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INTRODUCTION TO TIME TRAVEL

-OR-

HOW TO SEND YOUR FILES TO THE FUTURE

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TIME TRAVEL: A MODIFIED DEFINITION

COMMUNICATION ACROSS TIME AND SPACE

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A BRIEF HISTORY OF TIME TRAVEL

RECENT ATTEMPTS AT TIME TRAVEL

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INFORMATION PRESERVATION

REQUIRES DIGITAL PRESERVATION

The Future!

A long time ago…

Today

Today

Analog

Digital

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WHAT DOES ‘DIGITAL’ ACTUALLY MEAN?

(FOR STORAGE)

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MAGNETIC MEDIA: HARD DRIVES

Peaks = 1sTroughs = 0s

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SOLID STATE MEDIA: SD CARDS

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OPTICAL MEDIA: CDS

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A QUESTION OF REPRESENTATION

“I am the wisest man alive, for I

know one thing, and that is that I know nothing.”

-Plato

00100010010010010010000001100001011011010010000001110100011010000110010100100000011101110110100101110011011001010111001101110100001000000110110101100001011011100010000001100001011011000110100101110110011001010010110000100000011001100110111101110010001000000100100100100000011010110110111001101111011101110010000001101111011011100110010100100000011101000110100001101001011011100110011100101100001000000110000101101110011001000010000001110100011010000110000101110100001000000110100101110011001000000111010001101000011000010111010000100000010010010010000001101011011011100110111101110111001000000110111001101111011101000110100001101001011011100110011100101110001000100000110100001010001011010101000001101100011000010111010001101111

= =

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"I am the wisest man"alive, fob I know one

thing, and that is that I onow nothing."

-Plato

“I am the wisest man alive, for I know one thing, and

that is that I know nothing.”

-Plato

BIT ROT: THE DEGRADATION OF BITS OVER TIME

3 Bits CorruptedOriginal Text

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BITLOSS

& DIGITALPHOTOS

Images from Melanie Willhide’s “to Adrian Rodreguez with love”http://www.vonlintel.com/Melanie-Willhide.html

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ALMOST LOST

NASA images from first Lunar Orbiter 1966

BBC Domesday Project 1986

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DOMESDAY PROJECT

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DIGITAL PRESERVATION STRATEGIES

1. Format Choice

2. Documentation

3. Migration

4. Emulation

5. Hashing/checksums

6. File Identification

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1. FORMAT CHOICE

Hardware

Software

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NDIIPP

http://www.digitalpreservation.gov/formats/index.shtml

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THE LIBRARY OF CONGRESS:DIGITAL PRESERVATION

http://www.digitalpreservation.gov/

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2. DOCUMENTATION & METADATA

• File Name• File Size• Number of Words• Total Editing Time• Creation Date• Last Modified• Last Printed• User Name

• File TypeWord Doc

• Software VersionMS Word 2010

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3. MIGRATION

• The transfer of a bit stream (the 1s and 0s) from one medium to another.

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FINDING THE HARDWARE

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MIGRATION

Similar to photocopying –including the imperfections.

Data can be lost or corrupted in the transfer.

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WRITE BLOCKERS

• Prevents inadvertently overwriting digital information.

• Allows ‘read’ commands to pass, blocks ‘write’ commands.

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4. EMULATIONCreates an environment that ‘tricks’ the software into functioning as if it was in its original computing environment.

Similar to impersonation.

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EMULATION & THE GAMING COMMUNITY

"The Old Version Flickers More": Digital Preservation from the User's Perspective

http://archivists.metapress.com/content/1765364485n41800/

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BROWSER BASED EMULATION

https://archive.org/details/historicalsoftware

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5. HASHING/CHECKSUMS

How they work:An algorithms ‘reads’ a digital object and, based upon the 1s and 0s that make up that object, produces a unique alpha-numeric string of characters that represent it.

What that means:Checksums are very effective tools in determining if a digital object has been corrupted (assuming you have the original checksum to compare it to).

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HASHING

461D5E8093B94401EAF12E442CEAB908

FD7D5993062D270F482E00BDE64D35FE

Original File

Corrupted File

MD5 Hash

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HASHING

http://download.cnet.com/MD5-SHA-Checksum-Utility/3000-2092_4-10911445.html

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HASHING IN TWO STEPS

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IDENTIFYING MYSTERY FILES

.hqx? .mkv? .ape?

You have to identify what a file is in order to figure out what software can render it. But how?

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6. FILE IDENTIFICATION

Step 1: Google the file extension

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IDENTIFYING MYSTERY FILES

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IDENTIFYING MYSTERY FILES

Step 1: Google the file extension

Step 2: If step 1 fails, use DROID

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Digital Record Object Identification

http://www.nationalarchives.gov.uk/information-management/our-services/dc-file-profiling-tool.htm

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IDENTIFYING MYSTERY FILES

Step 1: Google the file extension

Step 2: If step 1 fails, use DROID

Step 3: If step 2 fails, open it in a hex editor

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HXD HEX EDITOR

http://download.cnet.com/HxD-Hex-Editor/3000-2352_4-10891068.html

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HEX EDITOR VIEW

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FILE SIGNATURES/MAGIC NUMBERS

• Every file type has a digital ‘finger print’ near the beginning of its code, sometimes called a ‘signature’ or ‘magic number’.

• In a hex editor, you can read the hexadecimal notation of the file and identify its magic number, then look up that number to identify the file type.

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WIKIPEDIA’S FILE SIGNATURE LIST

http://en.wikipedia.org/wiki/List_of_file_signatures

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IF YOU HAVE QUESTIONS ABOUT DIGITAL PRESERVATION

THE LIBRARY IS HERE TO HELP

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Shea SwaugerData Management Librarian

Morgan Library, 210Eshea.swauger@gmail.com

Questions?

This presentation is available at http://www.slideshare.net/SheaSwauger