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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

3. Independence of place • Document should be usable in the same way irrespective of server’s distance and user’s 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

6. 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

7. 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

8. 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

9. 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 document’s 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

10. 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

11. 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 document’s appearance. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

12. RTF: example {\rtf1\ansi\deff20\deflang1033{\fonttbl{\f4\froman\fcharset0\fprq2 Times New Roman;}{\f5\fswiss\fcharset0\fprq2 Arial;}{\f20\fnil\fcharset0\fprq2 SLOHelvetica;}} {\colortbl;\red0\green0\blue0;\red0\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 označevanje dokumentov \par }\pard\plain \s1\fi-360\li360\sb240\sa40\tx357 \b\f20\fs28\lang2057 1.\tab Reasons for standardisation of document descriptio tags for types and colours of fonts tags for text positioning Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

13. Postscript and PDF Postcript (Adobe): • Mark-up language for driving laser printers. • Marks only document’s 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). Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

14. 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

15. 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. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

16. 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 90’s). Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.

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 Netscape’s editor. Alpe Adria Master Course :: Medical Informatics :: Dr. J. Dimec: Web publishing and mark-up languages.