Network publishing and mark-up languages

1
Network publishing and mark-up languages
2
p- versus e-form

• The share of documents in e-form and accessible
  over the network is growing fast.
• There are types of documents that will always
  exist in a paper form or co-exist in both forms.
• There are numerous types of documents that
  already function better in e-form, at least for
  some populations (or generations).
• The e-document can replace the paper form only if
  it is readable without limits of time and place.

3
Independence of place

• Document should be usable in the same way
  irrespective of servers distance and users
  hardware and software for reading.
• It is mainly a technological problem. We need
• a reader of a size and weight of a book,
• with screen with visual characteristics of a
  paper,
• with autonomous power supply,
• with wireless connection to servers with
  documents.
• All that we already have, but not in one
  reasonably expensive appliance.

4
Independence of time

• Document must have the same usability until
  potential readers disappear.
• It is mainly an organisational problem
• we need standard document formats, which will be
  understood by future generations of software and
  hardware, and
• we need consensus to obey those standards.
• Such standard formats are made by mark-up
  languages.

5
History of e-publishing

• At the beginning the creators of e-documents were
  few, mostly creators of bibliographic databases.
• They independently developed formats of their
  e-documents and software for their use.
• It was easy because e-documents were simple,
  ASCII files.
• Things became complicated with the development of
  more complicated, multimedia documents.

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History of e-publishing

• Because of the lack of standardisation new
  documents were not usable by definition on every
  operating system and brand of computer.
• Producers of e-documents were forced to develop
  different versions of documents and/or software
  for its use for all major brands of OS and
  computers.
• It was economically unfeasible and the only exit
  was standardisation.
• Standardisation of computers? Impossible.
  Standardisation of e-document formats.

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Mark-up languages introduction

• Mark-up languages must make possible
• the transfer of documents between different types
  of computers and software for reading,
• simple and economical transport through networks,
• longevity of documents (problem of e-archiving).
• Mark-up languages enable us to mark structure
  and/or form (appearance) of documents.

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Mark-up languages introduction

• Mark-up languages are artificial languages,
  composed of
• labels (tags) that divide document into
  structural elements,
• tags that describe appearance of structural
  elements, and
• syntax that defines appropriate use of tags.

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Structure vs. appearance

• If mark-up language defines only structure of a
  document, then its appearance on a screen or
  paper is entirely dependent on the software used
  for documents representation.
• In such case the structure of document is
  separated from definitions of fonts, colour of
  background, distance between lines, etc. With
  such attributes of documents the printing-house
  mark-up languages are dealing.

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RTF

• Very common type of e-documents are documents
  written with word processors, e.g. MS Word for
  Windows.
• Structure and appearance of documents are
  inseparable.
• The result is very limited possibility of
  transfer of documents between different types of
  computers or operating systems even between
  different generations of same word processor.
• More advanced is word processor, more closed
  system it is.

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RTF

• A strong need exist for transportability of word
  processor files.
• Developers of word processors agreed upon the
  common transport format, which is understood by
  the most programmes of that kind.
• This is RTF Rich Text Format.
• RTF denotes only documents appearance.

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RTF example
\rtf1\ansi\deff20\deflang1033\fonttbl\f4\froman
\fcharset0\fprq2 Times New Roman\f5\fswiss\fcha
rset0\fprq2 Arial\f20\fnil\fcharset0\fprq2
SLOHelvetica \colortbl\red0\green0\blue0\red
0\green0\blue255 ... 20 to 30 lines of lines
with general description of fonts and distances
follow ... \pard\plain \qr\sb40\sa40\tx357
\f20\fs20\lang2057 \fs18 Lecture Computer
communications, Databases 2 \par \pard\plain
\s18\sb40\sa40\tx357 b\f20\fs30\lang2057 \i\fs32
Predavanje Standardi za oznacevanje dokumentov
\par \pard\plain \s1\fi-360\li360\sb240\sa40\tx3
57 \b\f20\fs28\lang2057 1.\tab Reasons for
standardisation of document descriptio
tags for types and colours of fonts
tags for text positioning
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Postscript and PDF

• Postcript (Adobe)
• Mark-up language for driving laser printers.
• Marks only documents appearance, including
  images.
• PDF (Portable Document Format)
• Makes possible the original appearance of a
  document on a web browser.
• Documents on screen look the same as on the
  paper.
• Simplified and upgraded variant of Postscript.
• Marks appearance and only partly structure
  (hyper-text pointers).

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SGML

• SGML Standard Generalized Mark-up Language.
• International standard, adopted by ISO on 1986
  and upgraded several times since then.
• Family of standards, managing the mark-up of all
  known types of e-documents.
• Its strength is generality, because logical
  structure and appearance of a document are
  completely separated.
• Appearance is left to software for representation
  of documents on screen or paper.

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SGML

• SGML divides e-document into three parts
• Declaration, which describes the most general
  data about document (Latin or Cyrillic script)
  and symbols with special meaning for SGML.
• Document Type Definition (DTD), which describes
  the
• possible structural elements of document,
• their meaning,
• hierarchical relationship among structural
  elements, and
• tags that mark these structural elements.
• Body of a document, marked with tags.

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HTML

• SGML is not a real mark-up language but a recipe
  how to build mark-up languages for different
  types of documents.
• HTML is such language developed for web
  documents.
• It is relatively simple and this is the reason
  for extreme simplicity of web publishing.
• In its original versions it mostly defines
  structure and only partly appearance of
  documents.
• Author Tim Berners-Lee (early 90s).

17
HTML

• The standardisation of HTML is endangered since
  its birth.
• Big producers of web browsers, Microsoft and
  Netscape try to impose their own tags and
  functionality to beat the competition.
• Documents written with some word processors for
  HTML can not be read on browsers made by
  competition.
• It is safe to use simple Notepad or Netscapes
  editor.