Introduction to Computers

Lecture 1.1Doug Hogan, 2003-04

Penn State UniversityCMPSC 100 – Computer Fundamentals and

Applications

Questions?Questions on syllabus?

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Attributes of ComputersSpeedReliabilityAccuracyStorageCommunication

ApplicationsWord processingFinancial management ShoppingEmailEntertainmentMany more…

Components of a Computer

Central processing unit (CPU)MemoryInput devicesOutput devicesStorage devices

Central Processing Unit (CPU)

Basic job: handle processing of instructionsWhat’s an instruction?Two parts:Control Unit (CU) Arithmetic and Logic Unit (ALU)

The ALUBuilt up from digital logic gatesANDORNOTmost primitive level

MemoryHolds programs that are currently running and the data being used by those programs. Two categories:Read-only memory (ROM)

can only read dataRandom-access memory (RAM)

can read and write information

Memory: sizesbase unit: 1 bit = binary digit, 0 or 18 bits = 1 byte (B)1000 bytes ≈ 1 kilobyte (KB)1000 KB ≈ 1,000,000 B ≈ 1 megabyte (MB)1000 MB ≈ 1,000,000,000 B ≈ 1 gigabyte (GB)

MemoryRelated data organized into files

Storage DevicesFloppy disk 3.5 inches, 1.44 MB

Hard disk typically sizes in GB

Compact disc (CD) 650-700 MB CD-ROM: read-only memory CD-R: recordable CD-RW: rewritable

More Storage DevicesDigital Versitale/Video Disc (DVD)4.7 GBZip disks and tape drivesvaries

Input Devicesmousekeyboardscannercameramicrophone

Output Devicesmonitorcathode ray tube (CRT) liquid crystal display (LCD)printerspeakers

Hardware vs. SoftwareHardwareessentially, things you can touch input, output, storage devicesSoftwareessentially, what the computer knowsdata, 0s and 1sprograms

Software OverviewSystem softwareControls basic operations of computerThe operating system

manages memory, files, application software

File management tasks – deleting, etc.

Software OverviewApplication softwareNot essential to system runningEnables you to perform specific tasksEx:

Office softwareWeb browsersMedia playersGames

Keyboard

Keyboard SpecificsCapsLock and ShiftNumLock and numeric keypadEscEditing and navigation keys insert, delete, home, end, page up, page down

Function keysCtrl, AltPrintScreen

Mouse: operations & buttons

Click – left buttonClick and dragShift-click, Ctrl-clickDouble clickTriple clickRight clickScroll wheel