Current Preservation Strategies: needs and requirement

1.Introduction:				In copyright law, copying is known as "reproduction,"
In recent decades, many major libraries and archives				and it's one of the exclusive rights of the copyright
have established formal preservation programs for				owner. The right to publicly display a work is also an
traditional materials which include regular allocation of				exclusive right of the copyright owner, as is the right
resources for preservation, preventive measures to				to make an adaptation, known as a "derivative
arrest deterioration of materials, remedial measures				work." Our desire to keep digital information around
to restore the usability of selected materials, and the				for the future runs smack into the exclusive rights of
incorporation of preservation needs and requirements				the copyright owner.
into overall program planning. Preservationists within
the library and archival community have been
instrumental in developing an array of tools and				3.2.Storage Media.
methodologies to reduce the decay of traditional				The limited life of magnetic and optical media pose a
materials and to restore books and documents that				significant problem, although this is not the primary
have deteriorated to such an extent that their				limiting factor for digital preservation. Recent research
longevity and usability are threatened. Provisions for				on the longevity of magnetic media indicate a useful
fire protection and adequate environmental controls				life span of 10 to 30 years if they are handled and
frequently are incorporated into new library and				stored properly. Some optical disk technologies
archival facilities. The success stories and regular use				promise life spans of up to 100 years. Most
of established preservation methods are found				authorities argue that enhanced media longevity is of
almost exclusively in developed countries, and within				little value because current media outlast the
developed countries in preservation of print materials				software and devices needed to retrieve recorded
in major institutions (Preservation of Archival				information.
Materials).Digital preservation raises challenges of a				Nevertheless, improvements in the stability, capacity,
fundamentally different nature which are added to				and longevity of the base storage media are needed
the problems of preserving traditional format				to drastically reduce the vulnerability of digital
materials. By digital preservation, mean the planning,				materials to loss and alteration and to lower storage
resource allocation, and application of preservation				costs. Ample research and experience provide
methods and technologies necessary to ensure that				evidence of what can go wrong with magnetic media
digital information of continuing value remains				as a result of binder degradation, magnetic particle
accessible and usable				instabilities, and substrate deformation (Van Bogart).
2.Preservation Of material:				Optical media are susceptible to damage from high
				humidity, rapid and extreme temperature fluctuations,
Which strategies have the libraries, archives,				and contamination from airborne particulate matter
museums and their financial backers developed to				(U.S. National Archives and Records Administration).
protect their digital resources? One of the two				To prevent these problems, it is imperative to store
objectives of a digital resource preservation system				magnetic and optical media under strict environmental
is ensuring an intact and unadulterated digital data				controls that are not always available, affordable, or
stream: i.e. preserving the data content, which makes				convenient. Even modest improvements which
up the digital objects. This objective can be				produce storage media with larger per unit storage
successfully met if the objects stemming from				capacities and greater tolerance to variations in
heterogeneous sources and available on a wide range				temperature and humidity will lower preservation
of storage media can be separated as early as				costs by lessening the need for strict environmental
possible from their original carriers and transferred to				controls, reducing the frequency with which digital
a homogenous storage system. Those responsible				media must be "refreshed" through recopying, and
for archiving should preferably set up a functionally				decreasing the number of storage units that must be
autonomous system of several parts, the main task				handled.
of which is to preserve the digital resource materials.				This raises the question, however, of whether
A major part of this system is automated checking				research on incremental improvements in current
mechanisms, which monitor the continual internal				storage technologies will benefit preservation in the
transfer of data within the system. The short half-life				long run or whether we should seek alternative
of technical platforms necessitates a constant change				approaches to digital storage that more adequately
of data carrier generations and migration of data.				meet archival requirements. As a frame of reference
Permanent preservation of material is not possible if				it is worth remembering that microfilm, which is
the data material is inseparably linked to a particular				considered the only acceptable archival storage
data carrier and also to its fate. Technical measures				medium, lasts at least 300 years with minimal
designed to protect usage rights (e.g. copy protection				maintenance if stored properly. Last June, the Los
techniques) typically lead to conflict situations in the				Alamos National Laboratory announced the invention
medium term. In the meantime there is broad				of a High-Density Read-Only Memory (HD-ROM)
agreement that a digital archive can only take				technology that uses an ion beam to inscribe
responsibility for digital resources, the data material of				information on pins of stainless steel, iridium, or other
which they are capable of obtaining. Documentation				materials. The HD-ROM is capable of storing 180
of the "archiving status" is helpful in creating				times more information than current CD-ROM
transparency here.				technology at roughly one-half percent of CD-ROM
2.1. The challenges of digital preservation				costs. According to the release about this technology,
The purpose of preservation is to ensure protection				the HD-ROM is impervious to material degradation
of information of enduring value for access by				and it requires no bit stream interpreter because the
present and future generations. Libraries and archives				technology can describe in human-readable form all of
have served as the central institutional focus for				the instructions needed to interpret the data (LANL
preservation, and both types of institutions include				Ion Beam Storage). Such an approach illustrates the
preservation as one of their core functions. In recent				potential for solutions built on entirely new storage
decades, many major libraries and archives have				technologies.
established formal preservation programs for				4.Migration.
traditional materials which include regular allocation of				Better methods for migration of digital materials to
resources for preservation, preventive measures to				new generations of hardware and software are
arrest deterioration of materials, remedial measures				much needed for digital preservation regardless of
to restore the usability of selected materials, and the				breakthroughs in mass storage technologies. Planning
incorporation of preservation needs and requirements				for migration is difficult because there is limited
into overall program planning.				experience with the types of migrations needed to
Digital preservation raises challenges of a				maintain access to complex digital objects over
fundamentally different nature, which are added to				extended periods of time. When a custodian assumes
the problems of preserving traditional format				responsibility for preserving a digital object it may be
materials. By digital preservation, I mean the planning,				difficult to predict when migration will be necessary,
resource allocation, and application of preservation				how much reformatting will be needed, and how
methods and technologies necessary to ensure that				much migration will cost. There are no reliable or
digital information of continuing value remains				comprehensive data on costs associated with
accessible and usable. I intentionally use the term				migrations, either for specific technologies and
"continuing" rather than "permanent" value to avoid				formats or for particular collections, and little research
both the absolutism and the idealism that the term				underway on methodologies that would reduce the
"permanent" implies.				costs and burdens of migration.
2.2. Preserving usability				The preservation community as a whole would
"Preservation of material", however, is only one of				benefit tremendously from the development of
the prerequisites for ensuring the availability and				backward compatibility paths that would be included
usability of digital resources in the future. "Preserving				as a standard feature of all software. Backward
the usability" of digital resources is a significantly more				compatibility or migration paths would enable a new
complex task than preserving the data material. If				generation of software to "read" data from older
we take the scenario of a "depot system for digital				systems without substantial reformatting and without
objects" in which data streams are securely saved				loss of retrieval, display and computational capabilities.
and are stored in ways, which are impervious to				Although backward compatibility is increasingly
technical changes, we are still faced with a problem.				common within software product lines, migration
Without further support, we are incapable of				paths are not commonly provided between
interpreting the archived data stream as the				competing software products or for products that
technologies necessary for accessing it (operating				fail in the marketplace.
systems, user programs) are long since defunct. In				Stewards of digital material have a range of options
order to solve this problem, a number of different				for preserving digital information. One might preserve
strategies are being discussed and prototypes being				an exact replica of a digital record with complete
implemented and tested. Conserving system				display, retrieval, and computational functionality, or a
environments in hard and software museums and				representation of the record with only partial
keeping them available indefinitely is no longer				computation capabilities, or a surrogate for the record
regarded as a serious approach. The use of migration				such as an abstract, summary, or aggregation. Detail
techniques, by contrast, has already been proven for				or background noise might be dropped out
preserving digital data material for simpler data				intentionally through successive generations of
structures or across a generation change of data				migration, and custodians might change the format or
carrier types. Complex digital objects elude the				storage media. Enhancements are technologically
migration strategy, however, as the effort required				possible through clean-up, mark-up, and linkage, or by
for many individual cases is incalculable. For this				adding indexing and other features. These
reason, experiments are being carried out into				technological possibilities in turn impose serious new
techniques aimed at effectively emulating "historical"				responsibilities to present digital materials to users in a
system environments. In Germany a number of				way that allows them to determine the authenticity
different approaches are being pursued, amongst				of the information and its relationship to the original
which formalized descriptions of object structures				record. Methods to document changes in digital
and presentation environments play a prominent role.				objects during their life span need to be incorporated
All of these approaches apply late in the procedure				as an integral part of improved migration methods.
once the digital object, with its variable quality digital				There are few well-developed methods for
preservation characteristics, has already been				preserving and migrating software so that it might be
created. However, some key initiatives are aimed at				used to recreate digital documents that have the
promoting the use of long-term data formats and				"look and feel" of the original sources. Maintaining
open standards right from the stage at which the				repositories of obsolete hardware and software has
digital objects are generated. Regardless of which of				been discussed periodically, but usually dismissed out
these strategies is applied, preservation of usability				of hand as too expensive and not demonstrably
will not necessarily correspond to the original nature				feasible. This approach deserves more serious
of the original object. It will be necessary to				consideration as a strategy for maintaining continuing
concentrate efforts on the core functions of digital				access to certain types of digital materials. Feasibility
resources, i.e. primarily on the factor				studies and cost/benefit analyses should be
				conducted to determine the technological, economic,
2.3. Infrastructure of digital archives.				and commercial feasibility of maintaining selected
The ISO standard "Reference Model for an Open				legacy software systems and performing specialized
Archival Information System (OAIS)" -				migrations or, alternatively, of building and maintaining
describes the infrastructure of a digital archive in the				software emulators. Such an approach would support
form of a model. The model succeeds in establishing				replay of original sources and contribute to the
a generally applicable view of the core functions of a				preservation of software as a significant cultural and
digital archive which goes beyond the confines of				intellectual resource in its own right.
individual user communities, archives, data centers,
and libraries by delimiting and clearly labeling the				5. Management Tools.
function modules, interfaces and types of information				A fourth area for research is in the development of
objects. This represents a valuable basis for the				management tools for digital libraries and archives
relevant system operators to exploit synergies in				that integrate descriptive control and maintenance
commissioning, planning and implementing product				with storage technologies. Dynamic digital objects,
systems. The OAIS describes a number of different				such as those found in hypertext systems, pose
function modules, which reflect the data flow, and				special management problems for both current and
the work processes of the archive: ingestion,				future retrieval and reuse. The boundaries of
metadata management, archival storage, preservation				hypertext sources, like those found on the World
planning, administration and access. The "preservation				Wide Web today, are difficult to ascertain because
planning" function module consists in turn of four part				no single party or institution controls changes in the
systems which are responsible for monitoring the				nodes and links that make hypertext objects live and
environment conditions of the archive systems,				highly responsive information resources. A high
identifying the effects of technical changes as early				degree of volatility accompanies these objects
as possible and providing the basic planning for the				because the contents of nodes change, the sites
long-term preservation of the objects stored in the				where information resources are stored change, and
system. The "monitor designated community"				the links between nodes change, move, and vanish.
function ensures that current information on the				Some recent tools, such as the MOMspider (Multi-
users' needs is collated via interaction with the world				Owner Maintenance Spider) and Web: Lookout are
outside the archive system. The information permits				capable of traversing a portion of the Web and
ongoing adaptation of the archive system's access				noting maintenance problems such as broken links,
procedure in line with the changing habits of the user				moved documents, modified documents, and objects
world. This includes e.g. preferred data formats,				that have exceeded their expiration dates (Ackerman
access protocols and general communication via the				and Fielding). While tools such as these are useful for
system's external interface. The "monitor technology"				current maintenance, they do not address long-term
function facilitates monitoring of the development of				preservation concerns. If further developed to
digital technologies in the world outside the system.				address preservation problems, tools such as these
The aim is to identify, at an early stage,				have the potential to serve as filters, identify similar
developments which could have a harmful impact on				or identical objects, and monitor for maintenance
the usability of the objects stored in the system.				problems.
The "develop preservation strategies and standards"				Research and development of tools that would
function receives the information from the first two				imbed more intelligence about the preservation status
modules and converts it into action recommendations				of digital material into the objects themselves would
to the system administration. Such recommendations				make monitoring and maintenance of large digital
can relate e.g. to the application of new standards				collections more automatic. Current methods for
when accepting publications to the archive. The				monitoring the physical status of digital materials are
system administration stipulations are implemented by				labor intensive, unreliable, and potentially damaging to
the "develop packaging designs and migration plans"				the materials themselves. Recommended procedures
function. This includes implementing migration and				for monitoring physical deterioration of magnetic
emulation strategies. The information packages, which				tape, for example, involve reading a small sample of
are exchanged at the interfaces of the individual				tapes periodically to determine whether any data
modules of our archive system, receive instructions				losses have occurred (Eaton). The potential exists to
on their internal				build monitoring and reporting mechanisms into digital
3.Current Preservation Strategies and Their				objects, storage systems, and network architectures
Limitations.				that could support self- reporting of physical status
Most librarians and archivists have accepted the basic				and initiate automatic maintenance procedures.
wisdom -- for now at least -- that digital preservation				Despite differences, some lessons from traditional
depends upon copying, not on the survival of the				preservation are transferable to the digital
physical media. But copying, also referred to as				environment. In order to avoid commitments that far
"refreshing" or "migration" is more complex than				exceed available resources and costly rescue and
simply transferring a stream of bits from old to new				restoration efforts, preservation must become an
media or from one generation of systems to the				integral part of the planning, design, and resource
next. Complex and expensive transformations of				allocation for digital libraries and archives. Integration
digital objects often are necessary to preserve digital				of preservation requirements and methods with
materials so that they remain authentic				access and maintenance systems is essential to fully
representations of the original versions and useful				and efficiently support the processes of migration,
sources for analysis and research.				regeneration, and documentation of the life of digital
Probably the most commonly used preservation				objects. Planning for preservation must become an
strategy is to transfer digital information from less				integral part of the design and management of digital
stable magnetic and optical media by printing page				libraries and archives. If left as an afterthought, there
images on paper or microfilm. It seems ironic that				is little reason to believe that long-term preservation
just as libraries and archives are discovering digital				of digital information will be any more affordable than
conversion as a cost-effective preservation method				preservation of conventional formats has been.
for certain deteriorating materials, much information				6.Conclusion:
that begins its life in electronic form is printed on				Digital preservation raises challenges of a
paper or microfilm for safe, secure long-term storage.				fundamentally different nature, which are added to
Yet, high-quality acid neutral paper can last a century				the problems of preserving traditional format
or longer while archival quality microfilm is projected				materials. By digital preservation, I mean the planning,
to last 300 years or more. Paper and microfilm have				resource allocation, and application of preservation
the additional advantage of requiring no special				methods and technologies necessary to ensure that
hardware or software for retrieval or viewing.				digital information of continuing value remains
Perhaps this explains why in many digital conversion				accessible and usable. I intentionally use the term
projects, the digital images serve as a complement				"continuing" rather than "permanent" value to avoid
to rather than a replacement for the original hard				both the absolutism and the idealism that the term
copy materials (Conway, 1994).				"permanent" implies.
Another strategy for digital preservation is to				7.References.
preserve digital information in the simplest possible				Ackerman, Mark S. and Roy T. Fielding. (1995).
digital formats in order to minimize the requirements				"Collection Maintenance in the Digital Library," URL: .
for sophisticated retrieval software. As new media				Bearman, David and Ken Sochats, (1995). "Metadata
and storage formats were introduced, the data were				Requirements for Evidence," Draft, maintained on the
migrated without any significant change in their logical				WWW server for the University of Pittsburgh
structure. This approach has the distinct advantage				Project, Functional Requirements for Recordkeeping,
of being universal and easy to implement. It is a				URL: .
cost-effective strategy for preserving digital				Conway, Paul. (1994). "Digitizing Preservation." Library
information in those cases where retaining the				Journal, (February 1, 1994): 42-45.
content is paramount, but display, indexing, and				Conway, Paul. (1990). "Archival Preservation in a
computational characteristics are not critical. As long				Nationwide Context," American Archivist, 53, No. 2:
as the preservation community lacks more robust				204-22.
and cost-effective migration strategies, printing to				Eaton, Fynnette L. (1993). "The National Archives and
paper or film and preserving flat files will remain the				Electronic Records For Preservation," in Preservation
methods of last resort for many institutions and for				of Electronic Formats: Electronic Formats for
certain formats of digital information.				Preservation, Janice Mohlhenrich, ed., Ft. Atkinson, WI:
This approach has the advantage of preserving more				Highsmith Press: 41-61.
of the display, dissemination, and computational				Giguere, Mark D. (in progress). "Electronic Document
characteristics of the original materials, while reducing				Description Standards: A Technical Feasibility of Their
the large variety of customized transformations that				Use in the Augmentation of the Microform
would otherwise be necessary to migrate material to				Preservation of Contextual Cues Embedded in
future generations of technology. Although this				Structured Electronic Documents During Successive
strategy simplifies migration and may lower digital				Digital/Analog/Digital Reformatting," dissertation
preservation costs by reducing the amount of				proposal submitted to the School of Information
customized reformatting needed as technology				Science and Policy Studies, State University of New
changes, it does not eliminate the need for regular				York at Albany, (January 5, 1995).
migration of digital materials. Software and standards				Gould, Constance. (1988). Information Needs in the
both continue to evolve and even repositories with				Humanities: An Assessment, Stanford, CA: The
structurally homogeneous holdings can expect to be				Research Libraries Group.
required to migrate their digital materials periodically.				Graham, Peter S. (1995). "Requirements for the Digital
Migration strategies that involve reformatting of				Research Library," College and University Research
digital materials to a simple standard format usually				Libraries, July 56, No. 4: 331-39.
eliminate the structure of documents and relationships				"LANL Ion Beam Storage Holds 180 Times More Info
imbedded in databases. Computation capabilities,				than CD-ROMS," Science and Engineering News, June
graphic display, indexing, and other features often are				23, 1995, down loaded from HPCwire and
lost, thus limiting future analytical potential.				redistributed to .
Normalization to standard formats is not always				Lesk, Michael. (1992). Preservation of New
technically feasible and it usually is quite costly.				Technology: A Report of the Technology
Archives and libraries must also contend with entirely				Assessment Advisory Committee to the Commission
new forms of electronically enabled discourse and				on Preservation and Access. Washington, D.C.,
new forms of artistic and cultural expression that do				Commission on Preservation and Access.
not have predecessors in the analog world. No				Levy, David M. and Catherine C. Marshall. (1995).
current preservation method is adequate for				"Going Digital: A Look at Assumptions Underlying
preserving dynamic data objects from complex				Digital Libraries," Communications of the ACM, 58, No.
systems. There are no established conceptual models				4: 77-84.
or technical processes for preserving multi-media				Lynch, Clifford. (1994). "The Integrity of Digital
works, interactive hyper-media, on-line dialogues, or				Information: Mechanics and Definitional Issues," Journal
many of the new electronic forms being created				of the American Society for Information Science, 45,
today. The archival requirements to preserve				No. 10: 737-44.
content, context, and structure and to maintain the				Michelson, Avra and Jeff Rothenberg. (1992).
capability to display, link, and manipulate digital objects				"Scholarly Communications and Information
only heighten their software dependency.				Technology: Exploring the Impact of Changes in the
3.1Digital Preservation and Copyright.				Research Process on Archives," American Archivist
If all information in the world was written on clay				55, No. 2: 236-315.
tablets or carved into marble, its preservation would				O'Toole, James M. (1989). "On the Idea of
be greatly simplified. Even paper, when manufactured				Permanence," American Archivist, 52, No. 1: 10-25.
and stored properly, can have a life measured in				The Preservation of Archival Materials. (1993).
hundreds of years. Today, however, much of the				Washington, D.C.: Commission on Preservation and
information being produced is digital and digital				Access.
formats are notoriously fragile. Either the media on				Preserving The Intellectual Heritage: A Report of The
which the information is stored becomes unreadable,				Bellagio Conference. (1993). Washington, D.C.: The
or the hardware and software needed to read the				Commission on Preservation and Access.
work becomes obsolete. Think of that old 8" floppy				Rothenberg, Jeff. (1995). "Ensuring the Longevity of
disk in the back of the drawer with your attempt				Digital Documents," Scientific American, 272 No. 1:
from twenty years ago to write the Great American				24-29.
Novel (in WordStar). The magnetic data might not still				Task Force on Archiving of Digital Information. (1995).
be readable; drives that can read the disk are scarce;				"Preserving Digital Information," Report of the Task
and few word processing packages today can				Force, commissioned by the Commission on
understand WordStar documents.				Preservation and Access and The Research Libraries
To preserve analog information resources, it is often				Group, Version 1.0, August 24, 1995.
sufficient to house them in a benign environment. In				U.S. National Archives and Records Administration.
particularly bad cases, it might be necessary to make				(1994). Digital Imaging and Optical Digital Disk Storage
a microfilm or xerographic copy of the original, but				Systems: Long-Term Access Strategies for Federal
copying is the exception rather than the rule. Digital				Agencies. Technical Information Paper No. 12. National
preservation, however, starts with copying. At a				Technical Information Service, Washington, D.C. URLs:
minimum, files need to be copied from obsolete or				and .
decaying media, such as 8" floppy disks or 5 "				University of the State of New York, State
floppies, to current storage media. Good preservation				Education Department, State Archives and Records
practice requires much more, including making multiple				Administration. (1995). Building Partnerships for
copies of files. Digital documents may need to be				Electronic Record keeping: The Final Report and
changed from WordStar to WordPerfect to Word				Working Papers of the Building Partnerships Project.
format, or perhaps even converted to PDF or XML				Albany, NY.
format. Every time you use a digital file, you must				Van Bogart, John W. C. (1995). Magnetic Tape
copy it. When digital documents are displayed in a				Storage and Handling: A Guide for Libraries and
computer, they are copied from the storage medium				Archives, Washington, D.C.: Commission on
into the RAM memory of the computer where it is				Preservation and Access and the National Media
then displayed. Digital preservation and access is all				Laboratory.
about copying.

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Current Preservation Strategies: needs and requirement

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