INFS 423 Preservation of Information Resources Lecture 13 Digital - - PowerPoint PPT Presentation

College of Education School of Continuing and Distance Education

2015/2016 – 2017/2018

INFS 423 Preservation of Information Resources

Lecture 13 – Digital Preservation

Lecturer: Prof. Harry Akussah & Mr. Michael Allotey, Contact Information: mallotey@ug.edu.gh, hakussah@ug.edu.gh

Lecture Overview

Digital preservation, even though mostly targeted at electronic documents is mainly focused on keeping the intellectual contents of electronic documents (digital information) and files available for time periods that can transcend technological advances. This Lecture introduces students to the preservation of the digital entities of electronic documents.

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Lecture Outline

The key topics to be covered in the lecture are as follows:

• Defining Digital Preservation
• Passive Preservation
• Active Preservation
• Basic Digital Preservation Practices
• Issues in Digital Preservation
• Physical Challenges in Digital Preservation.

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Reading List

• Akussah, H. (2011). Preservation of Documents. Department
• f Information Studies, Legon, NAB Superior Services.
• Gorman, G. E., & Shep, S. J. (2006). Preservation management

for libraries, archives and museums. London: Facet Pub.

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DEFINING DIGITAL PRESERVATION

Topic One

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Defining Digital Preservation

• Digital preservation is defined as the long

term storage of digital information with means for retrieval and interpretation for all the period that the information is needed.

• Digital preservation can be defined also as the

ability to keep digital documents and files available for time periods that can transcend technological advances without concern for alteration or less of readability.

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Types of Digital Preservation

There are two categories of approaches to the preservation

• f digital information resources:

these are:

• Passive Preservation
• Active Preservation

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PASSIVE PRESERVATION

Topic Two

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Passive Preservation

• This is a set of preservation processes which

ensure the continuous integrity and controlled access to digital documents whiles preserving their associated Metadata Characteristics as well. Essentially, passive preservation aims at keeping the original digital document intact without any interference in the technologies used to store process and access them.

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Passive Preservation

• There are two actions or procedures by

which passive preservation can be carried out. These are:

• Refreshing Data
• Replicating data

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Refreshing Data

• Refreshing is the process of copying data from one

medium to another of the same type. The process of refreshing does not result in the change of the bits and bytes of the data. The copy can easily be accessed using the same software without difficulty and is the original.

• Refreshing is necessary because storage media is

frequently unstable and can deteriorate. In addition, hardware needed to access and use data may also change, making it impossible for the storage media to be used. For example the change in 5¼ disks, to 3½ disks to CD drives

• n computers.

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Refreshing Data

• The periodic need to refresh electronic documents is

inevitable because of the continuous changes in electronic storage media. This can however be minimized by selecting the best and highest quality media of storage.

• Refreshed data must always be verified and validated

to ensure content consistency, corruption or loss.

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Replicating Data

• Replication a means of preserving digital information

is similar to the process of refreshing.

• The distinguishing difference is the fact that the

storage location of replicated document is not the same as the original document.

• Replication works on the principle that data existing

in only one location – the hardware and software could fail, someone could alter the content, delete the file or adulterate it; there could be fire, flood etc.

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Replicating Data

• Replication is also different from a backup since the

process may involve copying only specific electronic documents whereas a backup process copies usually the entire system including software.

• Accessing replicated documents requires knowledge
• f the software and hardware used to create it. This

makes it crucial for the preservation of the Metadata.

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Replicating Data

• Replication can be present a lot of difficulties to the
• rganization particularly if there are too many

replicated copies spread widely.

• They could pose difficulties of monitoring such

processes as version control, migration and access.

• The solution is to keep detailed information about

what has been replicated where stored and how

• ften they should be updated.

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ACTIVE PRESERVATION

Topic Three

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Active Preservation

• Active preservation is the preservation process that ensures

the continuous and long – term accessibility of electronic documents by actively intervening in how the documents are stored and managed.

• It involves moving the document into a new storage

environment which may depend on new technologies that were not in existence when the document was originally created and used.

• The process does not alter or corrupt the content of the
• document. It is only moving the document from one system

to another. Active preservation is often carried out by the process of Migration.

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Data Migration

• Migration is one of the most effective means of active

digital preservation. It is the process of transferring data from one computer format to another format in order to ensure that the document survives and users can access the document using new or changed computing technologies.

• It needs to be pointed out that during migration, the bits
• f data may change, thereby compromising integrity.

This calls for strict verification for authenticity and integrity during the process. One very basic example of a migration process is the “SAVE AS” option in Ms. Word.

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Types of Migration

• There are three categories or types of migration.

These are:

• Migration by Normalization
• Migration at obsolescence
• Migration on demand

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Migration by Normalization

• Normalization is the process of migrating digital

information from an original software into another open source, standard-based format so that it can be used without having to rely on the original software used to create it.

• Open source software refers to software for which the

source code is freely and always available to everybody.

• Normalization seeks to minimize the frequency and

complexity of future migration by converting documents straight to open source format.

• It must be noted that a normalized document is not an
• riginal document. Some information may be lost during

the process of migration.

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Migration at Obsolescence

• Migration at obsolescence may be seen as the
• pposite of normalization. It is at times referred to

as the “Just in time” migration.

• This approach advocates that electronic documents

should be migrated or transferred to other systems as and only when the technology they depend on is at the verge of becoming obsolete with apparent risk

• f the document becoming inaccessible.

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Migration on Demand

• This approach involves storing and maintaining

digital objects in their original format and only migrate them to current or new formats upon the request of a user or a prospective user.

• It is an adhoc approach which is not planned but

depends strictly on the “demand and supply”

• principle. It is only the particular document or

aspect of the document being requested that is

• migrated. The migration may be tied to the format

requested by the user as far as possible.

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Passive Vs. Active Preservation

• Passive and active digital preservation approaches

could be both used in one organization to solve the problems of access to electronic documents. It should however be noted that refreshing and replication (Passive preservation methods) are visually used as short term measures for preserving electronic documents during their active life in

• rganizations where as migration is the more

common approach to preserving documents for long – term purposes.

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BASIC DIGITAL PRESERVATION PRACTICES

Topic Four

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Basic Digital Preservation Practices

• Preservation of electronic documents should be seen

as an on-going process. There is no end to it unless the digital document ceases to be considered as worthy of preservation.

• For an effective preservation programme,

preservation actions must begin early in the life of the digital document, otherwise, it might not be possible to preserve the document or restore it in the near future.

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Basic Digital Preservation Practices

Protecting the authenticity of the electronic document involves performing several activities. Some of these activities are:

• Assessing Record-keeping Requirements
• Establishing Security and Access Control
• Ensuring the Integrity of Documents
• Managing Metadata
• Managing Storage Media
• Monitoring Technology Change
• Planning for Emergencies

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ISSUES IN DIGITAL PRESERVATION

Topic Five

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Issues in Digital Preservation

• Conceptual challenges
• Challenges to professional practice

–Preservation techniques –Content of digital resources –Physical custody –Quality of metadata

• Physical challenges

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Conceptual Challenges

• One of the most challenging issues in digital

preservation is the boundaries of digital resources. The traditional notions of preservation practice are based on the assumption of physical possession of the document by the preserving institution.

• This issue of physical possession is substantially

challenged in the digital world. Physical ownership

• f digital resources is no longer a constant for

heritage institutions.

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Conceptual Challenges

• One clear example is the fact that libraries subscribe or

are granted licenses for electronic journals. The subscription is for access and not ownership or

• possession. The ownership is retained by the publisher.
• This poses a problem for preservation. Who has the

ultimate responsibility of preservation when the library ceases its subscription or when the licenses for subscription expires. This is not the best because the publisher most often does not have the responsibility for long-term preservation and access that a library or archives may have.

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Challenges to Professional Practice

• Digital resources and their long – term preservation

create challenges for preservation professionals and heritage managers. The procedures and methods to deal with physical documents are well established. In the digital environment, things are different.

• Some of these challenges are discussed from slides

32 to 35.

Slide 31

Preservation Techniques

• Due to the frail nature of digital resources, the

continuous attention to hardware and software dependencies from the time of creation has moved the role of preservation from the tail end of the life of the document to become an integral part of collection management or records management from the point of creation or acquisition to the end of the life of the document.

• The requirement of digital preservation is no longer the

preserve of only the heritage institutions but now an on- going practice with creators and users of digital documents actively involved.

Slide 32

Content of Digital Resources

• In the digital world content is now being separated

from “Containers”. Re-use and repackaging of Information content is now paramount. The form of digital information is not static.

• Emphasis is now shifting to the context to enable

meaningful interpretation of content in both short and long term. There is the need for the preservation administrator to take on the additional responsibility of context documentation.

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Physical Custody

• Another changing role of the preservation administrator

is that he may not need to have physical custody of digital resources before making them available as in the tradition preservation practice.

• The world of networked computing over-rides the

requirement of housing resources in one single place.

• The implication however is that the preservation

administrator must have to negotiate access to digital resources in the long term regardless of where they are located.

Slide 34

Quality Metadata

• Quality Metadata is becoming very critical to most

preservation strategies. The old “Cataloguing” mindset relating to manual metadata must change in the digital world. Much of the Metadata is being created somewhere and is only inherited with the electronic resources by the preservation administrator.

• The administrator needs to be proactive to ensure

good quality metadata right from the point of creation or acquisition.

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PHYSICAL CHALLENGES IN DIGITAL PRESERVATION

Topic Six

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Physical Challenges in Digital Preservation

The physical nature and characteristics

• f digital resources introduces a

number of challenges in relation with their long-term preservation. These include:

• Technological Obsolescence
• Instability of storage media
• Risks to authenticity
• Loss of security and privacy

Slide 37

Technological Obsolescence

• Rapid Changes in hardware and Software technology

have led to what is referred to as technological

• bsolescence. Old systems become out of date and are

no longer supported by computer industry. This puts digital resources generated by the obsolete technology at

• risk. Long term access and use becomes difficult. This

has implications for preservation.

• Overcoming technological obsolescence often requires

frequent and considerable investment in financial, human and technological resources.

Slide 38

Instability of Storage Media

• Electronic storage media, whether optical or magnetic

are very unstable. It is difficult to establish the life span of most of the products and this poses a great challenge to digital preservators.

• In addition to the instability of these external storage

devices, the harsh environmental conditions under which computer storage media are sometimes stored contribute to their fast deterioration.

Slide 39

Risk to Authenticity

• As indicated earlier, changes in computer systems require

the migration of information to new technologies to ensure continuous accessibility. The process of migration can affect the authenticity and reliability of the information since the content or structure of the document may change in the process.

• Constant validation for content authenticity must be

carried out after every migration exercise.

Slide 40

Loss of Security and Privacy

Electronic or digital documents and records are maintained in large and complex databases. Access to them is often available electronically. Without proper security protections however, the information can be accessed by unauthorized people, threatening the privacy of the

• wners. In an electronic environment, right to privacy can

be violated either intentionally or by accident.

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References

• Akussah, H. (2011). Preservation of Documents.

Department of Information Studies, Legon, NAB Superior Services.

• Gorman, G. E., & Shep, S. J. (2006). Preservation

management for libraries, archives and museums. London: Facet Pub.

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