processing component
  requires these elements to operate
• A method for the CPU to communicate with the
  device.
• Software to instruct and control the device.
• Electricity to power the device.

13
A method for the CPU to communicate with the
device

• Data must be either sent to the CPU or received
  from the CPU.

14
Software to instruct and control the device

• Hardware devices cannot work without software to
  run it.
• The software must have access to the CPU in order
  run the device.
• Each device responds to specific instructions
  based on the function of the device.

15
Electricity to power the device

• Electronic devices need electricity to run the
  device.
• All computers need to have a power supply to run.
• Usually an electrical outlet.

16
Hardware Input and Output

• Input/output devices are used to communicate with
  devices inside the computer.
• Accomplished by either cables, which attach to a
  connection called a port, or by a wireless
  connection.
• Most ports are found in the back of the computer.
• Figure 1-4 pg. 5

17
Input devices

• Keyboard primary input device.
• Standard keyboard has 104 keys.
• Mouse a pointing device used to move a pointer
  on the screen and to make selections.
• Can have 1, 2, or 3 buttons.
• Both a mouse and keyboard can have 6 pin
  connector (figure 1-5) or a USB connector.

18
Output devices

• Monitor visual device that displays the primary
  output of the computer.
• Rated by the monitors resolution, which is the
  number of dots used to display.
• Printer produces output on paper called a
  hardcopy.
• Most printers are either an ink-jet, laser, and
  solid ink.

19
Hardware inside the computer
20
Hardware inside the computer

• Most computers can have these devices
• Motherboard containing the CPU, memory, and other
  components.
• Hard drive, DVD and CD-ROM.
• A power supply supplying electricity.
• Circuit boards used by the CPU to communicate to
  other devices.
• Cables connecting devices to circuit boards and
  the motherboard.
• Figure 1-7 pg. 8

21
Circuit boards

• A board that holds microchips, integrated
  circuits (ICs), and the circuitry that connects
  these chips.
• Expansion Cards circuit boards that are
  installed in long narrow expansion slots on the
  mother board.
• Expansion slots Open slots used to additional
  components.

22
Circuit boards

• CMOS chips (complementary metal-oxide
  semiconductor)
• All circuit boards contain microchips which are
  manufactured using CMOS.
• Require less electricity and produce less heat.

23
Other components

• The other main components inside the computer
  look like small boxes, like the power supply,
  floppy drive, hard drive, and CD-ROM.

24
Cables

• Two types of cables are found inside the
  computer
• Data cables connect devices to one another.
• Flat and wide cables
• Power cables supply power.
• Round and small cables

25
The motherboard
26
The motherboard

• The largest and most important circuit board.
• Also called the system board and main board.
• Contains the CPU.
• Because of the complexity and importance of the
  CPU, all devices are either installed on the
  mother board or connect to it.

27
The motherboard

• Devices that are not on the motherboard is called
  a peripheral device.
• Some ports stick outside the case to connect to
  external devices.
• Figure 1-8 pg. 9

28
The mother board

• Serial ports named because data is transferred
  serially (one bit follows the next).
• Parallel ports transmits data in parallel and
  is most commonly used by a printer.
• Universal Serial Bus ports (USB) used by a
  number of input/output devices.
• 1394 port used by high speed multimedia devices
  such as digital camcorders.
• Figure 1-9 pg. 10

29
Items found on the motherboard

• Processing components
• CPU most important chip.
• Chip set controls motherboard activities
• Temporary storage
• Random Access Memory (RAM) holds data and
  instructions as they are processed.
• Cache memory speed ups memory access.

30
Items found on the motherboard

• Components that communicate with the CPU with
  other devices.
• Traces wires on the motherboard used for
  communication.
• Expansion slots connect expansion cards to the
  motherboard.
• System clock keeps communication in sync.
• Electrical system
• Provide power to the motherboard and expansion
  cards.

31
Items found on the motherboard

• Programming and setup data
• Flash ROM a memory chip used to permanently
  store instructions that control hardware
  functions.
• CMOS chip holds configuration data.

32
The CPU and the Chip Set

• The CPU could not do its job without the
  assistance of the chipset.
• Chipset group of microchips on the motherboard
  that control the flow of data and instructions to
  and from the CPU.
• Figure 1-10 pg. 11
• Figure 1-11 pg. 12

33
Storage Devices

• 2 types of storage
• Temporary and Permanent
• CPU uses temporary storage called primary storage
  or memory.
• Primary storage is much faster to access than
  permanent memory.

34
Storage Devices

• When data and instructions are not being used,
  they are stored in permanent storage called
  secondary storage.
• Floppy disk, hard drive
• Figure 1-12 pg. 13

35
Primary Storage

• Primary storage is provided by devices called RAM
• Random Access Memory
• Located on the motherboard and other circuit
  boards
• RAM chips are installed directly on a small board
  on the motherboard or in banks that plug into the
  motherboard.
• Figure 1-13 pg. 14

36
Primary Storage

• The most common types of boards that hold memory
  are
• Single Inline Memory Modules (SIMM)
• Dual Inline Memory Modules (DIMM)
• Rambus Inline Memory Modules (RIMM)
• Memory in RAM is lost when the computer is shut
  off.
• They need a continuous supply of electricity.

37
Primary Storage

• Because RAM always needs electricity, it is
  referred to as volatile memory.
• However, there is nonvolatile memory called ROM
  (Read Only Memory).
• Holds data even when no electricity is present.
• Figure 1-14 pg. 14

38
Secondary Storage

• Data that is stored on devices such as CDs,
  disks, hard drives, and so on.
• Data and instructions can not be processed from
  these locations.
• It must first be copied to Primary Storage.
• IMPORTANT secondary memory is PERMANENT memory.

39
Secondary Storage

• Hard drive a sealed case containing platters
  and disks that rotate at a high speed.
• Figure 1-16 pg. 16
• As platters rotate, an arm reaches across the
  platters, both writing new data and reading
  existing data.

40
Hard drives

• Hard drives use a technology called
• Integrated Drive Electronics (IDE)
• IDE provides two connectors on a motherboard for
  two data cables.
• Figure 1-17 pg. 17
• Figure 1-18 pg. 17
• A motherboard can accommodate up to 4 IDEs
• Hard drives, ZIP drives, CD-ROMs all use these
  IDE connections.

41
Hard drive

• Receives its power from the power supply by way
  of a power cord.
• Figure 1-19 pg. 18

42
Other Secondary Storage Devices

• Floppy Drive
• Holds up to 1.44 MB of data
• CD-ROM Drive
• Most software is distributed by CD-ROM

43
Motherboard Components use for Communication
Among Devices

• Traces circuits (paths) that enable data,
  instructions and power to transfer from component
  to component.
• This system of pathways used for communication
  and the protocol and methods used for
  transmission are called the bus.

44
Motherboard Components use for Communication
Among Devices

• Protocol set of rules and standards that any
  two entities use for communication.
• Data bus paths, or lines of the bus that are
  used to move data.
• Figure 1-24 pg. 21

45
Motherboard Components use for Communication
Among Devices

• Binary data is put on a line of a bus by placing
  voltage on that line.
• This voltage is traveling on top of the line, not
  on it.

46
Transferring data between components

• When one component at one end of the line wants
  to write data to another component, the two must
  get in sync for the write operation.
• The first component places voltage on several
  lines of the bus, and the other component
  immediately reads the voltage on those lines.

47
Transferring data between components

• The CPU interprets the voltage on each line as
  binary digits.
• Some buses have data paths that are 8, 16, 32,
  64, or 128 bits wide.
• If a bus has 8 wires to transmit data, it is
  called an 8 bit bus.
• Remember There are only two states inside a
  computer. On or Off.
• If there is a voltage, then it is represented by
  a 1, and just the opposite if there is no
  voltage.
• Figure 1-25 pg. 22

48
Bus

• Data Path Size width of a data bus.
• There can be multiples buses on a motherboard.
• The main bus on the motherboard has several
  different names
• System bus
• Memory bus
• Host bus
• Local bus
• Front Side bus (FSB)

49
System clock

• System clock circuit dedicated to timing the
  activities of the chips on the motherboard.
• Figure 1-26 pg. 23
• Clock speed the number of beats which are
  measured in Hertz (Hz)
• Hertz one cycle per second.
• Megahertz (MHz) one million cycles per second.
• Gigahertz (GHz) one billion cycles per second.

50
Transferring data between components

• The lines of a bus often expand to expansion
  slots.
• Figure 1-27 pg. 24
• The kind of bus you depends on the type of
  expansion slot.

51
Expansion slots

• 3 general types of expansion slots
• PCI (Peripheral Component Interconnect)
• Slot used for high-speed I/O devices
• AGP (Accelerated Graphics Port)
• Slot used for a video card
• ISA (Industry Standard Architecture)
• Slot used for older or slower devices
• Figure 1-27 pg. 24Figure 1-28 pg. 24

52
Interface (Expansion) Cards

• Circuit boards, other than motherboards, are
  sometimes called circuit cards, adapter cards,
  expansion cards, and interface cards.
• Figure 1-30 pg. 25
• Figure 1-31 pg. 26

53
Interface (Expansion) Cards

• Video Card provides a port for the monitor to
  connect to.
• Sound Card provides ports for speakers and
  microphones.
• Network Card provides ports for a network cable
  to connect the PC to a network.

54
The Electrical System

• Most important component of the computers
  electrical system.
• Usually located near the back of the case.
• Power supply does not actually produce
  electricity.
• Converts it and reduces it to a voltage that the
  computer can handle.

55
Power Supply

• The power supply also runs a fan directly from
  the electrical output voltage to help cool the
  inside of the case.
• Temps over 185 degrees F. can cause damage.
• Every motherboard has one pair of connections to
  receive power from the power supply.
• Figure 1-32 on pg. 27
• Figure 1- 33 on pg. 28

56
Power Supply

• Power supply can receive up to 120 AC power.
• Newer power supplies will convert that into 3.3,
  5, and 12 volts of DC power.

57
Instructions stored on the Motherboard

• Basic instructions, which start the computer, are
  stored on the motherboard.
• This data is stored in ROM chips called BIOS.
• Basic Input-Output System
• Figure 1-34 pg. 29

58
Instructions stored on the Motherboard

• ROM BIOS serve 3 purposes
• The BIOS that is sometimes used to manage simple
  devices is called system BIOS.
• The BIOS that is used to start the computer is
  called startup BIOS.
• The BIOS that is used to change some settings on
  the motherboard is called CMOS setup.

59
Plug and Play

• PnP standard designed to make the installation
  of new hardware devices easier.
• The computer system BIOS will recognize the
  device, and will begin the configuration of the
  new device.