Computer Logic Distinction between analogue and discrete processes and quantities. Conversion of analogue quantities to digital form. Using sampling techniques. Storage units.

Digital Data Digital data is represented by 1s

and 0s 1 represents that the switch is on 0 represents that the switch is off Digital data (1s and 0s) is known as binary. A computer system only

understands digital data

Analogue Data

Analogue data is represented by analogue signals

An example of analogue data are sound waves from our voice

Analogue data must be converted to digital data for the computer to understand it.

Analogue to Digital Data ATD As we said before analogue

signals need to be changed to digital data to be understood by our computer.

ATD devices convert analogue signals to digital data

Digital Data to Analogue Signals DTA For us to understand computer

language the digital data needs to be converted to analogue data

DTA devices convert digital data to analogue signals, ex: modem

Dear John,Is it OK if we meet at 6?

10010010

ISPISP

10010101Dear John,

Is it OK if we meet at 6?

Comparing Analogue to Digital devices

Analogue device Digital device

Continuous signalVarying valuesValues not rounded upDifficult for precise

reading

Not a continuous signal

Values rounded up Easy and clear to

readBecoming more

precise

Analogue and Digital Graphs

Analogue graph Digital graph

Changing an Analogue graph to a Digital graph is called Sampling

Units of Storage

A computer has many different units of storage

The storage units we will be going through today are;

Bits Bytes Kilobytes Megabytes Gigabytes Terabyte s

Each storage unit is made up of a number of bits

BitA bit is the smallest unit of

storage within a computer

A bit can only store a 1 or a 0

A bit is too small to store anything, hence they are joined to create other larger storage units. 1 Bit

Byte A byte is made up of 8 bits

One character is made up of 8 bits, hence 1 byte can hold 1 character.

To store the word byte you would need 4 bytes

1 Byte8 Bits

Kilobytes Bytes are still very small to store

many files so a larger storage unit is used, a Kilobyte

1024 bytes are grouped together to create a kilobyte

1 KiloByte

1024 Bytes

Units of Storage

Unit Equivalent

Bit (Can only store 0 or 1)

Byte 8 Bits

Kilobyte (KB) 1024 Bytes

Megabyte (MB) 1024 Kilobytes

Gigabyte (GB) 1024 Megabytes

Terabyte (TB) 1024 Gigabytes

Converting Units of Storage In order to convert small units to

large ones we need to divide

If we want to convert 7680 Bytes into KB (smaller to bigger unit);

1 KB = 1024 Bytes ? KB = 7680 Bytes 7680/1024=7.5KB

Converting Units of StorageIn order to convert large units to

smaller ones we need to multiply

If we want to convert 3MB into KB (bigger to smaller unit)

1 MB = 1024 KB 3 MB = ? KB

3 x 1024 = 3072 KB

More examples to work out Convert 4MB into kB

Convert 5890 Bytes into KB

Convert 2GB into KB

(round up your answers when needed. eg; 4.6 becomes 4)

AnswersConvert 4MB into kB

MB = 1024 KB4MB = ? KB

4 x 1024 = 4096MB

AnswersConvert 5890 Bytes into KB

1024 bytes = 1 KB5890 bytes = ? KB

5890/1024 = 6KB

AnswersConvert 2GB into KB

1 GB = 1024 MB 2 GB = ? MB

1 MB = 1024 KB2048MB = ? KB

If I want to know how many bytes there are in 2GB what would my next step be?

2 x 1024 = 2048MB

2048 x 1024 = 2097152KB

Some typical storage devices

Device Storage Other Possibilities

Floppy Disk 1.44MBCD 700MBDVD 4.7GB 8.7GB, 9.4GBPen Drive 8GB 2GB, 4GB,

16GB, 32GBBlu Ray 25GB 50GB, 100GBHard Disk 500GB 1TB

Home – Work

Handout 02 (form3opt1.blogspot.com)