Digital Documents and Libraries Adolf Knoll National Library of the Czech Republic © Adolf Knoll, National Library of the Czech Republic

Communication Creator of information Receiver of information Information delivery Receiver of information Receiver of information Receiver of information Receiver of information Multiplying information

What is transmitted? Information that can be perceived by human senses:  smell (we can receive the smell of the cooked meals)  taste (we can taste the wine)  touch (we can touch various objects to discover their properties)  hearing (we can hear information, e.g. music)  sight (we can see objects)

What is emitting information? Physical Object Artefact It smells well It cools when touched It can be seen It tastes well It can be heard when opened and even poured in glasses However, what remains from this information if the artefact and the action are encoded in a document ?

What is a document? A surrogate of the reality, its reflection fixed (written) on a physical carrier.

How this surrogate works?

… and if it is sound, how does it work for me? It makes me remember specific moments of my personal life

… variety of remembrance For you? For me? No context Rich context

What a document can transmit? The document bridges two worlds: that of the its creator and that of the receiver of the information message. Each receiver processes the same information message differently: during its interpretation, he uses his knowledge, his experience, his own feelings. Thus, the results differ from one another.

Basic message Basic message Basic message Basic message Original DocumentRecreated original Added information Added information

Created work Created Work Multiplied distribution copies Understood Work

Multiplying information Growing possibilities manual copying (from inscriptions in stone to manuscripts produced in scriptoria) printing (the number of copies grows) analogue copying (Xerox, audio recordings, motion pictures,...) digital copying and delivery

Problems Fidelity of copied information Durability of information carrier Decoding process These factors have a strong influence on our understanding of what the creator wanted to share with us. End

Fidelity The digital copying can solve the fidelity, because we are able to copy all the bits. However, digitization is not copying, it is re-encoding of information into another system. Digitization is conversion of the analogue scheme into the digital scheme. Any change of parameters of the digital format or any conversion from one digital format into another can affect the fidelity.

Change of parameters Digital audio recording - reducing the bit rate: MP3 128 Kbit/s MP3 34 Kbit/s Digital image - reducing the number of colours: 256 colours 16 colours 2 colours

256 colours/8 bit 16 colours/4 bit 2 colours/1 bit

Converting between digital formats Through this conversion losses of information can take place. In order to avoid this situation, we must know the characteristics of the most used digital formats. E.g.: converting from JPEG into GIF, we reduce the number of colours.

Durability of information carriers In the analogue world, this is the most critical problem. In the digital world, it is a problem of good organization of digital archiving system. The problem can be high amount of carriers to be monitored - certain reliability of CDs (the redundancy of written-on information can be measured; the copying should be made before reaching the critical point)

Decoding process The decoding process is the most critical point in both analogue and digital worlds. The only difference is that the development of digital schemes and platforms is faster. This is an Egyptian papyrus; we can still read it and understand it.

Latin Iste liber pertinet ad dominam abbatissam de convento Georgio Chunegundem filiam Othakari Regis Bohemie.

Etruscan The carrier is well preserved. The letters are evident. Nobody understands the message.

Digital resources Digital Library On-line external documents In-house digitization products Physical media documents

Physical media documents Issued by various publishers CD, DVD, diskette Great variety of application/access software versus uniformity of audio CD National Libraries face their long-term preservation The documents include also software releases and games

Physical media documents Critical factors Information carrier: unreliable diskette and relatively reliable CD (possibility to measure the data redundancy) Access software: very critical Data and metadata formats: very critical SW/HW platform dependence We must try to keep them unbound as much as possible from one another.

Access software HWSW Metadata Data

On-line external documents We do not acquire them physically, we do access them on networks Should we try to preserve them as NL? What is their storage format? What we see, it is frequently a transient document formatted for us (often into HTML) or a part of a static source only.

On-line external documents Data Source request delivery Partial or Transient Document

In-house digitization and publications Great chance to behave cleverly To consider all the possible long-term access problems before to start This can cost more now, but it will surely save much more money in future The most general recommendation: STICK TO THE MOST WIDESPREAD STANDARDS for developing your applications.

In-house digitization and publications Once started, we are responsible for availability of our products. Production Research Development Research Development Trying to describe the relevant aspects of these activities.