Computer Performance

Boot Process Sequence of events that occurs between the

time you turn on a computer and the time that it becomes ready to accept commands.

1. Power up2. Start boot program3. Power-on self-test4. Identify peripheral devices5. Load operating system6. Check configuration and customization

Purpose Run a diagnostic test to make sure everything is working. Load the operating system, so the computer can carry out

basic operations.

Binary Number System

Computers communicate through binary language.

Also referred to as Base 2 Binary Code.

Method for representing letters or numbers using only two digits, 0 and 1.

Series of switches that can be either On (an electric pulse is present)

Off (an electric pulse is not present)

= 1

= 0

Computer Hardware

Physical, touchable, material parts of a computer or other system.

Integrated Circuit (IC) Another name for a chip; small

electronic device made out of a semiconductor material.

Used for a variety of devices, including microprocessors, audio and video equipment, and automobiles.

Often classified by the number of transistors and other electronic components they contain.

Path from one component of a computer to another that data uses to travel.

Run between RAM and the microprocessor. RAM and various storage devices.

Silicon Chip Silicon is melted

sand. What the circuits are

embedded into to keep them together.

Microprocessor integrated circuit package holds a silicon chip that contains millions of transistors and other components fabricated into the silicon.

System Unit Main body of a desktop computer Consists of a metal or plastic enclosure

that contains the Motherboard Power supply Cooling fans Internal disk drives Memory modules and expansion cards

Often incorrectly referred to as the CPU, the hard disk, or the case

Motherboard

Primary component of the computer Holds the following items:

CPU (Central Processing Unit) System clock circuitry Memory

RAM (Random Access Memory) ROM (Read-Only Memory) “CMOS” memory

Expansion slots, used to add expansion cards (for example, Video or Sound cards)

CPU (Central Processing Unit) Component (microprocessor) in a digital

computer Where the actual processing takes place

Interprets instructions Processes data contained in computer programs

Often called the brain of the computer

Pentium

Name of the CPU. Fifth generation of the Intel processor. Other generations

80-88 286 386 486

System Clock Internal Clock

Regulates rate instructions are executed

Synchronizes computer components

Clock Speed Measured in units of cycles per

second, which is called Hertz (Hz) Megahertz (MHz)

Measurement used to describe the speed of the system clock.

Equal to one million cycles (or pulses) per second.

Gigahertz (GHz) Equal to one billion cycles (pulses)

per second. 1.3 GHz means that the

microprocessor’s clock operates at a speed of 1.3 BILLION cycles per second.

Memory

Where programs and data are stored while you are using them

RAM “Random Access Memory” Provides ability for a storage device to go directly to a

specific storage location without having to search sequentially from a beginning location.

Very volatile Cannot hold data when the power is off. Looses all data when power is lost.

ROM “Read-Only Memory” Drives can read data from disks, but cannot store new data

on them. One or more integrated circuits that contain permanent

instructions that the computer uses during the boot process.

Memory Measurements Bit

Each 0 or 1 Byte

8 bits Kilobyte

Approximately 1,000 bytes Exactly 1,024 bytes

Megabyte Approximately 1 million bytes Exactly 1,048,576 bytes

Gigabyte Approximately 1 billion bytes

Terabyte Approximately 1 trillion bytes

Input Devices Input devices supply data to a computer. Types of Input

Data: Raw facts given to the computer. Programs: Sets of instructions that direct the

computer. Commands: Special codes or key words the user

inputs to perform a specific task. Type on the keyboard Select from a menu Click on a command button

User Response: User’s answer to the computer’s question.

Input Device Examples

Keyboard

Touch Pad

Track Ball

Scanner

Mouse

Track Point

Joy Stick

Output Devices Display, print, or transmit the results of

processing from the computer’s memory. Types of Output

Hard Copy: Printed on paper or other permanent media.

Soft Copy: Displayed on screen or by other non-permanent means.

Categories of Output Binary numbers Text documents; for example, reports and letters Graphics; for example, charts, graphs and pictures Multimedia; combination of text, graphics, video, and

audio

Output Devices, cont. Monitor

Display device that forms an image by converting electrical signals from the computer into points of colored light on the screen.

Types CRT (Cathode Ray Tube) Flat Panel Display usually uses an LCD (Liquid

Crystal Display) to display output from the computer.

Terms Screen size: Measured diagonally (in inches) across

the screen. Resolution: Density of the grid used to display or

print text and graphics. The greater the horizontal and vertical density, the higher the resolution.

Pixels (Picture Elements): Small dots that make up the image displayed on the screen. Computer display devices use a matrix of pixels to display text and graphics.

Input/Output Devices Speakers

Sound Card

Modem

Printer Output device that

produces text or graphical images on paper.

Types Ink Jet Laser

Storage Devices Store your documents (data files) and

programs (executable files) when they are not currently in use for processing.

Data stored on these devices does not vanish when you turn off the power to the computer.

Major categories include: Magnetic Solid state Optical

Hard Disk Contains disks made of

metal and coated with a metal oxide that can be magnetized.

Rated by Storage capacity, typically tens

or hundreds of gigabytes. How fast they disks spin (in

rpm, rotations per minute), typically thousands of rpm.

Usually mounted inside the system unit.

Stores billions of characters of data; stated in forms of Megabytes Gigabytes

Floppy Disk Made of flexible Mylar

plastic coated with metal oxide that can be magnetized.

3.5” in size (older diskettes were 5.24”) holds 1.44 MB of data

Shutter protects the disk surface from dirt and fingerprints

Zip Disk Floppy disk technology

developed by Iomega Corporation.

Similar in size to a floppy diskette, but thicker.

More storage capacity than a floppy; up to 750 MB

Flash Drive Small, portable solid

state memory card that plugs into a USB port on your computer and functions as a portable hard drive.

Fits in your pocket and can plug into any computer that has a USB drive.

Called thumb drives, jump drives, pen drives, key drives, tokens, or simply USB drives.

Magnetic Storage Recording of data

onto disks or tape by magnetizing particles of an oxide-based surface coating.

Fairly permanent type of storage that can be modified.

Digital Audio Tape (DAT) Type of magnetic tape that uses a

scheme called helical scan to record data.

DAT cartridge is slightly larger than a credit card in width and height and contains a magnetic tape that can hold from 2 to 24 gigabytes of data.

Supports data transfer rates of about 2 MB per second.

Like other types of tapes, DATs are sequential-access media.

Optical Storage

Means of recording data as light and dark spots on CD or DVD.

Laser beam inside the drive bounces off the disk and the sequences of pits and not-pits (Lands) is converted into ones and zeros of the data. Pits: Dark spots Lands: Lighter, non-spotted surface areas

CD-ROM Compact Disc Read Only

Memory Optical storage medium uses

laser technology to read data that is permanently stored on compact disks.

Capable of storing large amounts of data—up to 1GB, although the most common size is 650MB (megabytes).

Single CD-ROM has the storage capacity of 700 floppy disks, enough memory to store about 300,000 text pages.

CD-R and CD-RW CD-R

Compact Disc-Recordable Can only have its surface data changed

once at each spot. Can write multiple sessions to one disk

until it is full; then it is read only. Hold 700 MB of data.

CD-RW Compact Disk-ReWritable Laser beams can read, write, and erase;

can be used many times (must erase before rewriting).

DVD-ROM

Digital Versatile Disc-Read Only Memory, or Digital Video Disc-Read Only Memory

Reads data from CD’s; audio and data DVD’s; data or movie Cannot be used to write data to a disk.

Computer Software

Operating System Software

Master controller for all activities that take place within a computer; primary purpose is to help the computer system monitor itself in order to function efficiently.

Interacts with application software, device drivers, and hardware to manage a computer’s resources.

Ensures that input and output proceed in an orderly manner.

Platform

Underlying hardware and software of the computer system.

Two popular platforms PC Mac

Multitasking

Running more than one program at a time.

Making sure that the instructions and data from one area of memory don’t interfere with memory allocated for other programs.

GUI (Graphical User Interface) A type of user interface that features

on-screen objects, such as menus and icons, manipulated by a mouse.

Abbreviation is pronounced “gooey”.

Definitions

Program Set of detailed, step-by-step instructions

that tell a computer how to solve a problem or carry out a task.

Application Software Set of computer programs that help a

person carry out a task. Drive

A location on a network that is set aside for the collection of data.

Definitions Folder

The subdirectory or subdivision, of a drive that can contain files or other folders.

File A named collection of data that exists on a

storage medium. Menu

A list from which the user may select an operation to be performed.

Icon A small picture that represents something (a file,

directory, or action) in a graphical user interface.