INTRODUCTION TO COMPUTERS

INTRODUCTION TO COMPUTERS

ESSENTIAL INFORMATION ABOUT COMPUTERS

WHAT DOES A COMPUTER DO?

WHAT DOES A COMPUTER DO?Performs four basic operations:

InputProcessOutputStorage

These operations comprise the INFORMATION PROCESSING CYCLE:Changing data into useable information and storing it for future use. All computer processing requires data.

DATA is a collection of unprocessed items

INFORMATION PROCESSING

INFORMATION PROCESSINGPutting data in useable form is INFORMATION PROCESSING

The system or group of devices and procedures that changes data into a useable form is called an INFORMATION SYSTEM

Data that enters the system is known as INPUTData in useful information that leaves the system is known as

OUTPUT or processed informationSteps set up to make sure everything that should be done to the

data is called PROCESSING

PROCESSINGINPUT OUTPUT

1ST STEP --- INPUT1ST STEP --- INPUTData to be processed or RAW DATARaw data written on forms is known as SOURCE

DOCUMENTS

2ND STEP ---- PROCESSING

2ND STEP ---- PROCESSING

Calculating arithmetic, making comparisons (graphs & charts), sorting in desired order

Each step toward the desired result MUST be completed in a specific and correct order or desired results will not occur

3rd STEP --- OUTPUT3rd STEP --- OUTPUT

Information displayed to the user on the monitor or paper

Output can be stored on a storage device such as a diskette

COMPUTER HARDWARECOMPUTER HARDWARE

Equipment that makes up the computer hardware fit into five categories:

INPUT DEVICESPROCESSORAUXILIARY STORAGEMAIN MEMORYOUTPUT DEVICES

Setup remains same regardless of computer size

FIVE CATEGORIESFIVE CATEGORIES

INPUT DEVICES

OUTPUT DEVICES

AUXILIARY STORAGE

MAINMEMORY

PROCESSOR

INPUT DEVICESINPUT DEVICES

Used to feed data into the computerKeyboard – most commonMouse – selects, moves or draws items on screen

THE SYSTEM UNITTHE SYSTEM UNIT Computer system unit that receives and carries out the series of instructions known as

a PROGRAM The MOTHERBOARD, sometimes called the system board, is the main circuit board

of the system unit. The processor, memory and expansion slots are some of the electronic

components that are attached to the motherboard.The sound card and video card are adapter cards that enhance the system with

add-on products. All systems regardless of size have a PROCESSOR or CPU -central processing unit Processing circuits are in one piece known as an integrated circuit “chip”. Other “chips” support the work of the processor chip in a variety of ways.

MAIN MEMORY MAIN MEMORY Data/instructions processed by a computer do not remain on the

processor “chip”.Data/instructions are stored in memory chips.Memory consists of “chips” on a memory module that fits in a slot

on the motherboard

Groups of memory chips make up main memory or main storage.

Data being processed spends most of its time in memory.

MAIN MEMORY CONT’DMAIN MEMORY CONT’D

Data/instructions are stored as electronic impulses in specific locations in memory.

Memory is like a post office with mail boxesThese mailboxes have a number known as its

NUMERIC ADDRESS. A memory chip may be either RAM or ROM

memory.

MAIN MEMORY CONT’DMAIN MEMORY CONT’DRAM (Random Access Memory) is used as temporary

storage while processing is doneThis memory is “volatile” --- its contents are lost when the

computer is turned off. Amount of RAM is measured in units called “bytes”

One byte is amount of memory to store one character – typically in “kilo” (1,000), “mega” (million), or “giga”(billion) – 512Mg represents 512 million characters

ROM (Read only memory) holds data permanently “nonvolatile” – its contents are not lost when the computer is

turned off. Stores instructions to start computer and since it is “Read-Only”

new information cannot be added to this type of memory

STORAGE DEVICESSTORAGE DEVICES Auxiliary storage devices hold data outside the memory of the computer as long as the user

needs. Four common types of storage devices are:

Magnetic disks (two types – floppy and hard disks)Optical discs – CD-ROM, CD-R, CD-RW, DVD – written on and read by a laser Tape – primarily used for long-term storage and backupMiniature mobile storage media (USB flash drives)

Disks have to be FORMATTED (dividing the disk into “tracks” and “sectors” so the computer can locate the information on the disk)

A diskette is made of flexible, magnetic plastic and frequently referred to as a “floppy”. The diskette is 3.5” and holds 1.44Mg of data.

Recently CD’s have become a storage device for new computers that have CD “burners” which records or “burns” data onto round, 4.5” disks that hold 600Mg or more of data.

OUTPUT DEVICESOUTPUT DEVICESA computer MUST have at least one output deviceIt records, prints, or displays information into useable form.The most frequently used output devices are the Video

Display or Monitor and the Printer. Inkjet printersLaser printersSpeed of printers determined by number of ppm – pages per

minute

SYSTEM SOFTWARESYSTEM SOFTWAREHardware is the physical equipment parts of the

computer. There are steps to follow to process data entered into a

computer. These steps are known as a Program. Programs in general are known as Software.

Control the operations of computer equipmentThere are 3 basic categories of software:

Operating System SoftwareUtility Software Application Software

OPERATING SYSTEM SOFTWARE

OPERATING SYSTEM SOFTWAREConsists of programs necessary to keep the hardware

functioning.It sets up and maintains communication between the

processor, auxiliary storage, input devices, and output devices.

It controls copying of data and feeds data to the processor

When computer is turned on, the operating system is loaded from the auxiliary storage. This process is called “BOOTING”

Most operating systems have GUI (graphical user interface) or icon symbols to help user.

UTILITY SOFTWAREUTILITY SOFTWAREA Utility program is a program that performs

routine jobs. Usually part of the system’s software, but can be

bought separately with additional capabilities. Firewall software and Virus Protection softwareNorton’s Disk DoctorScandisk and Defragmenter (part of the system that is

used frequently to “clean” the hard drive and fix errors)

APPLICATION SOFTWAREAPPLICATION SOFTWAREPrograms designed to solve specific problems for the user. Application software are available for almost any task imaginable.

Computerized banking (Quicken, QuickBooks)Word Processing, spreadsheet, database programsGraphing programsDeskTop Publishing programs

Integrated software combines several of these into one programMicrosoft Office SuiteCorel WordPerfect Suite