vga hardisk

8/6/2019 VGA HARDISK

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VGA

This is circuit board

that plug into the

computer

internally

internally &

connects to themonitor.

Its function is to

create the



PERFORMANCE

CHARACTERISTICS

Available resolution. Number of colour per pixels.

Video memory the card needto maintain the image inmemory.

speed in carring out a variety of different graphic functions.



LIQUID CRYSTAL

DISPLAYSThe screen

contains a layer

of liquid crystal

cells.

These have

unusual property

of hanging the

polarization of



CR T(crystal relay tube)

The electronic are produce byan electron gun & other

components allow the beam tobe deflected left and right & up

and down.



The processes used to

produce a display with

liquid crystals is as

follows.

a fluorescent panel generates light behind the

display panel

the light is filtered through a polariser.

Varying electrical charges are applied to

selected cells as required by the image,the

molecules in these liquid crystals cells

change shape and force the light to twist

(change polarisation)

the light emerging then passes through one of

three colour filters. Red,Blue, or Green that

are arranged close to each other.

The final colour displayed on the LCD monitor

depends upon the amount of twist of the light as

it passed through each of the filters.



HARD-DISK



+$5'',6.

Is one of secondary Storage

device(non-volatile),medium and as therepository for a user's documents, filesand applications.



Hard disks are rigid

platters, composedof a substrate and a

magnetic medium. The

substrate - theplatter's base

material - must be

non-magnetic andcapable of being

machined to a smooth

finish. It is made

CONSTRUCTION



FILE SYSTEM

The precise manner in which data is organized on a hard disk drive is determined by the file

system used. File systems are generally operating system dependent. However, since it is the

most widely used PC operating system, most other operating systems' file systems are at leastread-compatible with Microsoft Windows.



The FAT file system was first introduced in

the days of MS-DOS way back in 1981. Thepurpose of the File Allocation Table is to

provide the mapping between clusters - the

basic unit of logical storage on a disk at the

operating system level - and the physical

location of data in terms of cylinders, tracksand sectors - the form of addressing used

by the drive's hardware controller.



The FAT contains an

entry for every file

stored on the volume

that contains the

address of the file's

starting cluster. Eachcluster contains a

pointer to the next

cluster in the file, or an

end-of-file indicator at

(0x FFFF), which indicates

that this cluster is the

end of the file. The



FAT16, FAT32 and NTFS

each use differentcluster sizes

depending on the size

of the volume, and

each file system has a

maximum number of

clusters it can

support. The smaller

the cluster size, the

more efficiently a disk

stores information



The table below

provides a comparison

of volume and defaultcluster sizes for the

different Windows file

systems still

commonly in use:



PERFORMANCE

The performance of a

hard disk is very

important to the

overall speed of the

system - a slow harddisk having the

potential to hinder a

fast processor like noother system

component - and the

effective speed of a

vga hardisk

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