This document provides an overview of primary and secondary storage. It discusses various types of secondary storage devices including magnetic storage devices like tapes, floppy disks, and hard disks which use magnetically coated surfaces. Optical storage devices are also covered, specifically CDs, DVDs, and Blu-ray discs which use reflected light to represent binary data. The document concludes with a brief description of solid state storage using integrated circuits.
2. Storage
Primary storage
Volatile
Temporary
It loses all its contents
when power to the system
unit is switched off.
Secondary storage
Nonvolatile
Permanent
Writing : is the
process of saving
information.
Reading: is the
process of accessing
information.
MBA/Kujur/SSD
5. MAGNETIC STORAGE
DEVICES
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The surface of the magnetic tape, floppy disk and
hard disc are all coated with a magnetically sensitive
material (iron oxide) which reacts to the magnetic
field.
Magnetic Tapes
Floppy Disks
Hard Disks
6. MAGNETIC TAPE
Sequentially accessed and processed
Plastic ribbon, ½ inch wide & 50-2400 ft long
Horizontal rows called tracks or channels
Magnetised - 1s & Non-magnetised – 0s
Magnetic material – Iron oxide/ Chromium dioxide
MBA/Kujur/SSD
Tracks
7. FLOPPY DISCS
MBA/Kujur/SSD
Flexible plastic disk inside a diskette cover
Disc divided into concentric circles called tracks
Tracks are divided into sectors
3.5 Inch Disc
8. Hard Disc
Use thicker, metallic platters for storage
Cylindrical storage mechanism
Large in capacity
Sensitive instrument – Read/ Write Head
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9. Internal Hard Disk
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•Located inside
system unit/ CPU
cabinet
•Known as a fixed
disk
•Designated as the
C drive with partition
as C:, D:, E:
•Advantage:
•High access
speedSolid State Drive
10. EXTERNAL HARD DISK
Removable hard disks
Used to complement internal hard
disk
Capacities of over 500 GB – 1 TB
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11. HARD DISK PACKS
Removable storage
Massive storage capacity
Common in mainframes
Used in Banks and bigger
organizations.
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12. Optical Disks
Compact
Permanent storage
Optical disk use reflected light.
The 1s and 0s are represented by pits & non-
pits.
Two common types
CD ( 650 MB to 1GB)
DVD ( 4.7 GB to 17 GB)
BRD (25 GB to 50 GB)
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13. Compact Disc
Optical format
From 650 MB to 1 GB capacity
Types
Read only: CD-ROM
Write once: CD-R
Rewriteable: CD-RW
Picture CDs and Photo CDs
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14. Digital Versatile Disk or Digital Video Disk
(DVD)
Similar to CDs, but can store more data
Types
Read only
Write once
Rewritable
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Digital Versatile Disk
15. Solid State Storage
Solid-state storage using integrated
circuits
Variable storage in terra bytes (TB)
Also called flash drives
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