advanced diploma 1 backing storage. advanced diploma 2 aims understand how data is stored be able to...

Advanced DiplomaAdvanced Diploma 11

Advanced DiplomaAdvanced Diploma

Backing StorageBacking Storage


AimsAims

Understand how data is storedUnderstand how data is stored

Be able to use the binary system to represent ASCII characters

Discuss the different types of backing store and understanding the meaning of CD, CD-R etc


How is data stored?How is data stored?

Bits and bytes Bits and bytes – A computer only understands the numbers 0 or 1,true

or false, or whether a switch is on or off.– We call those 1s and 0s ‘bits’ – binary digits.– A byte (made up of 8 bits) is enough computer

memory to store a single character of data (e.g. the letter F).

– Half a byte is known as a nibble (made up of 4 bits)– Using the ASCII code, for instance, the letter F is 70

and has a bit pattern of 01000110.


How is data stored? Cont.How is data stored? Cont.ASCII for Capital ASCII for Capital

LettersLetters

6565 AA 7878 NN

6666 BB 7979 OO

6767 CC 8080 PP

6868 DD 8181 QQ

6969 EE 8282 RR

7070 FF 8383 SS

7171 GG 8484 TT

7272 HH 8585 UU

7373 II 8686 VV

7474 JJ 8787 WW

7575 KK 8888 XX

7676 LL 8989 YY

7777 MM 9090 ZZ

American Standard Code for Information Interchange (ask-ee) is a code which represents English characters as numbers. Each letter is assigned a number. For example, A = 65.

Most computers use ASCII codes. This makes it possible to transfer data from one computer to another by changing the ASCII code into a binary pattern.


How is data stored? Cont.How is data stored? Cont.DecimalDecimal

When we write numbers in the decimal system, we write them in columns. Each column is ten times bigger than the one before (right to left).

Tens of Tens of millionsmillions

millionsmillions 100000s100000s 10000s10000s 1000s1000s 100s100s 10s10s 1s1s

11 00 11 00

So 1010 is 1000 plus 10 = 1010.

Tens of Tens of millionsmillions

millionsmillions 100000s100000s 10000s10000s 1000s1000s 100s100s 10s10s 1s1s

11 11 00 11 00

11010 would be 10000 plus 1000 plus 10 = 11010.


How is data stored? Cont.How is data stored? Cont.

In the binary system, everything is based on 2s, not 10s, so each column is twice as big as the one before.

128s128s 64s64s 32s32s 16s16s 8s8s 4s4s 2s2s 1s1s

11 00 11 00

So 1010 in binary is 8 plus 2 = 10.

128s128s 64s64s 32s32s 16s16s 8s8s 4s4s 2s2s 1s1s

11 11 00 11 00

11010 would be 16 plus 8 plus 2 = 26.


You have agoYou have ago


How is data stored? Cont.How is data stored? Cont.

All computer data is stored in binary form.

This not only includes text, but images, sounds and movies as well.

The more complex the data, the more memory is used to store it.

This does not take up asmuch memory… …as this.


Data StorageData Storage

1 megabyte (MB) is 1,000 KB (220)1 gigabyte (GB) is 1,000 MB (230)1 terabyte (TB) is 1,000 GB (240).

Confusingly, 1KB is actually 1,024 bytes (210), not 1,000 as you might expect, which is same for 1MB (1,024 KB), 1GB (1,024 MB) and 1TB (1,024 GB), but most people think in multiples of 1,000.


Types of backing storageTypes of backing storageComputers need backing storage outside the CPU to store data and programs not currently in use.There are three main types of storage device:

– Those that store data by magnetizing a special material that coats the surface of a disk.

– Those that store data using optical technology to etch the data onto a plastic-coated metal disk. Laser beams are then passed over the surface to read the data.

– Flash drives use solid state technology and store data in a similar way to the BIOS chip.


Backing storageBacking storageThe hard disk of the computer stores the system information, programs and data that the computer uses every day.

Computer servers will use RAID (Redundant Array of Inexpensive Disks ) ) systems with many hard drives to provide huge capacity and safer storage. The drives can be mirrored so that data written to one of them is also written to others, so if one drive fails, the others just take over.


Backing storageBacking storage

Removable hard drives plug into the USB port and can be used for backup or transfer of data to another computer.


Backing StorageBacking Storage

There are two main types of optical storage: CD and DVD. They look exactly the same, but DVDs hold much more data than CDs and need different drives to read them.

CD-ROMs are read only – you can read data from them but can’t write more data to them.CD-Rs allow you to write data once, but you can’t write over it. CD-RWs allow you to write data and then record new data over it.DVD-Rs and RWs follow the same pattern.You need special software to write to CDs and DVDs – you cannot simply copy files to them.


ConclusionConclusion

We discussed how data is storedWe discussed how data is stored

How to use the binary system to represent ASCII characters

Discussed the different types of backing store and understanding the meaning of CD, CD-R etc

advanced diploma 1 backing storage. advanced diploma 2 aims understand how data is stored be able to...

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