© paradigm publishing inc. 2-1 chapter 2 input and processing

© Paradigm Publishing Inc. 2-1

Chapter 2Input and Processing


Presentation Overview

• Input Technology

• Data Processing by Computers

• The System Unit

• The Power Supply

• Storage Bays

• The Motherboard


Input Technology

Hardware devices are grouped by how and where they are used in the 4 steps of the information processing cycle.

– Input– Processing– Output– Storage


Input Technology

What is an input device?A hardware device that allows users to enter programs, data, and commands into a computer system


Input Technology

What are some examples of input devices?


Input Technology

What are some examples of input devices?– Keyboards– Touch screens– Mice and other click devices– Pens and tablets– Optical scanners– Bar code and optical readers– Graphic and video input devices– Audio input devices


Input Technology

A computer keyboard is organized into groups of related keys.


Input Technology

Input Device: Touch Screen

allows a user to make selections from a group of options displayed on a screen by pressing a finger on a chosen object


Input Technology

Input Device: Mouse

– second most common input device– moving the mouse moves a pointer on screen

which allows users to make selections from a menu and activate program icons displayed on screen


Input TechnologyEvery movement of the mouse corresponds to the movement of the mouse pointer on the display screen.


Input TechnologyWith a touch pad, the user traces a finger on the pad, moving the pointer on the screen.

Below the touch pad there are buttons for

clicking commands.


Input Technology

What are some other input devices that haven’t been mentioned?

– Optical scanner– Bar code and optical readers– Digital camera– Webcams– Video cameras– Microphone


Input TechnologyA scanner captures text and /or images and converts them into a format the computer can understand for display and storage.


Input TechnologyA digital camera captures images by converting them from analog to digital format and storing them on a storage medium.

The pictures can be printed or inserted into a document.


Input Technology

A digital video camera can plug directly into a computer to display the recorded video.


Data Processing by Computers

What is a program? – A series of instructions, using a binary system

to switch registers on and off– Tells a computer how to perform tasks

• How to process data

• How to deliver desired information



The binary number system uses a condition similar to what happens when an electrical switch is turned on, causing current to flow.

In the binary number system, a one (1) represents an “on” state in which there is an electrical charge, and a zero (0) represents an “off” state in which there is no electrical charge.



ASCII is a coding scheme many computers, including personal computers, use.

The EBDIC coding scheme is used mainly on large computers such as IBM mainframe computers.


Data Processing by ComputersPressing a key generates an electronic signal that is converted into binary form (a byte) and stored in memory. The computer processes the digital signal and displays the character on the screen.


The System Unitthe main part of a personal computer system, containing components necessary for processing information


The Power Supply

connects the computer to AC current and converts the AC current to DC current


Storage Bays

The desktop computer shown contains a CD/DVD drive bay and a hard drive bay.


The Motherboardholds major processing and memory components, including:• Central processing unit to manipulate data• System clock to synchronize activities• Slots for RAM chips to contain temporary memory• ROM chips to contain permanent memory• Expansion slots to attach expansion cards• Ports to connect input and output devices• Buses to communicate between computer components


The MotherboardThe motherboard holds the major processing and memory components, including the CPU, RAM, and ROM chips.


The MotherboardThe Central Processing Unit

– interprets and executes the instructions for most computer operations

– on a personal computer, it is a single chip called a microprocessor, and all processing functions are contained on it

– called a CPU or microprocessor


The MotherboardThe Central Processing Unit

– performs a machine cycle, which• fetches an instruction• decodes the instruction• executes the instruction• stores the result


The Motherboard

The central processing unit (CPU) contains a control unit, arithmetic/logic unit (ALU), and registers.


The MotherboardThe machine cycle includes the four steps for reading and carrying out an instruction: fetchingdecoding executing storing


The MotherboardThe Control Unit

– directs and coordinates the overall operation of the computer

– performs machine cycle functions• fetching an instruction

• decoding an instruction


The MotherboardThe Arithmetic/Logic Unit (ALU)

executes (carries out) instructions and performs arithmetic and logical operations on data. It can • add

• subtract

• multiply

• divide

• perform logical operations, such as comparing data items


The MotherboardRegisters

– temporary storage location

– records result to memory

– types• instruction registers• data registers• storage registers


The Mother-boardA comparisonof desktop personal computer processors


The Motherboard

A comparison of notebook computer and mobile device processors


The Motherboard

Without pipelining, the computer executes an instruction after the previous instruction completes the machine cycle. This is less efficient.


The Motherboard

Processing speed is improved with pipelining. With pipelining, the computer begins executing a new instruction as soon as the previous instruction reaches the next phase of the machine cycle.


The MotherboardSystem Clock

– controls timing of all computer operations– speed is measured by number of clock pulses per

second, or hertz– one clock cycle is equal to two ticks of the clock– a CPU uses a fixed number of clock cycles to

execute each instruction


The MotherboardA multi-core processor is a CPU that includes more than complete core per physical processor, so a single integrated circuit (silicon chip) contains several processors and their cache memories.


The MotherboardRandom Access Memory (RAM)

– temporary memory in which programs and

data are stored

– performs these functions:

• accepts and holds program instructions and data• acts as CPU’s source for data and instructions and as a

destination for operation results• holds final processed information until it can be sent to

desired output or storage devices


The Motherboard

Measures of data storage


The Motherboard

Computer memory comparisons


The MotherboardCache Memory

a secondary type of processing storage • a holding area where data and instructions most

recently called by the processor from RAM are

stored

• shortens processing time


The Motherboard

Memory access times


The Motherboard

RAM chips temporarily store programs and data during the processing stage. On some computers, ROM chips contain permanent storage of the operating system and instructions for managing peripheral devices.


The MotherboardFlash Memory

– can be erased and reused or reprogrammed

– used for storing programs and data on handheld computers and devices such as digital cameras, cellular phones, and printers


The MotherboardExpansion

– Expansion slots – openings in motherboard for expansion card

– Expansion card – component that adds new functions• sound card• video card• network card• modem card


The Motherboard

Expansion cards


The Motherboard

Ports are external plug-in slots that connect devices such as monitors, keyboards, and printers to the system unit. Ports are visible on the back of the system unit.


The MotherboardPortsan external plug-in slot on a computer used to connect to a peripheral device • USB ports connect high-speed devices such as scanners and modems• serial ports connect devices such as keyboards and modems• parallel ports connect printers• video ports connect monitors• SCSI ports have faster transmission rates than parallel or serial ports


The Motherboard

Data, as bits, travel along a bus from one computer system location to another, like cars travel along a highway. Bits travel along a bus from memory to CPU, input devices to memory, CPU to memory, and memory to storage devices.


On the Horizon

Based on the information presented in this chapter and your own experience, what do you think is on the horizon?

© paradigm publishing inc. 2-1 chapter 2 input and processing

Documents

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