Computer fundamentals computer application characteristics generation uses

Computer fundamentals

1. BBS COLLAGE OF ENGINEERING AND
TECHNOLOGY
UNIT –01
BCA SECTION “B”
COMUTER FUNDAMENTALS

2. •Acomputerisaprogrammableelectronicdevicethataccepts
rawdataasinputandprocessesitwithasetofinstructions(a
program)toproducetheresultasoutput.
•Itrendersoutputjustafterperformingmathematicaland
logicaloperationsandcansavetheoutputforfutureuse.
•Itcanprocessnumericalaswellasnon-numerical
calculations.Theterm"computer"isderivedfromtheLatin
word"computare"whichmeanstocalculate.
WHAT IS COMPUTER?

3. WHAT IS COMPUTER?
•ItisbelievedthattheAnalytical
Enginewasthefirstcomputer
whichwasinventedbyCharles
Babbagein1837.
•Itusedpunchcardsasread-only
memory.CharlesBabbageisalso
knownasthefatherofthe
computer.

4. BASIC PART OF A COMPUTER
•Thebasicpartswithoutwhichacomputercannotworkareas
follows:
•Processor:Itexecutesinstructionsfromsoftwareand
hardware.
•Memory:Itistheprimarymemoryfordatatransferbetween
theCPUandstorage.
•Motherboard:Itisthepartthatconnectsallotherpartsor
componentsofacomputer.

5. BASIC PART OF A COMPUTER
•StorageDevice:Itpermanentlystoresthedata,e.g.,hard
drive.
•InputDevice:Itallowsyoutocommunicatewiththe
computerortoinputdata,e.g.,akeyboard.
•OutputDevice:Itenablesyoutoseetheoutput,e.g.,
monitor.

6. CHARACTERISTICS OF THE COMPUTER

7. SPEED
•Acomputerworkswithmuchhigherspeedandaccuracy
comparedtohumanswhileperformingmathematical
calculations.
•Computerscanprocessmillions(1,000,000)ofinstructions
persecond.
•Thetimetakenbycomputersfortheiroperationsis
microsecondsandnanoseconds.

8. ACCURACY
•Computersperformcalculationswith100%accuracy.Errors
mayoccurduetodatainconsistencyorinaccuracy.

9. DILIGENCE
•Acomputercanperformmillionsoftasksorcalculationswith
thesameconsistencyandaccuracy.
•Itdoesn’tfeelanyfatigueorlackofconcentration.
•Itsmemoryalsomakesitsuperiortothatofhumanbeings.

10. VERSATILITY
•Versatilityreferstothecapabilityofacomputertoperform
differentkindsofworkswithsameaccuracyandefficiency

11. RELIABILITY
•Acomputerisreliableasitgivesconsistentresultforsimilar
setofdatai.e.,ifwegivesamesetofinputanynumberof
times,wewillgetthesameresult.

12. AUTOMATION
•Computerperformsallthetasksautomaticallyi.e.itperforms
taskswithoutmanualintervention.

13. MEMORY
•Acomputerhasbuilt-inmemorycalledprimarymemory
whereitstoresdata.Secondarystorageareremovable
devicessuchasCDs,pendrives,etc.,whicharealsousedto
storedata.

14. BLOCK DIAGRAM OF COMPUTER

15. INPUT
•Allthedatareceivedbythecomputergoesthroughtheinput
unit.Theinputunitcomprisesdifferentdeviceslikeamouse,
keyboard,scanner,etc.
•Inotherwords,eachofthesedevicesactsasamediator
betweentheusersandthecomputer.
•Thedatathatistobeprocessedisputthroughtheinputunit.
Thecomputeracceptstherawdatainbinaryform.
•Itthenprocessesthedataandproducesthedesiredoutput.

16. INPUT
The3majorfunctionsoftheinputunitare-
•Takethedatatobeprocessedbytheuser.
•Convertthegivendataintomachine-readableform.
•Andthen,transmittheconverteddataintothemainmemory
ofthecomputer.Thesolepurposeistoconnecttheuserand
thecomputer.Inaddition,thiscreateseasycommunication
betweenthem.

17. CPU –CENTRAL PROCESSING UNIT
•CentralProcessingUnitortheCPU,isthebrainofthe
computer.
•Itworksthesamewayahumanbrainworks.Asthebrain
controlsallhumanactivities,similarlytheCPUcontrolsallthe
tasks.
•Moreover,theCPUconductsallthearithmeticalandlogical
operationsinthecomputer.
•NowtheCPUcomprisesoftwounits,namely–ALU
(ArithmeticLogicUnit)andCU(ControlUnit).
•Bothoftheseunitsworkinsync.TheCPUprocessesthedata
asawhole.

18. ALU–ARITHMETIC LOGIC UNIT
•TheArithmeticLogicUnitismadeoftwoterms,arithmetic
andlogic.Therearetwoprimaryfunctionsthatthisunit
performs.
•Dataisinsertedthroughtheinputunitintotheprimary
memory.
•Performsthebasicarithmeticaloperationsonit,likeaddition,
subtraction,multiplication,anddivision.
•Itperformsallsortsofcalculationsrequiredonthedata.
Then,itsendsbackdatatothestorage.
•Theunitisalsoresponsibleforperforminglogicaloperations
likeAND,OR,Equalto,Lessthan,etc.

19. CU –CONTROL UNIT
•Thecontrolunitasthenamesuggestsisthecontrollerofall
theactivities/tasksandoperations.
•Allthisisperformedinsidethecomputer.
•Thememoryunitsendsasetofinstructionstothecontrol
unit.
•Thenthecontrolunitinturnconvertsthoseinstructions.After
thattheseinstructionsareconvertedtocontrolsignals.
Thesecontrolsignalshelpinprioritizingandscheduling
activities.Thus,thecontrolunitcoordinatesthetasksinside
thecomputerinsyncwiththeinputandoutputunits.

20. MEMORY UNIT
•Allthedatathathastobeprocessedorhasbeenprocessedis
storedinthememoryunit.
•Thememoryunitactsasahubofallthedata.Ittransmitsit
totherequiredpartofthecomputerwhenevernecessary.
•ThememoryunitworksinsyncwiththeCPU.Thishelpsin
fasteraccessingandprocessingofthedata.Thus,making
taskseasierandquicker.

21. TYPES OF COMPUTERS
•

22. SUPER COMPUTER

23. SUPER COMPUTER
•Supercomputersarethebiggestandfastestcomputers.
•Theyaredesignedtoprocesshugeamountofdata.
•Asupercomputercanprocesstrillionsofinstructionsina
second.
•Ithasthousandsofinterconnectedprocessors.
•Supercomputersareparticularlyusedinscientificand
engineeringapplicationssuchasweatherforecasting,
scientificsimulationsandnuclearenergyresearch.
•ThefirstsupercomputerwasdevelopedbyRogerCrayin
1976.

24. FEATURES OF SUPERCOMPUTERS
•Ithastheabilitytodecryptyourpasswordtoenhance
protectionforsecurityreasons.
•Itproducesexcellentresultsinanimations.
•Itisusedforvirtualtestingofnuclearweaponsandcritical
medicaltests.
•Itcanstudyandunderstandclimatepatternsandforecast
weatherconditions.ItcanruninNOAA'ssystem(National
OceanicandAtmosphericAdministration)thatcanexecute
anytypeofsimpleandlogicaldata.
•Ithelpsindesigningtheflightsimulatorsforpilotsatthe
beginnerlevelfortheirtraining.

25. MAINFRAME COMPUTER
•Mainframe computers are designed to support hundreds or
thousands of users simultaneously.
•They can support multiple programs at the same time.
•It means they can execute different processes simultaneously.
•These features of mainframe computers make them ideal for
big organizations like banking and telecom sectors, which
need to manage and process high volume of data.

26. FEATURES OF MAINFRAME COMPUTER
•Itcanprocesshugeamountofdata,e.g.millionsof
transactionsinasecondinthebankingsector.
•Ithasaverylonglife.Itcanrunsmoothlyforupto50years
afterproperinstallation.
•Itgivesexcellentperformancewithlargescalememory
management.
•Ithastheabilitytoshareordistributeitsworkloadamong
otherprocessorsandinput/outputterminals.
•Ithastheabilitytoprotectthestoreddataandotherongoing
exchangeofinformationanddata.
•

27. MINIFRAME OR MINICOMPUTER
•Itisamidsizemultiprocessingcomputer.Itconsistsoftwoor
moreprocessorsandcansupport4to200usersatonetime.
•Miniframecomputersareusedininstitutesanddepartments
fortaskssuchasbilling,accountingandinventory
management.
•Aminicomputerliesbetweenthemainframeand
microcomputerasitissmallerthanmainframebutlargerthan
amicrocomputer.

28. FEATURES OF A MINICOMPUTER
•It is light weight that makes it easy to carry and fit anywhere.
•It is less expensive than mainframe computers.
•It is very fast compared to its size.
•It remains charged for a long time.
•It does not require a controlled operational environment.

29. MICROCOMPUTER
•Microcomputerisalsoknownasapersonalcomputer.
•Itisageneral-purposecomputerthatisdesignedfor
individualuse.
•Ithasamicroprocessorasacentralprocessingunit,memory,
storagearea,inputunitandoutputunit.
•Laptopsanddesktopcomputersareexamplesof
microcomputers.
•Theyaresuitableforpersonalworkthatmaybemakingan
assignment,watchingamovie,oratofficeforofficework.

30. FEATURES OF A MICROCOMPUTER
•Itisthesmallestinsizeamongalltypesofcomputers.
•Alimitednumberofsoftwarecanbeused.
•Itisdesignedforpersonalworkandapplications.Onlyone
usercanworkatatime.
•Itislessexpansiveandeasytouse.
•Itdoesnotrequiretheusertohavespecialskillsortrainingto
useit.
•Generally,comeswithsinglesemiconductorchip.
•Itiscapableofmultitaskingsuchasprinting,scanning,
browsing,watchingvideos,etc.

31. WHAT IS PROGRAMMING LANGAUAGE?
•Aprogramminglanguageisacomputerlanguagethatisused
byprogrammers(developers)tocommunicatewith
computers.
•Itisasetofinstructionswritteninanyspecificlanguage(C,
C++,Java,Python)toperformaspecifictask.
•Aprogramminglanguageismainlyusedtodevelopdesktop
applications,websites,andmobileapplications.

32. TYPES OF PROGRAMMING LANGUAGES

33. LOW LEVEL LANGUAGES
•Low-levellanguageismachine-dependent(0sand
1s)programminglanguage.
•Theprocessorrunslow-levelprogramsdirectlywithoutthe
needofacompilerorinterpreter,sotheprogramswrittenin
low-levellanguagecanberunveryfast.
•Low-level language is further divided into two parts -
•i. Machine Language
ii. Assembly Language

34. MACHINE LANGUAGES
•Machinelanguageisatypeoflow-levelprogramming
language.
•Itisalsocalledasmachinecodeorobjectcode.Machine
languageiseasiertoreadbecauseitisnormallydisplayedin
binaryorhexadecimalform(base16)form.
•Itdoesnotrequireatranslatortoconverttheprograms
becausecomputersdirectlyunderstandthemachinelanguage
programs.
•Theadvantageofmachinelanguageisthatithelpsthe
programmertoexecutetheprogramsfasterthanthehigh-
levelprogramminglanguage.

35. ASSEMBLY LANGUAGE
•Assemblylanguage(ASM)isalsoatypeoflow-level
programminglanguagethatisdesignedforspecific
processors.
•Itrepresentsthesetofinstructionsinasymbolicandhuman-
understandableform.
•Itusesanassemblertoconverttheassemblylanguageto
machinelanguage.
•Theadvantageofassemblylanguageisthatitrequiresless
memoryandlessexecutiontimetoexecuteaprogram.

36. HIGH-LEVEL PROGRAMMING LANGUAGE
•High-levelprogramminglanguage(HLL)isdesigned
fordevelopinguser-friendlysoftwareprogramsand
websites.
•Thisprogramminglanguagerequiresacompilerorinterpreter
totranslatetheprogramintomachinelanguage(executethe
program).
•Themainadvantageofahigh-levellanguageisthatitiseasy
toread,write,andmaintain.
•High-levelprogramminglanguageincludesPython,Java,
JavaScript,PHP,C#,C++,ObjectiveC,Cobol,Perl,Pascal,
LISP,FORTRAN,andSwiftprogramminglanguage.

37. DATA ORGANIZATION
•Dataorganizationisthewaytoarrangetherawdatainan
understandableorder.
•Organizingdataincludeclassification,frequencydistribution
table,picturerepresentation,graphicalrepresentation,etc.

38. DRIVE
•Diskdrive(drive)–acomputerdevicethatstoresand
retrievesinformation,data,files,programs,etc.,fromadisk.
•Thedriveisoftenreferredtobyitsletter(yourdriveletter
maydiffer).
•Aharddiskdrive(harddiskorfixeddisk)isusuallydesignated
asthe“C:drive”.

39. DRIVE
•Adriveisalocation(medium)thatcanstoreandread
informationthatisnoteasilyremoved,likeadiskordisc.
•Alldrivesstorefilesandprogramsusedbyyourcomputer.For
example,whenyouwritealetterinawordprocessor,the
programisloadedfromtheharddrive.
•Whenyousavethedocument,it'ssavedtotheharddriveor
otherdiskordrive.
•ThepictureshowsdifferentdriveslistedinMicrosoft
WindowsMyComputer.
•Some users may confuse a "drive" with a "driver." These are
separate terms. If you need help with installing or
updatingsoftwarerelated to hardware, see ourdriverpage.

40. DRIVE
•Inthepicture,driveA:isthefloppy
drive,C:istheprimaryharddrive,
D:andE:arepartitions,andF:is
theCD-ROMdrive.
•TheCD-ROMdriveisusuallythe
lastdriveletter.Inmostsituations,
theharddriveistheC:drive,anda
CD-ROMorotherdiscdriveisthe
D:drive.

41. FILE
•Afileacontainerinacomputersystemthatstoresdata,
information,settings,orcommands,whichareusedwitha
computerprogram.
•Ingraphicaluserinterface(GUI),suchasMicrosoftoperating
systems,representthefilesasicons,whichassociatetothe
programthatopensthefile.
•Forinstance,thepictureisshownasanicon;itisrelated
toMicrosoftWord.
•Ifyourcomputercontainsthisfileandyoudouble-clickonthe
icon,itwillopeninMicrosoftWordinstalledonthecomputer.

42. FILE
•Thereareseveraltypesoffilesavailablesuchasdirectoryfiles,datafiles,
textfiles,binaryandgraphicfiles,andtheseseveralkindsoffilescontain
differenttypesofinformation.
•Inthecomputersystem,filesarestoredonharddrives,opticaldrives,
discs,orotherstoragedevices.
•Thebasicoperationsthatcanbeperformedonafilearegivenbelow:
•Closing or terminating a file operation
•Creation of programs
•Reading of data from the file
•Creation of a new file
•Opening the file in order to make the contents available to other
•Modification of data or file attributes
•Writing data to the file

43. DIRECTORY
•Adirectoryisalocationforstoringfilesonyourcomputer.
Directoriesarefoundinahierarchicalfilesystem,such
asLinux,MS-DOS,OS/2,andUnix.
•PicturedisanexampleofoutputfromtheWindows/DOStree
command.Itshowsallthelocalandsubdirectories(e.g.,the
"big"directoryinthe"cdn"directory).Lookingatthis
overview,thecurrentdirectoryistherootdirectoryoftheC:
drive.It'scalledthe"root"directorybecausethereisnothing
beneathit,andtheotherdirectories"branch"fromit.Ifyou
usesanoperatingsystemwithmultipleuseraccounts,the
directorymayalsobecalledahomedirectory.
•

44. DIRECTORY

45. MEMORY MANAGEMENT
•Computermemoryisjustlikethehumanbrain.Itisusedto
storedata/informationandinstructions.
•Itisadatastorageunitoradatastoragedevicewheredatais
tobeprocessedandinstructionsrequiredforprocessingare
stored.
•Itcanstoreboththeinputandoutputcanbestoredhere.
•

46. CHARACTERISTICS OF COMPUTER MEMORY
•It is faster computer memory as compared to secondary
memory.
•It issemiconductormemories.
•It is usually a volatile memory, and main memory of the
computer.
•A computer system cannot run without primary memory.

47. TYPES OF COMPUTER MEMORY

48. PRIMARY MEMORY
•Itisalsoknownasthemainmemoryofthecomputersystem.
Itisusedtostoredataandprogramsor
instructionsduringcomputeroperations.
•Itusessemiconductortechnologyandhenceiscommonly
calledsemiconductormemory.Primarymemoryisoftwo
types:
•RAM
•ROM

49. RAM (RANDOM ACCESS MEMORY)
•It is a volatile memory.
•Volatile memory stores information based on the power
supply.
•If the power supply fails/ interrupted/stopped, all the data
and information on this memory will be lost.
•RAMis used for booting up or start the computer.
•It temporarily storesprograms/datawhich has to be executed
by theprocessor.
•RAM is of two types:
•SRAM
•DRAM

50. SRAM AND DRAM
•SRAM(StaticRAM):SRAMusestransistorsandthecircuits
ofthismemoryarecapableofretainingtheirstateaslongas
thepowerisapplied.
•Thismemoryconsistsofthenumberofflipflopswitheachflip
flopstoring1bit.
•Ithaslessaccesstimeandhence,itisfaster.
•DRAM(DynamicRAM):DRAMusescapacitorsand
transistorsandstoresthedataasachargeonthecapacitors.
•Theycontainthousandsofmemorycells.
•Itneedsrefreshingofchargeoncapacitorafterafew
milliseconds.
•ThismemoryisslowerthanSRAM.

51. ROM
•It is a non-volatile memory.
•Non-volatile memory stores information even when there is a
power supply failed/ interrupted/stopped.
•ROMis used to store information that is used to operate the
system.
•As its name refers to read-only memory, we can only read the
programs and data that is stored on it.
•It contains some electronic fuses that can be programmed for a
piece of specific information.
•The information stored in the ROM in binary format. It is also
known as permanent memory.
•ROM is of four types

52. FEATURES OF ROM
•FeaturesofROM
•ROMisanon-volatilememory.
•InformationstoredinROMispermanent.
•Informationandprogramsstoredonit,wecanonlyreadand
cannotmodified.
•InformationandprogramsarestoredonROMinbinary
format.
•Itisusedinthestart-upprocessofthecomputer.

53. TYPES OF READ-ONLY MEMORY
•MROM(Maskedread-onlymemory):
•WeknowthatROMisasoldassemiconductortechnology.
•MROMwastheveryfirstROMthatconsistsofagridofword
linesandbitlinesjoinedtogethertransistorswitches.
•ThistypeofROMdataisphysicallyencodedinthecircuitand
onlybeprogrammedduringfabrication.
•Itwasnotsoexpensive.

54. PROM
•PROM(Programmableread-onlymemory):
•PROMisaformofdigitalmemory.
•InthistypeofROM,eachbitislockedbyafuseoranti-fuse.
•Thedatastoredinitarepermanentlystoredandcannotbe
changedorerasable.
•Itisusedinlow-levelprogramssuchasfirmwareor
microcode.

55. EPROM
•EPROM(Erasableprogrammableread-onlymemory):
•EPROMalsocalledEROM,isatypeofPROMbutitcanbe
reprogrammed.
•ThedatastoredinEPROMcanbeerasedandreprogrammed
againbyultravioletlight.
•Reprogrammedofitislimited.
•BeforetheeraofEEPROMandflashmemory,EPROMwas
usedinmicrocontrollers.

56. EEPROM
•EEPROM(Electricallyerasableprogrammableread-only
memory):
•Asitsnamerefers,itcanbeprogrammedanderased
electrically.
•ThedataandprogramofthisROMcanbeerasedand
programmedabouttenthousandtimes.
•ThedurationoferasingandprogrammingoftheEEPROMis
nearabout4msto10ms.
•Itisusedinmicrocontrollersandremotekeylesssystems.
•

57. ADVANTAGES OF ROM
•It is cheaper thanRAMand it is non-volatile memory.
•It is more reliable as compared to RAM.
•Its circuit is simple as compared to RAM.
•It doesn’t need refreshing time because it is static.
•It is easy to test.

58. DISADVANTAGES OF ROM
•It is a read-only memory, so it cannot be modified.
•It is slower as compared to RAM.

59. DIFFERENCE BETWEEN RAM AND ROM
RAM ROM
RAM stands for Random Access Memory. ROM stands for Read Only Memory.
You can modify , edit or erase data in RAM.
Data in ROM can not modified or erased, you can only
read data of ROM.
RAM is a volatile memory that stores data as long as
power supply is given.
ROM is a non-volatile memory that retiandata even
after the power is turned off.
Speed of RAM is more then speed of ROM. ROM is slower then RAM.
RAM is costly as compared to ROM. ROM is cheap as compared to RAM.
A RAM chip can store only a few gigabytes (GB) of
data.
A ROM chip can store multiple megabytes (MB) of
data.
CPU can easily access data stored in RAM. CPU cannot easily access data stored in ROM.
RAM is used for the temporary storage of data
currently being processed by the CPU.
ROM is used to store firmware, BIOS, and other data
that needs to be retained.

60. SECONDARY STORAGE DEVICES
•Asecondarystoragedevicereferstoanynon-volatilestorage
devicethatisinternalorexternaltothecomputer.
•Itcanbeanystoragedevicebeyondtheprimarystoragethat
enablespermanentdatastorage.
•Asecondarystoragedeviceisalsoknownasanauxiliary
storagedevice,backupstoragedevice,tier2storage,or
externalstorage.
•Thesedevicesstorevirtuallyallprogramsandapplicationson
acomputer,includingtheoperatingsystem,devicedrivers,
applicationsandgeneraluserdata.

61. WHY DO WE NEED SECONDARY STORAGE?
•Computersusemainmemorysuchasrandomaccessmemory(RAM)and
cachetoholddatathatisbeingprocessed.
•However,thistypeofmemoryisvolatile,anditlosesitsdatawhenthe
computerisswitchedoff.
•General-purposecomputers,suchaspersonalcomputersandtablets,
needtostoreprogramsanddataforlateruse.
•That'swhysecondarystorageisneededtokeepprogramsanddatalong
term.
•Secondarystorageisnon-volatileandabletokeepdataaslongterm
storage.
•Theyareusedforvariouspurposessuchasbackupdatausedforfuture
restoresordisasterrecovery,long-termarchivingofdatathatisnot
frequentlyaccessed,andstorageofnon-criticaldatainlower-performing,
lessexpensivedrives.
•

62. CHARACTERISTICS OF SECONDARY STORAGE DEVICES
Thesearesomecharacteristicsofsecondarymemory,which
distinguishitfromprimarymemory,suchas:
•Itisnon-volatile,whichmeansitretainsdatawhenpoweris
switchedoff
•Itallowsforthestorageofdatarangingfromafewmegabytes
topetabytes.
•Itischeaperascomparedtoprimarymemory.
•SecondarystoragedeviceslikeCDsandflashdrivescan
transferthedatafromonedevicetoanother

63. TYPES OF SECONDARY STORAGE
DEVICE

64. FIXED STORAGE
•Fixedstorageisaninternalmediadeviceusedbyacomputer
systemtostoredata.
•Usually,thesearereferredtoasthefixeddiskdrivesorHardDrives.
•Fixedstoragedevicesarenotfixed.
•Thesecanberemovedfromthesystemforrepairingwork,
maintenancepurposes,andalsoforanupgrade,etc.
•Butingeneral,thiscannotbedonewithoutapropertoolkitto
openupthecomputersystemtoprovidephysicalaccess,which
needstobedonebyanengineer.
•Technically,almostalldata,i.e.beingprocessedonacomputer
system,isstoredonsomebuilt-infixedstoragedevice.

65. FIXED STORAGE
•We have the following types of fixed storage:
•Internal flash memory (rare)
•SSD (solid-state disk) units
•Hard disk drives (HDD)

66. REMOVABLE STORAGE
•Removablestorageisanexternalmediadevicethatisusedby
acomputersystemtostoredata.
•Usually,thesearereferredtoastheRemovableDisksdrivesor
theExternalDrives.
•Removablestorageisanystoragedevicethatcanberemoved
fromacomputersystemwhilethesystemisrunning.
•ExamplesofexternaldevicesincludeCDs,DVDs,Blu-raydisk
drives,anddiskettesandUSBdrives.
•Removablestoragemakesiteasierforausertotransferdata
fromonecomputersystemtoanother.

67. REMOVABLE STORAGE
•Themainbenefitofremovabledisksinstoragefactorsisthat
theycanprovidethefastdatatransferratesassociatedwith
storageareanetworks(SANs).Wehavethefollowingtypesof
RemovableStorage:
•Opticaldiscs(CDs,DVDs,Blu-raydiscs)
•Memorycards
•Floppydisks
•Magnetictapes
•Diskpacks
•Paperstorage(punchedtapes,punchedcards)

68. FLOPPY DISK
•A floppy disk is a flexible disk with a magnetic coating on it,
and it is packaged inside a protective plastic envelope.
•These are among the oldest portable storage devices that
could store up to 1.44 MB of data, but now they are not used
due to very little memory storage.

69. HARD DISK DRIVE (HDD)
•Harddiskdrivecomprisesaseriesofcirculardisks
calledplattersarrangedoneovertheotheralmost½inchesapart
aroundaspindle.
•Disksaremadeofnon-magneticmateriallikealuminiumalloyand
coatedwith10-20nmmagneticmaterial.
•Thestandarddiameterofthesedisksis14inches,andtheyrotatewith
speedsvaryingfrom4200rpm(rotationsperminute)forpersonal
computersto15000rpmforservers.
•Dataisstoredbymagnetizingordemagnetizingthemagneticcoating.
•Amagneticreaderarmisusedtoreaddatafromandwritedatatothe
disks.
•AtypicalmodernHDDhasacapacityinterabytes(TB).

70. HARD DISK DRIVE

71. CD DRIVE
•CD stands for Compact Disk.
•CDs are circular disks that use optical rays, usually lasers, to
read and write data.
•They are very cheap as you can get 700 MB of storage space
for less than a dollar.
•CDs are inserted in CD drives built into the CPU cabinet. They
are portable as you can eject the drive, remove the CD and
carry it with you.

72. CD DRIVE
•TherearethreetypesofCDs:
–CD-ROM(CompactDisk-ReadOnlyMemory):The
manufacturerrecordedthedataontheseCDs.Proprietary
Software,audioorvideoarereleasedonCD-ROMs.
–CD-R(CompactDisk-Recordable):Theusercanwrite
dataonceontheCD-R.Itcannotbedeletedormodified
later.
–CD-RW(CompactDisk-Rewritable):Datacanrepeatedly
bewrittenanddeletedontheseopticaldisks.

73. PEN DRIVE
•ApendrivealsoknownasaUSBflashdrive,isadatastorage
devicethatincludesflashmemorywithanintegratedUSB
interface.
•AtypicalUSBdriveisremovable,rewritable,andsmallerthan
anopticaldisc,andusuallyweighslessthan30g.
•Apendriveisasmallyetpowerfuldevicethatcanhelpyou
transferfilesbetweendeviceseasilyandquickly.
•Ithasrevolutionizedhowwestoreandtransferdata.

74. DIFFERENCE BETWEEN PRIMARY AND
SECONDARY MEMORY
Primary Memory Secondary Memory
Primary memory is directly accessed by the
Central Processing Unit (CPU).
Secondary memory is not accessed
directly by the Central Processing Unit
(CPU). Instead, data accessed from a
secondary memory is first loaded into
Random Access Memory (RAM) and
then sent to the Processing Unit.
RAM provides a much faster-accessing speed
to data than secondary memory. Computers
can quickly process data by loading software
programs and required files into primary
memory (RAM).
Secondary memory is slower in data
accessing. Typically primary memory is
six times faster than secondary
memory.
Primary memory is volatile and gets
completely erased when a computer is shut
down.
Secondary memory provides a feature
of being non-volatile, which means it
can hold on to its data with or without
an electrical power supply.

75. I/O DEVICES
•Aninput/outputdevice,oftenknownasanIOdevice,isany
hardwarethatallowsahumanoperatororothersystemsto
interfacewithacomputer.
•Input/outputdevices,asthenameimplies,arecapableof
deliveringdata(output)toandreceivingdatafroma
computer(input).
•Aninput/output(I/O)deviceisapieceofhardwarethatcan
take,output,orprocessdata.
•Itreceivesdataasinputandprovidesittoacomputer,aswell
assendscomputerdatatostoragemediaasastorageoutput.

76. SCANNER
•Ascannerisaninputdevicethatfunctionssimilarlytoa
photocopier.
•It’semployedwhenthere’sinformationonpaperthatneeds
tobetransferredtothecomputer’sharddiscforsubsequent
manipulation.
•Thescannercollectsimagesfromthesourceandconverts
themtoadigitalformatthatmaybesavedonadisc.
•Beforetheyareprinted,theseimagescanbemodified.

77. PLOTTERS
•Plotterisadevicethathelpsinmakinggraphicsorother
imagestogivearealview.
•Agraphiccardismandatorilyrequiredtousethesedevices.
•Thesearethepen-likedevicesthathelpingeneratingexact
designsonthecomputer.

78. LCD
•LCDstandsforLiquidCrystal
Display.
•Itisaflatpaneldisplaytechnology,
mainlyusedinTVsandcomputer
monitors,nowadaysitisusedfor
mobilephonesalso.
•TheseLCDsarecompletely
differentfromthatoldCRT
displays,itusesliquidcrystals
insteadofcathoderayinits
primaryformofoperation.

79. PLASMA DISPLAY
•Aplasmadisplayisatypeofflatpaneldisplaythatuses
plasma,anelectricallychargedionizedgas,toilluminateeach
pixelinordertoproduceadisplayoutput.
•ItiscommonlyusedinlargeTVdisplaysof30inchesand
higher.
•Plasma displays are often brighter than LCD displays and also
have a wider color gamut, with black levels almost equaling
“dark room” levels.

80. NUMBER SYSTEM
•Thelanguageweusetocommunicatewitheachotheriscomprised
ofwordsandcharacters.
•Weunderstandnumbers,charactersandwords.Butthistypeof
dataisnotsuitableforcomputers.Computersonlyunderstandthe
numbers.
•So,whenweenterdata,thedataisconvertedintoelectronicpulse.
•Eachpulseisidentifiedascodeandthecodeisconvertedinto
numericformatbyASCII.
•Itgiveseachnumber,characterandsymbolanumericvalue
(number)thatacomputerunderstands.
•Sotounderstandthelanguageofcomputers,onemustbefamiliar
withthenumbersystems.

81. NUMBER SYSTEM
The Number Systems used in computers are:
•Binary number system
•Octal number system
•Decimal number system
•Hexadecimal number system

82. BINARY NUMBER SYSTEM
•Ithasonlytwodigits'0'and'1'soitsbaseis2.
•Accordingly,Inthisnumbersystem,thereareonlytwotypes
ofelectronicpulses;absenceofelectronicpulsewhich
represents'0'andpresenceofelectronicpulsewhich
represents'1'.
•Eachdigitiscalledabit.Agroupoffourbits(1101)iscalleda
nibbleandgroupofeightbits(11001010)iscalledabyte.
•Thepositionofeachdigitinabinarynumberrepresentsa
specificpowerofthebase(2)ofthenumbersystem.

83. OCTAL NUMBER SYSTEM
•Ithaseightdigits(0,1,2,3,4,5,6,7)soitsbaseis8.
•Eachdigitinanoctalnumberrepresentsaspecificpowerof
itsbase(8).
•Asthereareonlyeightdigits,threebits(23=8)ofbinary
numbersystemcanconvertanyoctalnumberintobinary
number.
•Thisnumbersystemisalsousedtoshortenlongbinary
numbers.
•Thethreebinarydigitscanberepresentedwithasingleoctal
digit.

84. DECIMAL NUMBER SYSTEM
•Thisnumbersystemhastendigits(0,1,2,3,4,5,6,7,8,9)so
itsbaseis10.
•Inthisnumbersystem,themaximumvalueofadigitis9and
theminimumvalueofadigitis0.
•Thepositionofeachdigitindecimalnumberrepresentsa
specificpowerofthebase(10)ofthenumbersystem.
•Thisnumbersystemiswidelyusedinourdaytodaylife.
•Itcanrepresentanynumericvalue.

85. HEXADECIMAL NUMBER SYSTEM
•Thisnumbersystemhas16digitsthatrangesfrom0to9and
AtoF.So,itsbaseis16.
•TheAtoFalphabetsrepresent10to15decimalnumbers.
•Thepositionofeachdigitinahexadecimalnumberrepresents
aspecificpowerofbase(16)ofthenumbersystem.
•Asthereareonlysixteendigits,fourbits(24=16)ofbinary
numbersystemcanconvertanyhexadecimalnumberinto
binarynumber.
•Itisalsoknownasalphanumericnumbersystemasituses
bothnumericdigitsandalphabets.

86. NUMBER SYSTEM CONVERSION

87. DECIMAL TO BINARY NUMBER SYSTEM

88. DECIMAL TO OCTAL CONVERSION

89. DECIMAL TO HEXADECIMAL
CONVERSION

90. BINARY TO DECIMAL CONVERSION

91. BINARY TO HEXADECIMAL CONVERSION

92. BINARY TO OCTAL CONVERSION

93. BINARY ADDITION

94. BINARY ADDITION

95. BINARY SUBTRACTION

96. BINARY SUBTRACTION

97. BINARY MULTIPLICATION

98. BINARY MULTIPLICATION

99. THANK YOU