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Module 5 Hardware.

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Presentation on theme: "Module 5 Hardware."— Presentation transcript:

1 Module 5 Hardware

2 What Computers Do Process Information Produce Output Receive Input
Store Information

3 4 Primary Components of a Computer
Secondary - hard disks - removable disks - CDs - tapes Primary - memory - RAM - ROM Storage Devices Input Devices Processing Output Devices - keyboard - mouse - scanner - digital camera - touchpad CPU Control Unit Arithmetic & Logic Unit - monitor - printer - speakers

4 Processing - CPU “Central Processing Unit”
evolution of processors the “brains” of the computer, where calculations take place two parts: ALU - Arithmetic Logic Unit electronic circuitry that does all arithmetic and logic operations Control Unit circuitry that directs all other parts of the computer

5 Input Devices accept input from the outside world.
most common is the keyboard, followed by the mouse sends signals to the computer, telling it what you’ve “told” it

6 Output Devices sends output to the outside world
converts and displays the computer’s internal bit patterns to a format that humans can understand Main output devices are monitors for immediate visual output printers for permanent paper output

7 Screen Output A monitor or video display terminal (VDT) displays characters, graphics, photographic images, animation and video. Video adapter —connects the monitor to the computer VRAM or video memory—a special portion of RAM to hold video images (the more video memory, the more detail of a picture displayed)

8 Screen Talk Monitor size - measured as a diagonal line across the screen. Pixels (or picture element) - tiny dots that compose a picture Resolution - the number of pixels displayed on the screen (the higher the resolution, the closer together the dots)

9 Image Quality Image quality is affected by resolution and color depth (or bit depth) Color depth refers to the number of different colors a monitor displays at the same time

10 Examples of Color Depth
1-bit depth 16-bit depth 8-bit depth 4-bit depth

11 Paper Output Printers produce paper output or hard copy
2 kinds of printers: Impact printers Non-impact printers

12 Impact Printers Line printer Dot matrix printer
Used by mainframes to produce massive printouts Limited to printing characters Dot matrix printer Images created by a matrix of tiny dots Low print quality Low cost

13 Non-impact Printers Laser Printer
A laser beam reflected off a rotating drum to create patterns of electrical charges Faster and more expensive than dot matrix printer High-resolution output

14 More on Non-impact Printers
Ink-jet Printer Sprays ink onto paper to produce printed text and graphic images Prints fewer pages/minute than laser printer High-quality color costing less than laser printer

15 Storage devices

16 Storage/Memory Devices
Divided into two groups: Primary storage usually a temporary storage for the data and programs currently in operation or currently being accessed. it’s fastest and most expensive Secondary storage long-term storage locations cheap but slower than primary memory some are portable/removable larger capacity than primary memory

17 Primary Storage - RAM RAM: Random Access Memory
very fast - access times < 1 billionth of a second – in nanoseconds volatile storage - once the computer is turned off, everything is lost this is where data and programs currently being used reside a document that has not yet been “saved” is in RAM and will be lost if the computer freezes or the power goes off

18 Primary Storage - ROM ROM = Read Only Memory
permanent memory (doesn’t disappear if the computer is turned off) normally holds the data/programs needed to start (“boot up”) the computer typically, cannot be altered except by physically changing the chip RAM ROM

19 Secondary Storage Secondary storage devices are computer peripherals capable of performing both input and output functions Information is stored semi-permanently on tape and disk drives Examples of storage devices Magnetic tapes and disks Zip, Jaz and SuperDisks Optical disks

20 Secondary storage - Magnetic Tape
Magnetic tapes Sequential access Can store large amounts of information in a small space at a relatively low cost Limitation: sequential access Used mainly for backup purposes

21 Magnetic Media Magnetic drives Random access
Floppy disks for inexpensive, portable storage Hard disks are typically non-removable, rigid disks that spin continuously and rapidly thus providing much faster access than a floppy disk. Removable media (Zip & Jaz disks) provide high-capacity portable storage.

22 Hard Disk magnetic storage
data is saved until something is written over it (or it gets damaged somehow) data saved on “platters” and read with a “head” platters spin at RPM head can move to center and back to edge about 50 times per second platters divided into “tracks” and “sectors” to make it easier to retrieve data. picture from

23 Optical Media Optical disk drive uses laser beams to read and write bits of information on the disk surface. Not as fast as magnetic hard disks Massive storage capacity and reliability

24 Types of Optical Media CD-ROM drives are optical drives that read CD-ROMs. CD-R are WORM media (write-once, read many). Hold about 700megabytes of info CD-RW can read CD-ROMs and write (onto CD-R), erase and rewrite data onto CD-RW disks. DVD (digital video disks) store & distribute all kinds of data. They hold between 3.8 and 17 gigabytes of information.

25 Solid-state Storage Devices
Flash memory is an erasable memory chip. Compact alternative No moving parts Designed for specific applications such as storing pictures in digital cameras Likely to eventually replace disk and tape storage

26 Processing

27 Ron White, in How Computers Work
The CPU The microprocessor that makes up your personal computer’s central processing unit, or CPU, is the ultimate computer brain, messenger, ringmaster and boss. All the other components—RAM, disk drives, the monitor— exist only to bridge the gap between you and the processor. Ron White, in How Computers Work

28 The CPU The CPU: interprets and executes instructions
performs arithmetic and logical data manipulations communicates with the other parts of the computer system.

29 The CPU CPU The CPU is a complex collection of electronic circuits.
When all of those circuits are built into a single silicon chip, the chip is referred to as a microprocessor. The circuit board that contains a computer’s CPU is called the motherboard or system board. motherboard

30 CPU Speed A computer’s speed is determined in part by the speed of its internal clock The clock is a timing device that produces electrical pulses to synchronize the computer’s operations. A computer’s clock speed is measured in units called megahertz (MHz), for millions of clock cycles per second

31 CPU Speed Parallel processing places multiple processors in a computer. Most supercomputers have multiple processors that divide jobs into pieces and work in parallel on the pieces.

32 Ports and Slots Tying things together

33 Ports and Slots The system or motherboard includes several standard ports: Serial Port for attaching devices that send/receive messages one bit at a time (modems) Parallel Port for attaching devices that send/receive bits in groups (printers) Keyboard/Mouse Port for attaching a keyboard and a mouse

34 More on Ports and Slots Other ports are typically included on expansion boards rather than the system board: Video Port used to plug in a color monitor into the video board Microphone, speaker, headphone, MIDI ports used to attach sound equipment SCSI port allows several peripherals to be strung together and attached to a single port

35 Expansion Made Easy With the open architecture of the PC and the introduction of new interfaces, you can now hot swap devices. USB (Universal Serial Bus) transmits a hundred times faster than a PC serial port Firewire (IEEE 1394) can move data between devices at 400 or more megabits per second high speed makes it ideal for data-intensive work like digital video

36 Bits and Bytes

37 Information 1 2 3 Information comes in many forms
Numbers Text Sounds Pictures Computers store information in digital form

38 Bit Basics A bit (binary digit) On/off
is the smallest unit of information can have two values: 1 or 0 can represent numbers, codes, or instructions On/off

39 Bits as Numbers Each switch can be used to store a tiny amount of information, such as: An answer to a yes/no question A signal to turn on a light Larger chunks of information are stored by grouping bits as units 8 bits (byte) = 256 different messages

40 Bits As Codes ASCII – American Standard Code for Information Interchange Most widely used code, represents each character as a unique 8-bit code.

41 Bits as Instruction The computer stores instructions as collections of bits. For instance, might instruct the computer to add two numbers. Other bit instructions might include where to find numbers stored in memory or where to store them.

42 Bits, Bytes, and Buzzwords
Terms used to describe file size or memory size: Byte Kilobyte (KB) Megabytes (MB) Gigabytes (GB) Terabytes (TB) = 8 bits ≈ 1 Thousand Bytes ≈ 1 Million Bytes ≈ 1 Billion Bytes ≈ 1 Trillion Bytes

43 The logic machine How do we build a computer that doesn’t need to be rewired each time we want to perform a different task? Connect the components in such a way that the program itself controls the “rewiring” by signaling the hardware to switch the components on and off in the proper sequence

44 Logic Gates Using switches, we can reproduce the logical operators
AND OR NOT 0 = false = off 1 = true = on

45 AND is written like a multiply
Q PQ 1

46 OR OR is written like an addition P Q P+Q 1

47 NOT is written with an ’ after the letter
P P’ 1

48 “if both P and Q are the same, then the result is true”
Simple Truth Table “if both P and Q are the same, then the result is true” P Q PQ + P’Q’ (result) 1

49 Example: check to see if P and Q are equal
Step 1: build Truth Table The truth table for “P and Q are equal” looks like: P Q Result 1 P = 0, Q = 0 they are equal so result is true (1) P = 1, Q = 1 they are equal, so result is true (1)

50 the ’ means NOT… so P’ means that P is off/0
Step 2: Build an AND statement for each line where Result = 1 the ’ means NOT… so P’ means that P is off/0 P Q Result 1 P’ AND Q’ = P’Q’ P AND Q = PQ

51 Step 3: result = P’Q’ + PQ Join each line with OR-statements P’Q’ PQ

52 Example 2: P’Q’ PQ’ PQ P Q S 1
Step 1: Build Truth Table … already done for us P Q S 1 P’Q’ PQ’ PQ Step 2: Build equation terms using ANDs

53 P’Q’ PQ’ PQ S = P’Q’ + PQ’ + PQ P Q S 1
1 P’Q’ PQ’ PQ Step 3: Build equation by joining terms from step 2 with ORs S = P’Q’ + PQ’ + PQ

54 Drawing circuits

55 Gates AND = * = OR = + = NOT = ’ = One output Two inputs Two inputs
One input

56 Gates to switches Logical gates can be converted to physical switches that operate exactly as expected We can combine gates to act like our statements from the truth tables since we have a gate for each of AND, OR, NOT

57 Building Circuits We build the circuit in the exact same order as we build the equation figure out the inputs do all the NOTs next all the ANDS lastly all the ORs

58 One input (light switch) for each letter in the equation
Example Result = PQ + P’Q’ Step A: Inputs P Q One input (light switch) for each letter in the equation

59 Result = PQ + P’Q’ P’ Q’ Step B: NOTs P P Q Q

60 Remember AND is the same as a multiply
Result = PQ + P’Q’ Remember AND is the same as a multiply P Q PQ P’ Q’ P’Q’ Step C: ANDs P Q

61 Remember OR is the same as addition
Result = PQ + P’Q’ PQ + P’Q’ Remember OR is the same as addition Step D: ORs PQ P Q P’Q’ The light will light up when the inputs are both the same, as described in the truth table

62 Example 3 inputs, light-up if exactly 2 inputs are true
Step 1: Build Truth Table X Y Z Result 1

63 result = X’YZ + XY’Z + XYZ’
Step 2: build terms with ANDs (where result is true) X Y Z Result 1 X’YZ XY’Z XYZ’ Step 3: Build equation by joining terms with ORs result = X’YZ + XY’Z + XYZ’

64 result = X’YZ + XY’Z + XYZ’
Step 4: Build circuit result = X’YZ + XY’Z + XYZ’ Step A: Inputs X Y Z

65 result = X’YZ + XY’Z + XYZ’
Step B: NOTs X Y Z

66 result = X’YZ + XY’Z + XYZ’
Step C: ANDs X Y Z

67 result = X’YZ + XY’Z + XYZ’

68 result = X’YZ + XY’Z + XYZ’

69 Using Loggo to combine gates
Go to the class homepage and look for the Loggo applet in the Miscellaneous section Try implementing different equations to see if they match the truth tables

70 Corresponding Readings
Chapter 2 Chapter 3

71 To Know – Module 5 Vocabulary/definitions Truth tables / circuits
From a description, write truth table From truth table, write equation From equation, build circuit


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