File Formats and Significant Properties

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File Formats and Significant Properties

• Manfred Thaller
• Universität zu Köln
• March 24th, 2009
• University at not of Cologne

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I What is (in) a format?

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An image
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An image
6 rows 5 columns
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5 rows 6 columns
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An image
1 ochre 0 red
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An image
1 blue 0 yellow
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An image
Store 1,1,1,1,1,1,0,0,0,1,1,1,0,1,1,1,1,0,1,1,1,1
,0,1,1,1,1,1,1,1
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An image
Store 1,1,1,1,1,1,0,0,0,1,1,1,0,1,1,1,1,0,1,1,1,1
,0,1,1,1,1,1,1,1
Uncompressed
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An image
Store 6,1,3,0,3,1,1,0,4,1,1,0,4,1,1,0,7,1
(Compressed)Run Length Encoded
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An image
6 rows 5 columns 1 ochre 0
red Uncompressed
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An image
dimensions 1 ochre 0 red Uncompressed
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An image
dimensions photogrammetric interpretation Uncomp
ressed
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An image
dimensions photogrammetric interpretation compre
ssion
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An image
ltbasic informationgt ltrendering
informationgt ltstorage informationgt
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File format
ltbasic informationgt What to do? ltrendering
informationgt How to do it? ltstorage
informationgt How to move it from persistent
to deployed form? ltdatagt What to deploy?
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File format
ltbasic informationgt Mandatory ltrendering
informationgt Useful ltstorage informationgt
Historical ltdatagt Mandatory
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File format
A deterministic specification how the properties
of a digital object can reversibly be converted
into a linear bytestream (bitstream).
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II Why would we want to know?

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Bit rot
An Image file before .
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Bit rot
Undetectable by software.
... and after one byte is changed.
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Bit rot
Processing dictionary Payload
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Bit rot
One byte is damaged, one byte cannot be displayed
correctly.
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Bit rot
One byte is damaged, ten bytes cannot be
displayed correctly.
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But 1 Why should I care? Can I not just pay a
technician to keep some system of
checksums? Counter-but 1 Do you rather buy a
brand of car with a reputation of an excellent
network of maintenance shops, or one with a
reputation for needing little maintenance?
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But 2 But is bit rot really that important? I
have read, that files most of the time get either
unreadable completely, or stay completely
undamaged? Counter-but 2a In disaster
recovery yes! With files on degrading storage
systems / devices no!
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But 2 But is bit rot really that important?
Counter-but 2b Bit rot is, indeed, just one
problem.! We do this is just to show, that there
are differences between the technical fitness for
preservation between formats. Others go beyond 15
minutes.
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But 3 But is there not a simple list in this
type of problems, which I can consult
easily? Counter-but 3 No.
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III Which format to choose?

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Recommended formats text
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf
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Recommended formats bitmap / raster image
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf
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Recommended formats vector graphics
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf
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Recommended formats audio
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf
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Recommended formats video
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf
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Recommended formats data base
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf
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Recommended formats 3D (virtual reality)
http//www.fcla.edu/digitalArchive/pdfs/recFormats
.pdf

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Thank you!

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Exercise
ltformat 1gt   Size 1 - Count 1 - Shoot Some
ltxxxgt are not correctly displayed Some ltxxxgt are
not recognized   Size 1 - Count 1 -
Corrupt Unable to open the file File size has
changed   Size 512 - Count 1 - Shoot ltxxxgt are
not displayed   ltformat 2gt     Our findings
support / do not support the Florida recommendatio
ns for this type of content, because
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