LessonStorageDevices Short Ver

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TEE COURSE GRADE10

MODULE 7 - PC HARDWARE

Memory and Storage Devices


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LEARNING OBJECTIVES

At the end of this lesson, students will be able to :1. Meet the expectations of the Course Curriculum coded as:

TFV.01E, TF2.01E, TF2.02E, TF2.03E, TF2.04E, IC1.02E,SPV.01E;

2. Explain the function and interaction of the primary (RAM, ROM)and secondary storage devices (magnetic and optical);

3. Describe secondary storage devices: FDD, HD, CD-ROM, DVD;

4. Use precise terminology in relation to all storage devices;

5. Explain how data is stored on the surface of magnetic andoptical disks;

6. Uninstall and re-install main and secondary storage devices:RAM, FDD, HD, CD-ROM;

7. Use safe practices in the handling of computer hardware and

electronic components.


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Computer System Components

Central Processing Unit

Output

Devices

Cache

Memory

Primary

Storage

SecondaryStorageDevices

ControlUnit

ALU

Special

Purpose

Processors

Output

DevicesInput

Devices

Short Review

Communication Devices


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Three levels of memory hierarchy

Principle: the closer the memory is to the CPU, the faster it is.


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Memory addresses

Memory is a collection ofcells, each with a unique

physical/memory address

Each cell can hold one

byte or 8 bits

101 102 103

201

301

202 203

302 303

With one by we can represent

one character in ASCII Code

Example: A is 65 in ASCII

code and 01000001 in binary

representation


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Application/Thinking

How many bytes are in the phrase You aregreat! .

a) 11b) 13

c) 14

d) 1So, this sentence will occupy __?__ cells in

memory


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Storage Capacity

Unit------------kilobyte

megabytegigabyteterabytepetabyteexabyte

Exact Number of bytes------------------------

210 bytes220 bytes230 bytes240 bytes250 bytes260 bytes

Approx imat ion------------103 bytes

106 bytes

109 bytes

1012 bytes

1015 bytes

1018 bytes


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Application/Thinking

How many megabytes (MB = 2 to the power

of 20 bytes) are in a terabyte (1TB = 2 to

the power of 40 bytes):

a) 2 to the power of 10

b) 2 to the power of 20

c) 2 to the power of 40

d) 2 to the power of 80


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PRIMARY MEMORY: RAM AND ROMRAM (Random Access Memory) is volatile (temporary).

Programs and data can be written to and erased from RAMas needed. This means that RAM does not retain its bit

configuration when the power is turned off, but ROM does

ROM ( Read Only Memory) is nonvolatile (permanent). Thecontents in locations in ROM cannot be changed

It holds instructions that run the computer when it is

first turned on (BIOS)

The CPU accesses each location in memory by using a

unique number, called a memory address.


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Memory types- RAM

RAM: random access memory

SRAM: static RAM

No need to be refreshed

DRAM: dynamic RAM

Need to be refreshed periodically

Main memory

SDRAM (Synchronous DRAM)

EDRAM (Enhanced DRAM)

EDO (Extended Data Out)

FLASH RAM

Ferroelectric RAM


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Memory types ROM

ROM: read-only memory (Pre-programmed)

PROM: programmable ROM

Only written once

EPROM: erasable PROM

Use ultraviolet light to erase data

EEPROM: electronically EPROM Can be erased using electronic impulses (higher

voltages)


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Secondary Storage Devices

Storage devices hold data, even when thecomputer is turned off.

The physical material that actually holds data is

called a storage medium. The surface of a floppy

disk is a storage medium.

The hardware that writes data to or reads data

from a storage medium is called a storage

device. A floppy disk drive is a storage device.

The two primary storage technologies are

magnetic and optical.


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Magnetic StorageDevices

Diskettes (floppy disks) (FDD)

Hard disks (HD)

High-capacity floppy disks (ZIP Disk)

USB flash drive

Magnetic tape


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Optical Storage Devices

Compact Disk Read-Only Memory (CD-ROM)

Digital Video Disk Read-Only Memory

(DVD-ROM)

CD-Recordable (CD-R)

CD-Rewritable (CD-RW)

PhotoCD


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CLASSIFICATION- BIG PICTURE

Memory Types &

Storage Devices

Primary

Secondary

Volatile

Registers

Cache (I, II, III)

RAM

SRAMDRAM

SDRAMEDRAMEDOFLASH RAM

Non-volatileROM

PROM

EPROM

EEPROM

Magnetic memoryTapeHD, Zip DiskFDD

Optical

Memory

CD-ROM, CD-R, CD-RWDVD-ROM, DVD-R

DVD- RW

(Semiconductor

chip). Main Memory

(Devices)

2ns

5ms


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Magnetic Storage Devices

- How Magnetic Storage Works

A magnetic disk's medium contains iron

particles, which can be polarizedgiven a

magnetic chargein one of two directions

(north or south).

Each particle's direction represents a 1 (on) or 0

(off), representing each bit of data that the CPU

can recognize.

A disk drive uses read/write heads containing

electromagnets to create magnetic charges on

the medium.


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As the medium

rotates, the head

writes the data.


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Magnetic Storage Devices - Diskettes

Diskette drives, also known as floppy disk drives,read and write to diskettes (called floppy disks or

floppies).

In disks the areas to save data are organized as aset of concentric circles called Tracks. Floppy disks

have 80 tracks. The disks are further divided into

pie-slice Sectors.

300 rpm

Diskettes size: 3.5-inch.


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Formatted Disk


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3.5 inch

floppy

and drive


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Hard Disk Drive Purpose:

Long-term, nonvolatile storage Large, inexpensive, slow level in the storage

hierarchy

Disk compositionA magnetic disk consist of a collection of platters

(1to 20 per disk) that rotate on a spindle.

Disk surface divided into tracks (1000 to 4800 per

platter).

Tracks are divided into sectors (64 per track), which

are the smallest unit that can be read or written.

Up to 10,000 rpm


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Magnetic Disks A read/write head travels across a spinning magnetic

disk, retrieving or recording data

The organization

of a magnetic disk


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Optical Storage Devices

How Optical Storage Works

An optical disk is a high-capacity storage

medium. An optical drive uses reflected light to

read data.

To store data, the disk's metal surface is

covered with tiny dents (pits) and flat spots

(lands), which cause light to be reflected

differently.

When an optical drive shines light into a pit, the

light cannot be reflected back. This represents a

bit value of 0 (off). A land reflects light back to

its source, representing a bit value of 1 (on).


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1 0


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Optical storage devices

CD-ROM: compact disc ROM (Read Only Memory)

Capacity: 650MB

CD-R: compact disc recordable

CD-RW: compact disc rewritable

DVD: digital versatile disc

Capacity: 4.7GB 17GB

DVD-R

DVD-RW (2 versions: + (plus) and

(dash)


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DVD (Digital Versatile Disk)

Allows up to 17 gigabytes of storage (from 4.7GB to 17 GB).

Compatible with older CD-ROM technology.

The four versions of the DVD:


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lesson Review

List four types of magnetic and four types of optical

storage devices.

Identify two common uses for floppy disks.

Explain how data is stored on the surface of magneticand optical disks.

List three variations on optical disk technology.


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EVALUATION

1. Cache memory has the fastest speed: T F2. A TB has 1024 MB? T F

3. EPROM is a volatile memory? T F

4. SRAM needs to be refreshed? T F

5. EEPROM use ultraviolet light to erase data?T F

6. A land reflects light back to its source,

representing a bit value of 1 (on). T F

7. A pit, does not reflect the light back and thisrepresents a bit value of 0 (off). T F


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EVALUATION SHORT TEST conted8. Define the following acronyms:

SRAM ______________________________ DRAM ______________________________

SDRAM ______________________________

EDRAM ______________________________

PROM ______________________________ EPROM ______________________________

EEPROM ______________________________

CD-ROM ______________________________

HDD ______________________________

FDD ______________________________

DVD RW ______________________________

CD-RW ______________________________

Documents

LessonStorageDevices Short Ver