Computer Concepts 8

1
1
1
1
Chapter 4 File Management, Virus Protection, and
Backup
1
Chapter 1 Computer, Internet, Web, and E-Mail
Basics
2
Chapter 2

• Data representation
• Microprocessors and memory
• Storage devices

3
Data Representation How do computers represent
data?

• Data representation
• Converts letters, sounds, and images into a form
  computers can understand
• Digital device
• Discrete data, such as the digits 1 and 0
• Computers are digital
• Analog device
• Continuous data

Page 60
4
How does a computer represent numbers?

• The binary number system (base 2)
• Only two digits 0, and 1
• Decimal numbers and their binary equivalents

Page 60
5
How can a computer represent text using bits?

• Character data
• letters, symbols, and numerals
• not used in arithmetic operations
• ASCII
• 7 bits per character
• 27 128 characters
• Extended ASCII
• 8 bits per character
• 28 256 characters
• Unicode
• 16 bits per character
• over 65,000 characters
• Used for foreign language support

Page 61
6
Bits, bytes, everything nice

• A bit is one binary digit (b)
• 0
• A byte is 8 bits (B)
• 0010 0100
• Kilobit (Kb) is 1,024 bits
• Kilobyte (KB) is 1,024 bytes
• Megabyte (MB) is 1,048,576 bytes
• Gigabyte (GB) is 1,073,741,824 bytes

Page 63
7
Whats a computer chip?

• An integrated circuit
• Thin slice of silicon crystal packed with
  microscopic circuit elements

Page 64
8
What types of computer chips are there?
Page 65
9
What is a CPU?

• An integrated circuit (computer chip) designed to
  process instructions

Page 68
10
How does a CPU work?

• The CPU has two parts
• ALU (arithmetic logic unit)
• Performs arithmetic operations
• Performs logical operations
• Uses registers to hold data being processed
• Control unit
• Directs and coordinates processing

Page 68
11
What is RAM?

• Random Access Memory
• Volatile memory
• A temporary holding area for data, application
  program instructions, and the operating system
• As you type, characters are held in RAM

Page 72
12
How much RAM does my computer need?

• RAM is primary storage (main memory)
• Most computers have 128 MB - 2 GB RAM
• Depends on software you use
• You can upgrade RAM
• Disk storage can be used to simulate RAM
• Virtual memory
• Not as fast as RAM

Page 73
13
Do all computers use the same type of RAM?

• RAM components vary in speed, technology, and
  configuration
• Speed is measured in nanoseconds
• 1 nanosecond (ns) is 1 billionth of a second
• It can also be expressed in MHz
• Millions of cycles per second

Page 74
14
How is ROM different from RAM?

• ROM Read Only Memory
• Holds the computers startup (boot) routine
• Permanent and non-volatile
• Only way to change the instructions in ROM is to
  replace the chip

Page 74
15
What is CMOS Memory?

• Semi-permanent storage
• Stores configuration settings
• Ex Amount of RAM
• Requires very little power to retain its contents
• Runs off a battery on the system board

Page 75
16
Where does a computer store its basic hardware
settings?
Page 75
17
How is data stored?

• Storage medium
• the disk, tape, CD, DVD, paper or other substance
  that contains data
• Storage device
• the mechanical apparatus that records (writes)
  and retrieves (reads) data from a storage medium

Page 78
18
How does magnetic storage work?

• Data is stored as magnetized microscopic
  particles on a disk or tape surface
• Read-write head - mechanism in the disk drive
  that reads and writes data

Page 79
19
How does optical storage work?

• Stores data as microscopic light spots (lands)
  and dark spots (pits) on the disk surface
• Less susceptible to damage than magnetic media

Page 79
20
How do CD and DVD drives work?

• Recordable technology
• uses a laser to change the color in a dye layer
  sandwiched beneath the clear plastic disk surface

• Rewritable technology
• uses phase change technology to alter a crystal
  structure on the disk surface

Page 86
21
Is there a difference between CD and DVD
technology?

• CD
• Holds 680 MB of data
• up to 80 minutes of music
• DVD
• Holds about 4.7 GB of data
• A double layer DVD has two recordable layers on
  the same side
• Can store 8.5 GB of data

Page 86
22
How does solid state storage work?

• Stores data in a non-volatile, erasable,
  low-power chip
• Some solid state storage requires a device called
  a card reader to transfer data to or from a
  computer
• Provides faster access to data than magnetic or
  optical storage technology because it includes no
  moving parts

Page 80
23
Why use solid state storage?

• Portable
• Fast access to data
• Uses very little power
• Examples
• USB flash drive
• CompactFlash card
• MMC
• SecureDigital
• SmartMedia

Page 88
24
What is floppy disk technology?

• A floppy disk
• A round piece of flexible mylar plastic covered
  with a thin layer of magnetic oxide and sealed
  inside a protective casing

Page 81
25
How much data can a floppy disk and a Zip disk
hold?

• 3½ floppy disks can store 1.44 MB
• Zip disks come in 100 MB, 250 MB, and 750 MB
  versions

Page 82
26
How does a hard disk work?

• Hard disk platter
• a flat, rigid disk
• made of aluminum or glass
• coated with magnetic iron oxide particles
• density far exceeds floppy disk
• Hard disk
• one or more platters and their associated
  read-write heads
• Preferred type of main storage

Page 83
27
Can I add storage devices to my computer?

• Devices can be added into empty drive bays

Page 80