File Types and Sizes

8/2/2019 File Types and Sizes

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The unit measurement storage in computerscience is byte.

How much is 1 byte, 1 kilobyte, 1 megabyte, 1gigabyte and 1 terabyte?

Does kilo in KB really mean 1000?


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1 yottabyte (YB) = 1024 zettabytes (ZB), 10248 bytes 1 ZB = 1024 exabytes (EB), 10247 bytes 1 EB = 1024 petabtyes (PB), 10246 bytes 1 PB = 1024 TB, 10245 btyes 1TB = 1024 GB, 10244 bytes 1GB = 1024 MB, 10243 bytes 1MB = 1024 kB, 10242 bytes 1 kB = 1024 byte 1B* = 8 bits (b)


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Therefore, 1B = 8b;

1 TB = 1024 GB 1000 GB

In computer science, for this matter, we do NOT goaccording to the SI units


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Normal numerals we use (0-9) are according to theDecimal Numeral System

It has 10 as its base

You cannot associate this to DNS in computerscience as DNS means Domain Name System, notDecimal Numeral System

SI Units are derived based on this system


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Using this system, KB is not accurate to describe thestorage capacity

We would have

Byte

Kibibyte (KiB) Mebibyte (MiB) Gibibyte (GiB) Tebibyte (TiB)

Pebibytes (PiB) Exbibtye (EiB) Zebibyte (ZiB) Yobibyte (YiB)


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JEDEC Standard 100B.01defines the prefix to unitsof semiconductor storage capacity

This derives the kilobyte, megabyte, gigabyte andso on


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Expressed in bytes

Increases with the number of pixels composing animage and the colour depth of the pixels

Image resolution is defined by the number of rowsand columns


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8 bit pixel stores 256 colours

24 bit pixel stores 16 million colours, known as atruecolour


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Standardised means of organizing and storingimages

File types eg. gif, jpeg, tiff, png, bmp


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Joint Photographic Experts Group Mostly are lossy format Used as the image compression algorithm in many

Adobe PDF files

Most digital camera can save photos under thisformat

Supports 8 bits per color (red, green, blue) for a 24-bit total - produces relatively small files


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Compression of image's quality is not noticeableunless file is repeatedly edited and saved

It will then suffer generational degradation

Photographic images may be better stored in alossless non-JPEG format if they will be re-edited

and will not be so pixelated


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Exchangeable image file

Incorporated in JPEG software used in mostcameras to record and standardise the exchangeof data between digital cameras and editing andviewing software


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Data recorded for individual images includes such things like: Camera settings Time and date Shutter speed Exposure Image size Compression Name of camera Color information etc

When images are viewed or edited by image editors, all theabove information can be displayed


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Tagged Image File Format

Flexible format that normally saves 8 bits or 16 bitsper color (red, green, blue) for 24-bit and 48-bit

TIFF formats are lossy and lossless

Some offer relatively good lossless compression forbi-level (black & white) images


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Some digital cameras can save in TIFF format forlossless storage

Not widely supported by web browsers

Remains widely accepted as a photograph filestandard in the printing business


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Can handle device-specific colour spaces, such asthe CMYK defined by a particular set of printingpress inks

OCR (Optical Character Recognition) softwarepackages commonly generate some (often

monochromatic) form of TIFF image for scanned

text pages


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Refers to a family of raw image formats that areoptions available on some digital cameras

Usually uses a lossless compression to produce filesizes much smaller than the TIFF formats of full-sizeprocessed images from the same camera

Not standardised or documented


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Not accepted by many graphic programs andimage editors

Can be standardised using Adobe's DigitalNegative


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Portable Network Graphics

Free open-source successor to the GIF

Supports truecolor while the GIF supports only 256 colours

Excels when the image has large, uniformly coloured areas

Lossless PNG format is best suited for editing pictures


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Lossy PNG formats are best for the final distribution ofphotographic images, just like JPG

However JPG files are smaller than PNG files

Many older browsers currently do not support PNG file format

With Internet Explorer 7, all contemporary web browsers nowsupport all common uses of PNG format, including full 8-bittranslucency


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Internet Explorer 7 may display odd colors on translucentimages ONLY when combined with IE's opacity filter

PNG provides a patent-free replacement for GIF and canalso replace many common uses of TIFF

Indexed-color, grayscale, and truecolor images aresupported, plus an optional alpha channel


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PNG is designed to work well in online viewing applications

Fully streamable with a progressive display option

Provides both full file integrity checking and simple detectionof common transmission errors

PNG can store gamma and chromaticity data for improvedcolor matching on platforms with multiple layers


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Graphics Interchange Format

Limited to an 8-bit palette, or 256 colors

Makes GIF format suitable for storing graphics withrelatively few colors such as simple diagrams,shapes, logos and cartoon style images


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Supports animation and is still widely used toprovide image animation effects

Uses a lossless compression that is more effectivewhen large areas have a single color, andineffective for detailed images


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Windows Bitmap Handles graphics files within the Microsoft Windows

OS

Typically uncompressed

Large sized Simple, widely accepted, and use in Windows

programs


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Computer Graphics Metafile

For 2D vector graphics, raster graphics, and text

All graphical elements can be specified in a textualsource file

Can be compiled into a binary file of one or twotext representations


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Independent from any particular application,system, platform, or device

Used in areas of technical illustration andprofessional design

Largely superseded by formats such as SVG andDXF


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Scalable Vector Graphics Versatile, scriptable and all-purpose vector format

for the web and otherwise

Does not have a compression scheme of its own

Can be compressed using a program such as gzip Because of its scripting potential, SVG is a key

component in web applications


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Shockwave Flash

Intended to be small enough for publication on theweb

Contain applets of varying degrees of interactivityand function

Functions as the dominant format for displaying"animated" vector graphics on the Web


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Windows Metafile

A graphics file format on Microsoft Windowssystems

Intended to be portable between applicationsand may contain both vector and bitmap

components

WMF is a 16-bit format introduced in Windows 3.0


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A newer 32-bit version with additional commands iscalled Enhanced Metafile (EMF)

Used as a graphics language for printer drivers

There are also compressed versions of WindowsMetafiles known as Compressed Windows Metafile

(WMZ) & Compressed Windows Enhanced Metafile(EMZ)

File Types and Sizes

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