meljun cortes computer information processing chapter 2 with notes

7/31/2019 MELJUN CORTES Computer Information Processing Chapter 2 With Notes

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CCT101: Chapter 2

The Components in the System Unit


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OBJECTIVES

Identify the components in the system unit and explain theirfunctions

Explain how the CPU uses the four steps of a machine cycleto process data

Compare and contrast various microprocessors on the market

today Define a bit and describe how a series of bits is used to

represent data

Differentiate between the various types of memory

Describe the types of expansion slots and expansion cards inthe system unit

Explain the difference between a serial and a parallel port


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THE SYSTEM UNIT

System unit

electronic components of the computer that are used to

process data


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CPU AND MICROPROCESSOR

CPU (processor)

Interprets and carries out the basic instructions thatoperate a computer

Microprocessor

Pentium processors


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The Components of CPU

The Control Unit

The Arithmetic/Logic Unit

Registers


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The Control Unit

A component of the CPU that directs and coordinates

most of the operations in the computer

Fetch - get the next instruction from

memory

Decode - translate the instruction

Execute - carry out the command

Store - write the result to memory


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The Control Unit

Instruction time or I-Time

The times it takes to fetch

Execution time or E-Time

The times it takes to decode and execute

Speed is measured in MIPS (million instructions per

second)

Current PCs can process more than 300 MIPS


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The Arithmetic/Logic Unit

Performs the execution part of the machine cycle

Arithmetic (addition, subtraction, multiplication,

division)

Comparison (greater than, equal to, less than)

Logical (AND, OR, NOT)


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Registers

Temporary storage locations used by the CPU

Storing location of where instruction was fetched Storing an instruction while it is being decoded

Storing data while the ALU processes it

Storing the results of a calculation


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Intel Pentium

CPU numbers could not be trademarked

Intel identify their microprocessor with names

AMD (Intel-compatible)

Same internal design or architecture as Intel Perform same function

Less expensive

Motorola PowerPC

Used in Apple Macintosh and Power Macintosh Systems

Increased the speed of processor

Alpha

Used primarily in workstations and high-end servers

Microprocessor Comparison


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Types of MICROPROCESSOR

Coprocessors

Special processor chip or circuit board designed to

assist the processor in performing specific tasks

Floating-point coprocessor

Math or numeric coprocessor


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Types of MICROPROCESSOR (cont.)

Parallel Processing

Using multiple processors simultaneously to execute a

program

Speeds execution

Requires special software


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DATA REPRESENTATION

Analog vs. digital

Digital

Two states

Binary number system

Combination of ones and zeroes represent

characters


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DATA REPRESENTATION

ASCII vs. EBCDIC

Sufficient for English and Western European languages

Unicode often used for others

Sending a character from the keyboard to the

computer


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MEMORY

Used to store data, instructions, and information

The operating system and other system software

Application programs

Data being processed by application programs

Bytes are stored at specific locations or

addresses


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MEMORY (cont.)

Size of memory is measured by the number of bytes

available

Kilobyte - 1,024 bytes

Megabyte - 220 bytes

Two memory types

Volatile

Nonvolatile


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MEMORY RAM

Random access memory The memory chips in the system unit

When the computer starts, operating system filesare loaded from a hard disk into RAM

Dynamic RAM (DRAM) Must be energized constantly or it loses its contents

Synchronous DRAM (SDRAM) Much faster than DRAM because it is synchronized to

the system clock

Static RAM (SRAM) Is faster and more reliable than any form of DRAM


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MEMORY RAM (cont.)

Configuring RAM

The more RAM, the more programs and files a computer can

work on at once

Software usually tells you how much RAM is required

Necessary RAM depends on what type of work the computer is

used for


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MEMORY (ROM)

Read-only memory

Cannot be modified

Contents not lost when the computer is turned off

Programmable read-only memory (PROM) Is a blank ROM chip that can place items permanently

The instructions used to program a PROM chip are called

micro-code

Flash Memory Non-volatile, but can be erased and reprogrammed


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MEMORY (CMOS)

Complementary metal-oxide semiconductor

Stores configuration information about the computer

such as type of disk drives, keyboard, and monitor Uses a battery to retain the information when the

computer is turned off


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MEMORY

(Memory Access Times)

Speed at which the processor can access

data from memory directly

Measured in nanoseconds (ns) which is one

billionth of a second


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EXPANSION SLOTS AND EXPANSION

CARDS An opening, or socket, where a circuit board can beinserted into the motherboard

Add new devices or capabilities to the computer

Three common types Video card

Sound card

Internal modem

Plug and Play Computers capability to automatically configure expansion cardsand other devices they are installed


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PORTS

Used to connect external devices to the system unit

Most located on the back of the system unit

Many types of connectors Some connectors are on the computer when purchased, others

added with expansion slots


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PORTS (Serial Ports)

Transmits one bit of data at a time

Used to connect devices that do not require fast

transmission rates

Mouse

Keyboard

Modem


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PORTS (Parallel Ports)

Connect devices that can transfer more than one

bit at a time

Usually used for printers Two newer types

EPP (Enhanced Parallel Port)

ECP (Extended Capabilities Port)

EPP and ECP use the same connector as parallel port,

but are more than ten times faster

meljun cortes computer information processing chapter 2 with notes

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