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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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## PowerPoint Slideshow about 'Introduction to hardware' - LeeJohn

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Presentation Transcript

• Concepts covered

• Units of measurement

• Processors

• Memory

• Input and output

• Storage

• Peripherals

### Introduction to hardware

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

• 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)

• 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)

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

Processor

(maybe not…)

• The brains of a computer

• 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!

• 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)

• 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 (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.

• 1) RAM

• 2) ROM

• 3) Caches

• Often used for short term storage of information

• 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

• ROM

• PROM

• EPROM

• EEPROM

• Flash Memory (e.g., a computer BIOS, memory for game consoles)

• 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

• Used by a person to communicate to a computer.

Person to computer

• Keyboard

• Mouse

• Displays information from the computer to the a person.

Computer to a person

• A computer monitor

• Images are displayed with dots (pixels)

Picture from Beekman

• Size

• Resolution

• Color depth

• Dot pitch

Measured diagonally

• Columns of pixels x Rows of pixels

• 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

• 16 million colors

16 colors

2 colors

256 colors

• 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

4) Monitor quality (dot pitch)

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

3 guns form 1 color dot

• 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)

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

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

• 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

• 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”

• Optical

• CD-ROM

• DVD

• 2) Magnetic

• Hard drives

• Floppy disks

• 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)

• 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

1) CD’s and DVD’s (recording information)

• A strong laser (write laser) heats selected parts of the disc.

CD

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

• 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)

• Pros

• Portable

• Cheap

• Cons

• Slow

• Low storage capacity (1.44 MB)

Tracks (inside circles)

2) Magnetic drives (structure)

Sectors (wedges)

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

• Many parts of the computer are attached to it.

• Connects together the different parts of the computer.

• Used for the transfer of information.

• Width determines its speed

• 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)

• Allows text or graphics to be printed out on paper

• Common types

• Inkjet

• Laser

• Use a series of nozzles to spray drops of ink directly on the paper

Ink nozzles

• 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

• Use a laser to produce patterns on an ink drum using static electricity

• 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

Scanners

Joysticks

Speakers

Some other peripherals

• 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)