Download - The Computer System2007
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