Computer memory and its types designed for students

Computer memory

1. K.M.S. SailajaRani
Lecturer in Computer Science
Y.A. Govt. College for Women
Chirala
by

2. •Computer is an electronic device used to store
and retrieve data to perform a particular task.
•Here the term retrieve means to get it again

3. Computer Memory is an internal storage area in
the computer, in which data and Programs are
stored either temporarily or permanently .

4. •Also known as Main
Memory or internal
memory.
•It holds instructions
and data, When a
program is executed.
•Volatile In Nature
•It Is Expensive And
Limited Storage
Capacity
•Non-Portable
•Data Access Is High
•Also known as Auxiliary
Memory or external
memory
•It holds data and
programs, that are not
currently in use and
provides long term
storage .
•Non-Volatile In Nature
•It Is Cheap And Stores
Voluminous Data
•Highly Portable
•Data Access is low When
Compared To Primary

5. Primary Memory Is The Only Type Of Memory, That Is
Directly Accessed by The CPU.
Memory usually refers to Random Access Memory (RAM),typically
DRAM.
Types Of Primary Memory Are:
1)Random Access Memory (RAM)
2)Read Only Memory (ROM)

6. •RandomAccessMemoryisa
volatilestorageareawithinthe
computerthatistypicallyusedto
storedatatemporarily.Sothatitcan
bepromptlyaccessedbythe
processor.
•TheinformationstoredintheRAM
isbasicallyloadedfromthe
computersharddisk,andincludes
datarelatedtotheoperatingsystem
andapplicationsthatarecurrently
beingexecutedbytheprocessor.
•RAMisconsideredrandomaccess
becauseanymemorycellcanbe
directlyaccessedifitsaddressis
known.
•Readonlymemoryreferscomputer
memorychipscontainingpermanent
orsemi-permanentdatawhichis
non-volatile.
•Mostcomputerscontainasmall
amountofROMthatcontainscritical
programssuchasthebasicinputand
outputsystem(BIOS),whichisused
tobootupthecomputerwhenitis
turnedon.
•ROMsarereadonly.Toupdatethe
programsstoredinthem,theROM
chiphadtoremovedandphysically
replacedbyanotherthathadnew
versionoftheprogram.Butintoday
ROMchipsupdationsarepossible.

7. Holdsdatawithoutanexternal
refreshaslongasitIspowered.
MadeupofDFlip-Flops,Inwhich
memorycellsFlip-FlopBetween0&1
withoutuseofcapacitors.
Occupiesmorespaceandexpensive.
SRAMisfasterandmorereliable.
SRAMchipsareusedincars,house
holdappliancesandhandheld
electronicdevices.
Commontypeofmemoryusedin
PC,workstations,servers.
Mustberefreshedinasecondto
holdit’sdatacontents.
It’schipcontainmillionsofmemory
cells.Eachcellismadeupof
transistorsandcapacitorsandcontains
1bitofinformation.
Itischeapandcanhold4Times
moredatathanSRAM.

8. ItisAlsoCalledOneTimeProgrammablePROM
AndCanBeWrittenOrProgrammedusingASpecial
DeviceCalledAPromProgrammer.
ItIsATypeOfRamThatCanBeerasedAnd
Reprogrammed.
ItIsBasedonASemi-ConductorStructureSimilar
ToTheEPROMButAllowsTheEntireOr
SelectedContentsToBeelectricallyErasedAnd
Re-WrittenElectrically,SoThatTheyNeedNot
BeRemovedFromTheComputer.Theprocessof
WritinganEEPROM isalsoknownas
FLASHING.
Rewritable ROM chips include PROM, EPROM,EEPROM