system storage,hard disk,flash drives,hard disk drives,storage devices

3. Presented by
Muhammad Jawad Zafar (group leader)
Aiza
Ahsan
Laraib
Muqaddas
Saba
Minhal
Tooba
Mahjamal
Rabia

5. Introduction
 Storage holds data instructions and information for future
use.
Types:
 There are two types of storage
 Primary storage
This stores data during computer operations. For example,
 RAM (Static RAM, Dynamic RAM)
 ROM (PROM, EPROM, EEPROM)
 Processor registers (Programme register, Address register,
Accumulative register, Storage register)
 Processor cache

6. Secondary storage
This stores data permanently. For example,
 Hard disc,
 USB Flash,
 Optical Discs,
 Memory Cards.

7. Storage Devices
 These are hardware components used to store data
instructions and information permanently.
 They are non-volatile.
Examples: Hard disc, USB flash, Optical disc, smart
cards, Magnetic strip etc.

8.  Capacity: it is the number of bytes (characters) a
storage medium can hold.
Examples:
 USB flash drive store upto 4GB.
 Hard disc store upto 320GB.
 Writing: it is a process of transferring data
instructions and information from memory to storage
medium.
 Reading: it is a process of transferring items from
storage medium into memory.

9.  Access time: it is the time taken by the storage device
to locate items on storage medium.
 Access time of storage device is low as compared to the
access time of memory
 Speed of storage device is defined by access time.

10. Hard Disc
 Hard disc is a storage devise that contain one or more
inflexible circular platters that use magnetic particles
to store data.
 A system unit contain at least one hard disc.
 Current PC’s have storage capacity of 160GB to 2TB.

11. Characteristics of Hard disc:
 Capacity
 Platter
 Read/write heads
 Cylinders
 Sectors and tracks
 Revolution per minute
 Transfer rate
 Access time

12. Longitudinal recording:
In longitudinal recording magnetic particles are
aligned horizontally around the surface of disc.
Perpendicular recording:
in perpendicular recording magnetic particles are
aligned vertically to the disc surface. Which make
storage capacity.
Storage capacity in perpendicular recording is 10 times
greater than longitudinal recording

13. Working of Hard Disc
 Step 1: The circuit board controls the movement of the
head actuator and a small motor.
 Step 2: A small motor spins the platters while the
computer is running.
 Step 3: when software request a disc access the
read/write heads determinate the current or new
location of data.
 Step 4: The head actuator positions the read/write
head arms over the correct location on the platters to
read or write data.

15. Types:
 Fixed Hard disc: A hard disc that is mounted inside the
system unit.
 Portable Hard disc: A hard disc that can be removed from
one computed and can be placed in other computer.
 External hard disc: It is separate free standing hard disc
that connects with a cable to USB port on system SU. Its
storage capacity is upto 4TB or more.
 Removable Hard disc: It is a hard disc that can be
inserted and removed from a drive. They have storage
capacity upto 1TB or more.

16. Miniature hard disc:
 Devices such as portable media players digital
cameras and smart phones have miniature hard disc
which provide greater storage capacity.
Storage range from 4GB to 250GB

17. Hard disk controller
 It is an electronic circuit that control the transfer of
data instructions and information.
 It controls the interface between the hard disc and
system bus.
 Types:
 SATA
 EIDE
 SCSI
 SAS

18.  SATA (serial advanced technology attachment)
 it uses serial signals to transfer data, instructions and
information.
 It has thinner, longer, more flexible, and less
susceptible cables than parallel signals.
 It can support connection to optical disc driver.
 External disc use “e SATA” intereface.

19.  EIDE (enhanced integrated drive electronics)
 It is hard disc interface.
 It uses parallel signals to transfer data instructions and
information.
 It support upto 137GB.
 It also provide connection for optical disc and tape
drives.

20.  SCSI (small computer system interface)
 It uses parallel signals to transfer data instructions and
information.
 It can support upto 8 or 15 peripheral devises.
 Some computer use an adopter card to add a SCSI
interface.
 SAS (statical analysis system)
 It is newer type of SCSI.
 It uses serial signals to transfer data.

21. Advantages of SAS over parallel SCSI
 It have thinner longer cables
 Reduce interface.
 Less expensive
 Support many devices at once

22. Flash Memory Storage
 It is a type of non-volatile storage.
 Data can be erased electronically and rewritten.
 Types:
 Solid State Drive:
It uses flash memory to store data, intructions and
information.
With available size of 3.5 inches, 2.5 inches and 1.8 inches.
 Advantages of SSD:
 Access time of SSD are about 0.1 ms.
 It is 80 time faster than hard disc.
 SSD generate less heat and consume less power than hard
disc.

23.  Memory Card:
 It is removable flash memory device.
 Usually not bigger than 1.5 inches.
 Types:
Compact Flash
Secure Digital
Micro SD
Memory Stick
Memory Stick Micro

25.  USB Flash Drive:
 It is also called thumb drive.
 It can be plug into the USB port of the computer.
 Storage capacity ranges from 512MB to 64GB
 Express Card Module:
 It is removable device.
 About 75mm long and 34mm wide or L shaped with
width of 54mm that fits in express card slot.
 It is commonly used in notebook computers

27. Cloud Storage
 Cloud storage is an internet service that provides hard
disc storage to the computer users.
 Fee arrangements vary
 For example: One cloud storage service provides 25 GB
of storage free to registered users.
 For enterprises, cloud storage charges 15 cents per GB.

29.  Variety of Reasons:
 To access files on internet
 To allow others to access their files on internet.
 To view time-critical data and images. For example
doctor can view x-ray images from an other hospital.
 To store offsite backups of data.

30. Optical Disc:
 Optical disc is a type of optical storage media that
consist of flat, round, portable disc made of metal,
plastic and lacqouer.
 Size ranges from4.75 inches in diameter and less than
1/20th of an inch thick.
 Optical disc store software, data, digital
photos, movies and music.

31.  Types of ODD:
CD Drive:
It is a device used by computer to read and write data
from or to a CD.
Types of CD Drive:
1. CD-ROM: Read data from CD
2. CD-R Drive: Read data from CD and can also write to
CD
3. CD-RW Drive: Read, write and rewrite

32.  DVD drive:
 Sands for digital versatile/video disc.
 It is used to store music, videos, games and multimedia.
 It is similar to CD in appearance.
 Its storage capacity is 7 times greater than CD.
 Blue-Ray drive:
 It is the name of next generation optical disc format.
 It enable us to record upto 25 GB.
 It is 6 times the capacity of DVD.
 Single layer BD can store upto 25 GB data and double can
store upto 50 GB data.

33.  Types:
BD ROM: (Read Only)
 For pre-recorded contents.
BD-R: (Recordable)
 For PC data storage.
BD-RW: (Re-writable)
 For PC data storage.
 BD-RE: (Re-writable)
 For HDTV recording.

34. Tape
 One of the first storage media used with main frame
computer
 Tape:
 It is magnetically coated with ribbon of plastic capable of
storing large amount of data.
 Tape drive:
 Tape drive read and write data and information on tape.
 Tape cartridge:
 It is a small rectangular plastic housing of tape.
 Tape Library:
 On larger computers tape cartridge are mounted in
separate cabinet called tape library.

35. Magnetic strip cards and smart
cards
Magnetic Stripe Card:
It is a credit card, bank card, entertainment card or other
similar cards. With a strip that contain information
identifying you and the card.
Information stored in the strip include your name, account
number and expiration date.
 Smart Cards:
It is smaller in size to the credit card or ATM card.
It stores data on thin microprocessor embedded in the card
Smart card can double as an ID card.

36.  Uses of Smart Card :
 Storing medical record
 Vaccination data
 Tracking information
 Storing Prepaid amount of money
 Authenticating users.

37. Microfilm and Microfiche
 They both can store microscopic images of documents
on roll or sheet films
 Microfilm is 100 to 215 foot roll of film.
 Microfiche is small sheet of film about 4×6 inches.
 Uses:
 Use in library
 Large organizations
 Banks
 US Army for personal records.

38. Advantages:
 They reduce the amount of paper.
 They have longest life of any storage media

39. Enterprise Storage
 A large business refer as enterprise has thousands of
employs working all over the world.
 They use computer network to manage their data
(includes huge volume of information about employs,
customers and suppliers)
 They use hardware components for storage.
 one or more server has only work of providing storage
to connected users.
 Some systems have storage capacity of 185 TB