Introduction to hardware

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# Introduction to hardware - PowerPoint PPT Presentation

Concepts covered Units of measurement Processors Memory Input and output Storage Peripherals. Introduction to hardware. Byte 8 bits. Basic units of measurement. Bit bi nary digi t smallest unit of measurement two possible values. Word

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Presentation Transcript

Concepts covered

• Units of measurement
• Processors
• Memory
• Input and output
• Storage
• Peripherals

### Introduction to hardware

Byte

• 8 bits
Basic units of measurement
• Bit
• binary digit
• smallest unit of measurement
• two possible values
• Word
• The number of adjacent bits that can be stored and manipulated as a unit
• 32, 64 for home computers, 128 for the most powerful
Large units of measurement (storage size)
• Note: use powers of two because computer storage (bytes) are based on the basic unit (bit).

Kilobyte (kB) – a thousand bytes (1,024 = 210)

Megabyte (MB) - a million (1,048,576 = 220)

Gigabyte (GB) – a billion (1,073,741,824 = 230)

Terabyte (TB) – a trillion (1,099,511,627,776 = 240)

~ 20 million four-drawer filing cabinets full of text

Petabyte (PB) – a quadrillion (1.125899906843e+15 = 250)

Small units of measurement (speed)
• millisecond (ms) – a thousandth of a second (1/1,000 = 10-3)

microsecond (μs) - a millionth of a second (1/1,000,000 = 10-6)

nanosecond (ns) – a billionth of a second (1/1,000,000,000 = 10-9)

What is hardware?
• Hardware includes the physical components of a computer system e.g., a monitor, keyboard, mouse and the computer itself.

A real processor

Processor

(maybe not…)

• The brains of a computer
Processor speed
• Determined by many things
• Type of processor
• Clock speed (as measured in Hertz e.g., MHz, GHz)
• * But also consider the rest of the computer!
Relationship between clock speed and times between pulses
• Examples
• 1 Hz = 1 pulse is sent out each second (1 second passes between each pulse)
• 10 Hz = 10 pulses are sent out each second (0.1 seconds passes between each pulse)
• :
• 25 MHz machine = 25 million pulses sent out each second (0.000 000 04 seconds between each pulse or 40 ns between pulses)
Some common types of processors
• Intel processors (usually run some version of MS-Windows)
• Type of processor Clock speed
• Celeron 500 MHz – 1.3 GHz
• Pentium III 650 MHz – 1.2 GHz (1200 MHz)
• Pentium IV 1.4 GHz (1400 MHz) – 2.2 GHz (2200 MHz)
• PowerPC processors in Apple computers
• Type of processor Clock speed
• G3 500 MHz – 700 MHz
• G4 733 MHz or 867 MHz
CISC processors and RISC processors
• CISC (Complex Instruction Set Computers
• e.g., Pentium; 68000, 68020…(old Apple computers)
• RISC (Reduced Instruction Set Computers)
• e.g., PowerPC (new Apple computers)
• Difference
• Instructions on RISC computers are simpler?
• Architecture differs between the processors.
Types of memory
• 1) RAM
• 2) ROM
• 3) Caches
1) RAM (Random access memory)
• Often used for short term storage of information
Characteristics of RAM
• Volatile
• Used for temporary storage
• Typical ranges 128 MB ~1 GB
• You can read but not change the contents
• Contents written to (burnt) by special equipment
• Non-volatile
Types of ROM
• ROM
• PROM
• EPROM
• EEPROM
• Flash Memory (e.g., a computer BIOS, memory for game consoles)
3) Cache memory
• Stores less than RAM but much faster
• Can be either part of the processor (L1) or separate from it (L2)
• Both are much faster than regular memory RAM
Input devices
• Used by a person to communicate to a computer.

Person to computer

Output devices
• Displays information from the computer to the a person.

Computer to a person

Most common output device
• A computer monitor
How many monitors work
• Images are displayed with dots (pixels)

Picture from Beekman

Quality of monitors determined by
• Size
• Resolution
• Color depth
• Dot pitch
1) Monitor quality (size)

Measured diagonally

2) Monitor quality (resolution)
• Columns of pixels x Rows of pixels
3) Monitor quality (Color depth)
• The number of possible colors that can be displayed for each pixel.

0

1

e.g. monochrome (single color)

2 possible values

Uses up 1 bit of space

3) Monitor quality (effects of color depth)
• 16 million colors

16 colors

2 colors

256 colors

Tradeoff between resolution and color depth
• There is a limit for both

e.g. 16 bit color at 1600 x 1280 = 2 bytes per pixel * 1600 columns of pixel * 1280 rows of pixels = 4.096 MB

dot pitch

4) Monitor quality (dot pitch)
• Dot pitch is the distance between the center of each color dot (mm)

3 guns form 1 color dot

Refresh rate of monitors
• How fast the screen is redrawn

Again there is a tradeoff between resolution and refresh (70 Hz / 70 times per second is usually a good minimum)

Types of monitors
• CRT – use three electron guns (shown on previous slides)

2) LCD (flat screen) – use a liquid crystal display

CRT’s vs. LCD’s
• CRT
• Cost less for the same quality
• Sharper images possible (more colors, higher resolution)
• Can view images from any angle
• LCD
• Less eye strain (no flicker and less glare)
• Uses less space
• Use less power
• Weigh less
What is the difference between storage and memory?
• Memory
• keep the information for a shorter period of time
• faster
• more expensive
• “scrap paper for the computer”
• Storage
• the information is retained longer
• slower
• cheaper
• “file cabinet for the computer”
Types of storage
• Optical
• CD-ROM
• DVD
• 2) Magnetic
• Hard drives
• Floppy disks
1) Optical CD & DVD
• CD-R: needs a CD-burner to create (record) to a CD
• Cheap and portable storage of a lot of data (650 MB)
• CD-RW: can write and erase CD to reuse it (rewritable)
1) CD’s and DVD’s (recording information)
• Use special compounds

By default the surface of the CD is reflective

A weak laser (read laser) is shot at the disc to determine the reflective portions

CD

The melted part no longer reflects light

1) CD’s and DVD’s (recording information)
• A strong laser (write laser) heats selected parts of the disc.

CD

The re-melted part reflects light again

1) CD’s and DVD’s (erasing the information)
• A laser (erase laser) heats selected parts of the disc (not quite as hot as a write laser).

CD

2) Magnetic drives (hard drives)
• Stores a lot of information (~20 GB – 80 GB)
• Slower than memory (but faster than other forms of storage)
• Spin rate (5400, 7200, 10000 rpm)
2) Magnetic drives (floppy)
• Pros
• Portable
• Cheap
• Cons
• Slow
• Low storage capacity (1.44 MB)
2) Magnetic drives (structure)

A cylinder (a bunch of sectors on different platters, one on top of the other – hard drives only)

Motherboard (Systemboard, Mainboard)
• Many parts of the computer are attached to it.
Buses
• Connects together the different parts of the computer.
• Used for the transfer of information.
• Width determines its speed
Ports
• Are used to connect the computer to outside devices
• Serial, parallel
• Ports on older computers (slower, 1 port to one device)
• USB (Universal serial bus)
• Standard on newer computers (faster, up to 127 devices on 1 port)
• Firewire
• Fast (video)
Printers
• Allows text or graphics to be printed out on paper
• Common types
• Inkjet
• Laser
How inkjet printers work.
• Use a series of nozzles to spray drops of ink directly on the paper

Ink nozzles

Characteristics of Inkjet printers
• Printer costs less (black and white ~ \$70.00, color ~\$100.00+)
• Cost per page is more
• Slower
• Text is lower quality, color pictures may be higher quality
How laser printers work
• Use a laser to produce patterns on an ink drum using static electricity
Characteristics of Laser printers
• Printers cost more (black and white ~ \$300.00+, color ~\$3000.00+)
• Cost per page is less
• Faster
• Text is higher quality, color pictures may be lower quality

Cameras

Scanners

Joysticks

Speakers

Some other peripherals
Summary
• Important concepts
• What is hardware and what are common units of measurement used
• Processors – what do they do, what are their characteristics, types of processors
• Memory – what is it, types of memory
• What is the purpose of an input device, types of input devices
• What is an output device, types of output devices
• General characteristics of computer monitors
• Storage devices – different types and how they work
• Other parts of a computer (beyond the simple model) – motherboard, buses, ports
• Common peripherals (printers, scanners, cameras)