SECONDARY STORAGE DEVICESSection I : Chapter No. 4

Hardwares of Personal Computers 2

What are Basic Hardware of a Personal Computer?1. Monitor 2. Motherboard 3. CPU (Microprocessor) 4. Primary storage (RAM) 5. Expansion cards 6. Power supply 7. Optical disc drive 8. Secondary storage (Hard

disk) 9. Keyboard 10. Mouse

Figure 1. Basic hardware of a PC. (Wikipedia, 2007a)

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Classification of Hardware

Input Devices

1

Processing Unit

2

Storage Devices

3

Output Devices

4

Figure 2. Classification of Hardware.

Key: Data flow

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What are Types of Storage Devices?

Storage DevicesStorage Devices

Primary StoragePrimary Storage Secondary StorageSecondary Storage

Read-Only MemoryRead-Only Memory(ROM)(ROM)

Random-Access MemoryRandom-Access Memory(RAM)(RAM)

Figure 3. Classification of storage devices.

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What is Secondary Storage?

Secondary storage is computer memory that is not directly

accessible to the CPU of a computer, requiring the use of

computer's input/output channels.

It is used to store data that is NOT in active use.

It is usually slower than primary storage but it always has higher

storage capacity.

It is non-volatile. Data remains unchanged even after switching off

the computer.

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Secondary Storage

3.5” Floppy Disk Data can be read or write Data capacity:

1.44 MB

Figure 4. A floppy disk.

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Secondary Storage

Hard Disk Data can be read or write Speed of disk rotation

usually 7200 rpm Data capacity :

80GB, 160GB, 250GB, 300GB etc

Figure 5. A Hard disk.

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Secondary Storage

CD-Rom CD-R CD-RW

Data can be Read only Read but write once

Read & write

Data capacity (MB)

650 650 650

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Secondary Storage

DVD

(Digital Versatile Disk or Digital Video Disk)

DVD-R/ DVD+R

DVD-RW/ DVD+RW

Data can be Read only Read but write once

Read & write

Data capacity (GB)

Single layer:

4.7

Double layer:8.5

Single layer:

4.7

Double layer:8.5

Single layer:

4.7

Double layer:8.5

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What are the Different Between CD and DVD?

A compact disc [sometimes spelled disk] (CD) is a small, portable, round

medium made of molded polymer for electronically recording, storing, and

playing back audio, video, text, and other information in digital form

DVD is an optical disc technology with a 4.7 gigabyte storage capacity on a

single-sided, one-layered disk, which is enough for a 133-minute movie.

DVDs can be single- or double-sided, and can have two layers on each side;

a double-sided, two-layered DVD will hold up to 17 gigabytes of video, audio,

or other information. This compares to 650 megabytes (.65 gigabyte) of

storage for a CD-ROM disk.

DVD was originally said to stand for digital video disc, and later for digital

versatile disc.

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Secondary Storage

Figure 6. A C-R disk.

Figure 7. A CD-RW disk.

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Secondary Storage

Figure 8. A DVD-R disk.

Figure 9. A DVD+RW disk.

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Secondary Storage

USB flash drives

They are flash memory data storage devices

integrated with a USB interface.

They are typically small, lightweight,

removable and rewritable.

Data capacity:

512MB, 1GB, 2GB, 4GB, 8 GB, 16GB etc

USB flash drives also are called thumb drives,

jump drives, pen drives, key drives, tokens, or

simply USB drives.Figure 10. An USB flash drive.

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Secondary Storage

Memory Cards

e.g. SD card, CF card, xD card,

Microdrive, Memory Stick

Data can be read or write

Data capacity:

512 MB, 1GB, 2GB, 4GB, 16GB etc

Figure 11. A SD card.

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Various Types of Memory Cards

SM Card SD Card CF Card

xD card Memory Stick MicrodriveFigure 12. Various types of memory cards.

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THANK YOU

Suhas SubramanianMangesh Tilve

Anita RajanUsha Sawant

Rachna AmarnaniShilpa Shinde