Download - Presentation on computer data storage
A PRESENTATION ON COMPUTER DATA STORAGE -
PRIMARY & SECONDARY MEMORY
By Ayush Garg
1. Primary Memory2. Secondary Memory3. Summary4. Questions & Answers5. Thank You
Flow of the Presentation
Primary Memory…1. Only one directly accessible to the CPU.2. Used to hold the temporarily data during the
execution.3. Other names are – Main Memory or Internal
Memory4. Types of Primary memory–
1. RAM – Random Access Memory2. ROM – Read Only Memory3. PROM/EPROM - Programmable ROM
5. It has a Limited Capacity6. Information is retained only when it is Actively
Rehearsed.
Primary Memory…
EPROM
ROM
RAM
sSecondary Memory . . .
1. Secondary Memory also known as EXTERNAL MEMORY or AUXILIARY MEMORY.
2. Often formatted according to a File Systems Format.
3. Provide abstraction necessary to organize data into files and directories.
4. Also Providing Additional Information METADATA describing the owner of the certain file.
Random Access Storage Devices
Allows Stored Data to Be Accessed Quickly In Any Random OrderIt Has Taken The Form Of Integrated Circuits It is Associated With Volatile Types Of Memory Where The Stored Data Is LOST If The Power Is REMOVED Any Location In The Device Can Be Selected At Random, Access To The Information Stored Is DIRECT
A Class Of Data Storage Device It Reads the Data In Sequence Very Much In Contrast With RAM (where Data Can Be Accessed In Any Order) They Are Usually A Form Of Magnetic Devices Access Can STILL Be Made To Arbitrary Locations Typically Used For Secondary Storage It Has High Density And Cost As Compared To RAM As Well As Resistance to Wear and Non-Volatility EXAMPLE – Hard Disks, CD- ROMS And Magnetic Tapes
Sequential Access Storage Devices
HARD DISKS
PERFORMANCE ENHANCEMENTS
OPTICAL DISKS
SPECIALISED MEDIA
FLOPPY DISKS
Types Of SASD
Portable And Removable
Flat Circular Mylar Media
Magnetic Charge on Metal Oxide Film Coating
Standard 2 HD 1.44 MB
Parts
Tracks Sectors
Floppy Disks
Floppy disk cartridgesZip Disks
250 MBSuper Disks
120 MBHiFD disks
200 MB
High Capacity Floppy Disks
Metallic disksFast retrieval, greater capacityRead/write heads ride cushion of
air .000001” thickThree types
Internal hard diskHard-disk cartridgeHard-disk pack
Hard Disks
No Entry
Inside system unitNon-removable or portableGreat capacity
Over 100 GigabytesFast access speed
Internal Hard Disks
HARD DISK CARTRIDGESPortable,
removableComplement
internal hard driveJAZ from Iomega SPARQ from
SyQuestPC Card Hard
DisksLaptop
computers
HARD DISK PACKSUsed in mainframesRemovable
Resemble stack of vinyl records
Multiple read/write heads
Massive storage capacity
Fast access time
Performance Enhancements
Improving performance of hard disksDisk caching Redundant Arrays of Inexpensive Disks
(RAID)File compression and decompression
Very large capacityUp to 17 gigabytes
Use reflected light projected by a laser
Lands and Pits represent 1’s and 0’s
FormatsCompact Disk (CD)Digital Versatile
Disk (DVD)Data Play
Optical Disks
Widely used format today
Can store from 650 MB to 1 GB
Rotational speed = data transfer time
Types of CDsCD-ROMCD-RCD-RW
Compact Disks
Digital Versatile Disk
Rapidly replacing CDs Higher capacity17 times the
capacity of a CD
DVD
DVD typesDVD-ROM
Read only memoryDVD-R
RecordableDVD-RAM or DVD-RW
Competing rewritable formats
DVD Types
DATA PLAYOptical write-once
formatSimilar to CD-RSize of a quarterUsed for special
applicationsStoring digital
photographsStoring music for
portable players
MAGNETIC TAPESequential accessCommonly used for backing-up
dataVery large capacityTypes of magnetic tape
Tape cartridgesMagnetic tape reels
Tape cartridgesBackup tape for microcomputer Capacities range from 120 MB to 5
GBDigital audio tape (DAT)
Tape reelsMinicomputer and mainframe1/2 inch wide and 1/2 mile longStores 1600 to 6400 cpi
Internet hard driveFree or low-cost storage on the WebAccess information from any locationAccess time is greater
Solid-state storageNo moving partsFlash memory cards
Internet Hard Drives &
Solid States
A Look To The FutureBlue laser light optical
devicesAimed more
accuratelyCan increase storage
capacity to 27 GB per standard optical disk
New players will likely play both
Questions & Answers
THANK YOU