This document discusses the basic hardware components of computers, including input/output devices, the central processing unit (CPU), memory, storage, and buses. It explains that CPUs contain functional units like the control unit and arithmetic logic unit to process instructions. Memory is used to store instructions and data temporarily, and comes in varieties like RAM, ROM, and cache. Buses connect the CPU to other components, and ports provide connections to devices like monitors, speakers, and storage. The document also touches on factors to consider when choosing a computer, like processor speed and memory, and discusses green computing practices.

1. Digital Planet:
Tomorrow’s Technology and You
Chapter 2
Hardware Basics
Inside the Box
Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall

2. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
What Computers Do
Four basic operations:
 Receive input: Accept information from outside world
 Process information: Perform arithmetic or logical
operations on information
 Produce output: Communicate information to outside
world
 Store information: Store and retrieve information from
memory and storage devices
2

3. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
What Computers Do (cont.)
Hardware components
• Input devices
• Output devices
• Microprocessor (CPU)
• Memory and storage devices
• Primary storage - RAM
• Secondary storage – Disk Drives
• Peripherals
3

4. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 4
How do computer circuits manipulate
data?
• ALL computers are electronic, digital devices
• Digital devices work with discrete data, such as
digits 1 and 0, or like a light switch – on or off
• These 1s and 0s are referred to as binary digits or
shortened to bits
• Computers use sequences of bits to digitally
represent numbers, letters, punctuation marks,
music, pictures, and videos
Practical Computer Literacy, 2nd edition
Chapter 1

5. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Bit Basics
 Bit: From Binary digit
• Smallest unit of information computer can process
• Can have one of two values: 0 or 1
 Byte
• Collection of 8 bits
• Can represent 256
different messages
(256 = 28)
5

6. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Bits as Numbers
 Denotes all numbers with combinations of 0s and 1s
 Decimal numbers automatically converted to binary
 Binary number processing hidden from user
6
Decimal Binary Decimal Binary
0 0000 5 0101
1 0001 6 0110
2 0010 7 0111
3 0011 8 1000
4 0100 9 1001

7. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Bits as Codes
• Codes represent each letter,
digit, and special character
• ASCII: Most widely used
• Each character is a unique 8-bit
code
• 256 unique codes for 26 letters,
10 digits, special characters
• Unicode: Supports more than
100,000 unique characters
7

8. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
The CPU: The Real Computer
 CPU often called “processor”
 Performs transformations of input into output
 Interprets and executes instructions in programs
 Performs arithmetic and logical data manipulations
 Communicates with other parts of the computer system indirectly through
memory
Modern Microprocessor
• Complex collection of electronic circuits
• CPU housed with other chips on circuit board
• Circuit board containing computer’s CPU is called motherboard
8

9. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Performance
 Some processors faster than others
 Performance is determined by:
• Speed of internal clock—measured in gigahertz (GHz)
• Architecture of processor
• Number of bits processor can process at one time
• Typically 32 or 64 bits—called word size
9

10. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Performance (cont.)
 Multicore Processors
• Single chip contains
multiple CPUs (cores)
• Run simultaneously
• Divide work
• Most new PCs have
at least two cores.
• Quad core becoming
common
10

11. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
 Typical CPU is divided into several functional units:
• Control unit
• Arithmetic logic unit (ALU) includes registers
• Decode unit
• Bus unit
• Prefetch unit
 These units work together to complete the execution
of program instructions.
11
The CPU – How it works (p.52-53)

12. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
The Computer’s Memory
 Random access memory (RAM)
• Most common type of primary storage
• Stores program instructions and data temporarily
• Memory locations have unique addresses
• Volatile—disappears when power is turned off
• Called DIMMS. Rated by both size and speed.
12

13. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
The Computer’s Memory (cont.)
 Read-only memory (ROM)
• Information is etched on chip when manufactured
• Stores start-up instructions and other critical information
 Flash memory
• Can be written and erased repeatedly
• Used for digital cameras, cell phones, handheld computers
13

14. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Slide 14
MEMORY CACHE
Cache used by the central processing unit of a
computer to reduce the average time to access
memory. The cache is a smaller, faster memory
which stores copies of the data from the most
frequently used main memory locations. When
the processor needs to read from or write to a
location in main memory, it first checks whether
a copy of that data is in the cache. If so, the
processor immediately reads from or writes to
the cache, which is much faster than reading
from or writing to main memory.

15. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Buses
 Information travels between components on the
motherboard through wires called internal buses or
just buses. Typically have 32 or 64 wires (data paths)
 Buses: Bridges between processor and RAM. Bus
speed is one of the most important factors in
determining a computer’s performance!!
 Buses connect to:
• Storage devices in bays
• Expansion slots
• External buses and ports
15

16. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Ports
 Computer has variety of ports to meet diverse needs
• Video port(s) to connect monitors
• Audio ports to connect speakers and/or headphones
• USB ports to connect keyboards, pointing devices,
printers, cameras, disk drives, portable storage
devices, and more
16

17. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Which Computer to BUY??
Dell A1 3.3GHz Intel 6GB Ram
$599.99
• Windows 7
• 15 inch LCD Display
• 3 Year Warranty
• 750 GB Hard Drive
Dell A2 2.8GHz Intel 4GB Ram
$799.99
• Windows 7
• 15 inch LCD Display
• 3 Year Warranty
• 500 GB Hard Drive
17

18. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Which Computer to BUY??
Dell A1 3.3GHz Intel 6GB Ram
• Windows 7
• 15 inch LCD Display
• 3 Year Warranty
• 750 GB Hard Drive (5400 rpm)
• 32 Bit Processor
• 32 Bit 400 MHz Bus
• 2 GB 2.5 GHz L2 Cache
Dell A2 2.8GHz Intel 4GB Ram
• Windows 7
• 15 inch LCD Display
• 3 Year Warranty
• 500 GB Hard Drive (7200 rpm)
• 64 Bit Processer
• 64 Bit 800 MHz Bus
• 3 GB 3.3 GHz L2 Cache
18

19. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Green Computing
 When compared to other industries the computer
industry is relatively easy on the environment.
 The manufacture and use of computer hardware and
software does have a significant environmental
impact.
 You have some control over the environmental
impact of your computing activities.
19

20. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall
Green Computing (cont.)
• Buy green equipment
• Take advantage of energy
saving features
• Turn off your computer
when you are away
• Save energy, not screens
• Avoid moving parts
20