Chapter 06 The System Unit

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Competencies

After you have read this chapter must be able to:

1. Describe the six basic types of system units

2. Discuss how a computer can represent numbers and encode characters electronically

3. Describe each of the major system unit components.

4. Discuss microprocessors, including microprocessor chips and specialty processors

5. Discuss memory including RAM, ROM, and flash memory

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Competencies

6. Discuss expansion slots and cards

7. Describe five principal types of expansion buses

8. Compare standard, specialized, and legacy ports

9. Discuss power supply for desktop and notebook computers

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Introduction

Speed, capacity, and flexibility determine the power of microcomputers.

Knowledge of a computers power allows you to make good buying decisions and to determine if your current system will run new applications.

Competent end users need to understand the basic principles of how microcomputers are put together.

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What is the system unit

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System Unit

Also known as the system cabinet is a container that houses most of the electrical components that make up a computer system.

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Tais

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System Unit Types

Six basic types of system units:

1. Desktop System Units.

2. Media Center System Units.

3. Notebook System Units.

4. Netbook system units.

5. Tablet PC System Units.

6. Handheld Computer.

System Units.

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System Unit Types

1. Desktop System Units:

Contain the system electronic components and selected secondary storage devices .

Input& output device such as a mouse, keyboard, and monitor, are located outside the System Unit.

Designed to be placed either horizontally or vertically.

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2. Media center System Units:

Bluer the line between desktop system unit& entertainment devices.

Use powerful system hardware with specialized graphics card for interfacing with television and other home entertainment devices .

System Unit Types

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System Unit Types

3. Notebook System Units:

Portable and much smaller .

Contain the system electronic components and selected secondary storage devices .

, input devices( keyboard& pointing device).

Located outside the system units , the monitor attached by hinges.

Are often called laptops.

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System Unit Types

4. Netbook System Units:

Are similar to Notebook System Units.

Smaller, less expensive.

Designed to support on the- go web browsing and e-mail access.

Reduce space and weight by leaving out components ( optical drivers)

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System Unit Types 5. Tablet PC System Units:

Similar to notebook system units, Highly portable devices, Support the use

of styles or pen to input commands and data.

There are two basic types : ( 1. effectively notebook computer that

accepts styles input and has monitor . 2. it has a removable keyboard , can be

used like traditional notebook computer. With the keyboard detached , the unit is

more portable and all inputs is typically with a stylus.

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System Unit Types

6. Handheld Computer System Units:

The smallest and are designed to fit into palm of one hand.

Contained an electronic components, secondary storage devices.

The most widely used hand held computers are PDAS & smart phone.

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Notes

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Electronic Data and Instructions Computers only recognize digital signals

1.Numeric representation( ( : On/off Electrical states .

Characters represented by 0s (off) and 1s (on)

The binary system consists of two digits 0 and 1:

1 positive charge& 0 no charge.

Each 0 or 1 is called a bit short for binary digit.

Bits are combined into groups of eight bits called bytes.

Smallest character = bit; eight bits = 1 byte or one

character.

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How can a computer provide representations of the nonnumeric characters we use to communicate?

The answer:

By character encoding schemes or standers .

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2. Character Encoding Schemes:

Three types of binary coding schemes:

:

1) ASCII - American Standard Code for Information Exchange: -

2) EBCDIC .

3) Unicode .

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Electronic Data and Instructions

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2. Character Coding Schemes:

1)ASCII - American Standard Code for Information Exchange:

primarily desktop.(Historically microcomputer used .ASCII to represent characters .)

2)EBCDIC - Extended Binary Coded Decimal Interchange Code:

primarily mainframe and super.(Mainframe computer used EBCDIC.

ASCII& EBCDIC are limited(ASCII uses 7 bits to represent each character( 128 total characters could be represented)

This was fine for most characters in English Language but was not large enough to support other languages.

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Electronic Data and Instructions

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2. Character Coding Schemes:

3) Unicode .

- handles languages with large numbers of characters.

The most widely used character encoding slandered and is recognized by virtually every computer system .

Uses a variable number of bits to represent each character, which allows non- English characters and special characters and special characters to be represented.

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Electronic Data and Instructions

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