PC Parts

Identifying PC parts and their functions.

Binumon JosephS1 MCANo : 23AJCE

Introduction

Personal Computers (PCs) and PC-based equipment are based on common hardware.

Here we’ll examine common hardware components.

External components

Visible to the end-user Required for the PC to function Consist of

– Case– Monitor– Keyboard– Mouse

Case (we’ll look inside later)

The case is the “box” that holds the internal components of the PC. It protects those delicate components from dust and debris.

Monitor

The monitor is the main output component used on a PC. It’s where the computer is able to show you what it, and you, are doing.

Keyboard

The keyboard is the main input device you use with a computer or PC-based equipment.

Mouse

On any PC that uses graphics (pictures), a mouse is an essential input device that allows you to control the PC.

Internal Components

Remember the case? We said it contained internal components.

Internal components are the parts of the computer that do most of the work, though they are behind the scenes.

Understanding their basic functions is important to understanding the PC as a whole.

Internal Components

Motherboard CPU Drives Expansion cards Memory Power supply

Motherboard

The motherboard (main board, system board) is a large circuit board which all other PC components connect to in some way.

Motherboard

CPU

The CPU (Central Processing Unit) is the brain of the PC. All work done by the PC involves the CPU in some way. The CPU plugs into the motherboard.

CPU

Drives

There are many kinds of drives in a computer: CDROM drives, hard drives, floppy drives, ZIP drives, tape drives, pen drives. The basic function of all drives is to store information (more on this later).

Hard drive

Floppy drive

CD- or DVD-ROM drive

RAM

Random Access Memory (RAM) is memory that the CPU uses when performing its tasks.

RAM consists of chips that plug into the motherboard. In general, the more RAM you have, the better.

Expansion Cards

Expansion cards are circuit boards that plug into the motherboard to expand its capabilities. Sound cards are an example. One required expansion card is the video card, which connects to the monitor.

Video card

Normally an expansion card, but sometimes built into the motherboard (integrated), the video card has 15 holes, in three rows of five.

Power Supply

The power supply is crucial to the PC. It converts power from the wall outlet into power the PC can use. It powers all internal components, including the motherboard and drives.

Communication Ports

In industry, non-integrated PCs must connect to external machines, such as:– CNC machines– Automobiles– Robotic devices

These connections are made via communication ports.

Communication Ports

Common communication ports are:– Keyboard– Mouse – Serial– Parallel– Modem– Network Interface Card (NIC)– USB

Keyboard

Barcode readers often attach to keyboard ports.

Keyboard ports appear in DIN5 and PS/2 or Mini-DIN6 (below).

Mouse

Some input devices connect via a mouse port. Common mouse ports are PS/2 (Mini-DIN6) on the

left and serial (9 pin male) on the right. Don’t connect a mouse-port device to a keyboard

port.

Serial

Serial ports are fairly slow ports that can transmit data over a long distance (hundreds of feet).

Serial ports are either 9 or 25 pin. Serial ports are male (plugs) on the PC.

Parallel

Parallel ports are normally used for output to printing devices.

Parallel ports are 25 pin female (socket) on the PC.

Modem

Modems are normally expansion cards that contain two phone jacks.

They communicate via phone lines to remote devices.

Network Interface Card (NIC)

NICs are expansion cards that connect PC devices to networks via special network cable.

Many connections to external machines are now made via NICs, which normally have one port.

USB

A popular technology to connect to external devices is USB, which can support 127 devices.

USB will eventually replace keyboard, serial, and parallel ports.

Compare Communications Ports

Parallel is normally used for output only. Keyboard and mouse ports are normally

input only. Serial, NIC, Modem and USB are bi-

directional (input and output).

Storage Devices

Storage is easiest to think of in terms of primary and secondary.

Primary storage is used by the CPU. The primary example is RAM. Primary loses information without power.

Secondary devices can store data without power. Drives are the main secondary storage devices.

3.5 inch floppy drive

Hard drive

CDROM drive

Storage Reminders

RAM stores information that is currently active.

Information in RAM must be saved to secondary storage or it will be lost when power is removed.

Secondary storage keeps data unless the user removes it (or the device fails).

RAM vs. ROM

RAM stands for Random Access Memory

RAM changes constantly as the CPU needs different items in memory based on the user’s requests.

RAM is lost when power is removed.

ROM

•ROM stands for Read Only Memory

•ROM does not change.

•ROM is not lost when the power is removed from a PC.

•ROM stores key instructions that the computer needs to boot up and operate.

Computer Hardware Components

– How did the computer become known as the stored-program computer?

• Do they all have the same characteristics?

– Memory on chips and memory on magnetic media, how do they differ?

– What do you look for when comparing memory devices?

– How is information moved around within the computer?

– How can you help your computer run better?

Basic Concepts of Computer Hardware

This model of the typical digital computer is often called the von Neumann computer.

– Programs and data are stored in the same memory: primary memory.

– The computer can only perform one instruction at a time.

CPU(Central Processing Unit)

InputUnits

OutputUnits

Primary Memory

Basic Concepts of Computer Hardware Input/Output (I/O): Refers to the

process of getting information into and out of the computer.– Input: Those parts of the computer

receiving information to programs.– Output: Those parts of the computer that

provide results of computation to the person using the computer.

Sources of Datafor the Computer

Two types of data stored within a computer:– Original data or information: Data being

introduced to a computing system for the first time. • Computers can deal directly with printed text, pictures,

sound, and other common types of information.

– Previously stored data or information: Data that has already been processed by a computer and is being stored for later use.

• These are forms of binary data useful only to the computer.

• Examples: Floppy disks, DVD disks, and music CDs.

Input Devices

Two categories of input hardware:– Those that deal with original data.– Those that handle previously stored data.

Input Devices

Input hardware: Those that deal with original data.– Keyboard– Mouse– Voice recognition hardware– Scanner– Digital camera

Digitizing: The process of taking a visual image, or audio recording and converting it to a binary form for the computer.– Used as data for programs to display, play or manipulate the

digitized data.

Input Devices

Connecting Hardware to the computer:– Hardware needs access through some general

input/output connection.• Port: The pathway for data to go into and out of the

computer from external devices such as keyboards. – There are many standard ports as well as custom

electronic ports designed for special purposes.

– Ports follow standards that define their use.

» SCSI, USB: Multiple peripheral devices (chain).

» RS-232, IDE: Individual peripheral devices.

• Peripheral device: A piece of hardware like a printer or disk drive, that is outside the main computer.

Input Devices

Connecting Hardware to the computer: (continued)– Hardware needs software on the computer

that can service the device.• Device driver: Software addition to the

operating system that will allow the computer to communicate with a particular device.

Input Devices

Common Basic Technologies for Storing Binary Information:– Electronic– Magnetic– Optical

Input Devices

Electronic Circuits– Most expensive of the three forms for

storing binary information.– A flip-flop circuit has either one electronic

status or the other. It is said to flip-flop from one to the other.

– Electronic circuits come in two forms:• Permanent

• Non-permanent

Input Devices

Magnetic Technology– Two parts to most of the magnetic forms of

information storage:• The medium that stores the magnetic information.

– Example: Floppy disk. Tiny spots on the disk are magnetized to represent 0s and 1s.

• The device that can “read” that information from the medium.

– The drive spins the disk.

– It has a magnetic sensing arm that moves over the disk.

– Performs nondestructive reading.

Input Devices

Optical– Uses lasers to “read” the binary information

from the medium, usually a disc.• Millions of tiny holes are “burned” into the

surface of the disc.• The holes are interpreted as 1s. The absence

of holes are interpreted as 0s.

Input Devices

Secondary Memory Input Devices– These input devices are used by a computer to

store information and then to retrieve that information as needed.

• External to the computer.• Commonly consists of floppy disks, hard disk drives, or

CD-ROMs.

– Secondary memory uses binary.• The usual measurement is the byte.

– A byte consists of 8 binary digits (bits). The byte is a standard unit.

Input Devices

The four most important characteristics of storage devices:– Speed and access time– Cost / Removable versus non-removable– Capacity– Type of access

Input Devices

Speed (Access time) - How fast information can be taken from or stored onto the computer memory device’s medium.– Electronic circuits: Fastest to access.

• 40 billionths of a second.

– Floppy disks: Very slow in comparison.• Takes up to 1/2 second to reach full speed

before access is even possible.

Input Devices

Cost– Megabyte: A Million bytes.

– Gigabyte: A billion bytes.

– Two parts to a removable secondary storage device:• The cost of the medium. (Cheaper if bought in quantity)

• The cost of the drive.

Examples: Cost for drive Cost for medium

Floppy drive (1.4MB) 59.00 .50

Zip 100 (100 MB) 99.00 10.00

CD-WR (650 MB) 360.00 and up 1.00

Input Devices

Capacity - The amount of information that can be stored on the medium.Unit Description Approximate Size

1 bit 1 binary digit1 nibble 4 bits1 byte 8 bits 1 character1 kilobyte 1,024 bytes 1/2 page, double spaced1 megabyte 1,048,576 bytes 500,000 pages

1 million bytes1 gigabyte 1,073,741,824 bytes 5 million pages

1 billion bytes1 terabyte 1 trillion bytes 5 billion pages

Input Devices

Type of Access• Sequential - Obtained by proceeding through

the storage medium from the beginning until the designated area is reached (as in magnetic tape).

• Random Access - Direct access (as in floppy and hard disks).

Primary Memory

Primary storage or memory: Is where the data and program that are

currently in operation or being accessed are stored during use. – Consists of electronic circuits: Extremely fast and

expensive.– Two types:

• RAM (non-permanent) – Programs and data can be stored here for the computer’s

use.– Volatile: All information will be lost once the computer shuts

down.

• ROM (permanent)– Contents do not change.

The Central Processing Unit

The Central Processing Unit ( CPU)– Often referred to as the “brain” of the computer.– Responsible for controlling all activities of the computer

system.– The three major components of the CPU are:

1. Arithmetic Unit (Computations performed)

Accumulator (Results of computations kept here)

2. Control Unit (Has two locations where numbers are kept)

Instruction Register (Instruction placed here for analysis)

Program Counter (Which instruction will be performed next?)

3. Instruction Decoding Unit (Decodes the instruction)

– Motherboard: The place where most of the electronics including the CPU are mounted.

Output Devices

Output units store and display information (calculated results and other messages) for us to see and use.– Floppy disk drives and Hard disk drives.

– Display monitors: Hi-resolution monitors come in two types:

• Cathode ray tube (CRT) - Streams of electrons make phosphors glow on a large vacuum tube.

• Liquid crystal display (LCD) - A flat panel display that uses crystals to let varying amounts of different colored light to pass through it.

– Developed primarily for portable computers.

Output Devices

Audio Output Devices– Windows machines need special audio card for audio

output.– Macintosh has audio playback built in.– Audio output is useful for:

• Music– CD player is a computer.– Most personal computers have CD players that can access both

music CDs and CD-ROMs.

• Voice synthesis (becoming more human sounding.)• Multimedia• Specialized tasks (i.e.: elevator’s floor announcements)

Output Devices

Optical Disks: CD-ROM and DVD– CD-ROM (Compact Disk - Read Only Memory)

• By its definition, CD-ROM is Read Only.• Special CD drives “burn” information into blank CDs.

– Burn: A laser is used to “burn” craters into the surface to represent a binary 1.

– Two main types of CDs:

» CD-R (Compact Disk - Recordable)

» CD-WR (Compact Disk - ReWritable)

• It takes longer to write to a CD-R than a hard drive.• Special software is needed to record.

Output Devices

DVD (Digital Versatile Disk)– Allows up to 17 gigabytes of storage (from

4.7 GB to 17 GB).– Compatible with older CD-ROM

technology.– The four versions of the DVD:

Output Devices

Storage Requirements: How much storage capacity is needed for…

– One keystroke on a keyboard. 1 byte (8 bits)– One page single-spaced document. 4.0 K– Nineteen pages formatted text. 75 K– One second of high-fidelity sound. 95-110 K– Complete word processing program. 8.4 MG

Storage Capacity: How much data can be stored on…

– One inch of 1/2 in. wide magnetic tape. 4 K– One 3 1/2” floppy disk, high density. 1.4 MG– One Compact Disk. 650 MG– One DVD. up to 17 GB

Moving InformationWithin the Computer How do binary numerals move into, out of,

and within the computer?– Information is moved about in bytes, or multiple

bytes called words.• Words are the fundamental units of information.• The number of bits per word may vary per computer.• A word length for most large IBM computers is 32 bits:

Moving InformationWithin the Computer

Bits that compose a word are passed in parallel from place to place.

– Ribbon cables: • Consist of several wires,

molded together.• One wire for each bit of

the word or byte.• Additional wires

coordinate the activity of moving information.

• Each wire sends information in the form of a voltage pulse.

Moving InformationWithin the Computer

Example of sending the word WOW over the ribbon cable

– Voltage pulses corresponding to the ASCII codes would pass through the cable.

Packaging the Computer

The many physical forms of the general purpose computer:

– All follow general organization:

• Primary memory• Input units• Output units• Central Processing Unit

– Grouped according to speed, cost, size, and complexity.

Super Computers

Mainframe Computers

Minicomputers

Microcomputer

Palmtop Computer

Calculator

Fast Expensive Complex Large

Slow Cheap Simple Small

Software Tools for Maintaining Your Computer Hardware Utility Programs exist that can help diagnose and solve computer

hardware problems.

– Four major problem areas where utility programs are helpful:

• Finding and fixing problems.– Testing Input/Output peripherals.– Testing RAM, motherboard, video cards.– Recovering deleted files or fixing damaged disks.

• Improving computer performance.– De-fragmenting a disk (Packs all files closer together).

• Preventative maintenance.• Troubleshooting.

– Locates incompatible programs.

Overview

The PC consists of common external and internal components.

Each component has a specific task. Communication ports connect to

external devices. Storage devices are classified and

primary or secondary.

Thank You…