Beekman5 std ppt_02
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Transcript of Beekman5 std ppt_02
2002 Prentice Hall
Hardware Basics:Inside The Box
Chapter 2
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Topics
What Computers Do
Bits, Bytes, and Buzzwords
The Computer’s Core
The Computer’s Memory
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Thomas J. Watson, Sr.
The “emperor” of IBM
Created a culture of invention
IBM remains an industry leader and innovator
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What Computers Do
Receive
Input
Process Information
Produce
Output
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What Computers Do
Store Information
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Input Devices
The keyboard is the most common input device
Pointing devices like the mouse also receive input
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Output Devices
Computers produce information and send it to the outside world.
A video monitor is a common output device.
Printers also produce output.
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Process Information
The processor, or central processing unit (CPU), processes information and performs all the necessary arithmetic calculations.
The CPU is like the “brain” of the computer.
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Store Information
Memory and storage devicesare used to store information
Primary storage is the computer’s main memory
Secondary storage uses disks or other media
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Information
Information comes in many forms
Computers store information in digital form
Text
12 3Numbers SoundsPictures
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Bit Basics
A bit (binary digit) is the smallest unit of information can have two values: 1 or 0 can represent numbers, codes, or
instructionsOn
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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
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Bits As Codes
ASCII – American Standard Code for Information Interchange
Most widely used code, represents each character as a unique 8-bit code.
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Bits as Instruction
The computer stores instructions as collections of bits. For instance, 01101010 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.
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Bits, Bytes, and Buzzwords
Byte Kilobyte (KB) Megabytes (MB) Gigabytes (GB) Terabytes (TB)
= 8 bits
= 1 Thousand Bytes
= 1 Million Bytes
= 1 Billion Bytes
= 1 Trillion Bytes
Terms used to describe file size or memory size:
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The CPU and Memory
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
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The CPU
The CPU:
interprets and executes instructions
performs arithmetic and logical data manipulations
communicates with the other parts of the computer system.
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The 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.
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Compatibility & Speed
When purchasing a computer, selecting a CPU is very important. The two most critical factors are:
Compatibility Speed
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Compatibility
Software is written for a specific processor and may not be compatible with another CPU.
Every processor has a built-in instruction set or vocabulary of instructions that only the processor can execute.
CPUs in the same family are generally designed to be backward compatible so newer processors can process all of the instructions handled by earlier models.
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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
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Speed
Clock speed by itself doesn’t adequately describe how fast a computer can process words, numbers, or pictures.
Speed is also limited by architecture and word size.
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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.
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The Computer’s Memory
RAM (random access memory):
is used to store program instructions and data temporarily
unique addresses and data can be stored in any location
can quickly retrieve information
will not remain if power goes off (volatile)
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The Computer’s Memory
ROM (read-only memory):
information is stored permanently on a chip. contains startup instructions and other permanent data.
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Buses connect to storage devices in open areas in the box called bays.
Buses, Ports, and Peripherals
Information travels between components through groups of wires called buses.
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Busses also connect to slots inside the computer
Sockets on the outside of the computer called ports.
Buses, Ports, and Peripherals
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Buses, Ports, and Peripherals
Slots and ports also allow external devices called peripherals to be added to the system (keyboard, monitor, and mouse).
Without peripherals, the CPU and memory are like a brain without a body.
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