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<!DOCTYPE HTML PUBLIC "html.dtd"><HTML><HEAD><TITLE>Presenting XML:Potential Applications of XML:EarthWeb Inc.-</TITLE><META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW"><SCRIPT><!--function displayWindow(url, width, height) { var Win = window.open(url,"displayWindow",'width=' + width +',height=' + height + ',resizable=1,scrollbars=yes');}//--></SCRIPT></HEAD><BODY BGCOLOR="#FFFFFF" VLINK="#DD0000" TEXT="#000000" LINK="#DD0000" ALINK="#FF0000"><TD WIDTH="540" VALIGN="TOP"><!-- <CENTER><TABLE><TR><TD><FORM METHOD="GET" ACTION="http://search.itknowledge.com/excite/cgi-bin/AT-foldocsearch.cgi"><INPUT NAME="search" SIZE="20" VALUE=""><BR><CENTER><INPUT NAME="searchButton" TYPE="submit" VALUE="Glossary Search"></CENTER><INPUT NAME="source" TYPE="hidden" VALUE="local" CHECKED> <INPUT NAME="bltext" TYPE="hidden" VALUE="Back to Search"><INPUT NAME="sp" TYPE="hidden" VALUE="sp"></FORM></TD><TD><IMG SRC="http://www.itknowledge.com/images/dotclear.gif" WIDTH="15" HEIGHT="1"></TD><TD><FORM METHOD="POST" ACTION="http://search.itknowledge.com/excite/cgi-bin/AT-subscriptionsearch.cgi"><INPUT NAME="search" SIZE="20" VALUE=""><BR><CENTER><INPUT NAME="searchButton" TYPE="submit" VALUE=" Book Search "></CENTER><INPUT NAME="source" TYPE="hidden" VALUE="local" CHECKED> <INPUT NAME="backlink" TYPE="hidden" VALUE="http://search.itknowledge.com:80/excite/AT-subscriptionquery.html"><INPUT NAME="bltext" TYPE="hidden" VALUE="Back to Search"><INPUT NAME="sp" TYPE="hidden" VALUE="sp"></FORM></TD></TR></TABLE></CENTER> --><!-- ISBN=1575213346 //--><!-- TITLE=Presenting XML//--><!-- AUTHOR=Richard Light//--><!-- PUBLISHER=Macmillan Computer Publishing//--><!-- IMPRINT=Sams//--><!-- CHAPTER=18 //--><!-- PAGES=0331-0356 //--><!-- UNASSIGNED1 //--><!-- UNASSIGNED2 //--><P><CENTER><A HREF="0331-0334.html">Previous</A> | <A HREF="../ewtoc.html">Table of Contents</A> | <A HREF="0338-0340.html">Next</A></CENTER></P><A NAME="PAGENUM-335"><P>Page 335</P></A><P> overhead for systems such as these, not to mention the gargantuan effortof trying to maintain it.</P><P>It was, therefore, a fairly obvious step to start to move documentationaway from paper and distribute it electronically. Sun Microsystems was a pioneerin this area, at one point even offering customers a free CD-ROM player ifthey would agree to accept their documentation on a compact disc instead ofin paper form. Sun was prepared to offset the (then significant) cost of aCD-ROM drive against the major savings it would make in printing, storage,and shipping. With the move from the SunOS operating system towardSolaris, Sun has been moving almost completely away from paper documentation,so that the current recipient of a modern Sun workstation would actuallyreceive a fraction of the amount of paper that a PC (or even a Macintosh)purchaser would have to browse through.</P><P>Sun's online documentation application, called AnswerBook, has been agreat success. Based on PostScript versions of the printed documentation,the AnswerBook tool is easy to use and extremely useful. It provides the kindof hyperlinking that has since become familiar to anyone using a browser toview HTML pages on the World Wide Web (WWW), and it allows you tomake the same kind of bookmarks and annotations that are familiar to anyMicrosoft Windows Help users.</P><P>Not content with relying on past successes, in 1994 Sun (which is, afterall, the company that invented Java) started to appreciate that, despite themassive commitment that had been made in time and resources, AnswerBookwas beginning to reach the end of its usability and would not be able tocompete for very long with the developments that were happening on the Web.Sun therefore began to look seriously at alternatives to the currentimplementation of the AnswerBook software and to consider solutions for the future.</P><P>In the early 1990s, Sun experimented with HTML as an alternative, but itvery quickly became obvious that, while HTML was a very good format forpublishing and distribution, it was a very poor format for authoring, storage,and maintenance. The step "up" from HTML to SGML was a fairly naturalone, and one made by a lot of other companies both before and since. SGMLis, however, a time-consuming and initially very costly technology to adoptand, even for Sun, the argument for moving to SGML had to be convincingbefore it could be "sold to management."</P><A NAME="PAGENUM-336"><P>Page 336</P></A><P>The adoption of SGML and the move away from proprietary products toopen systems was a natural move—a move very typical of the state and spirit ofthe software industry of the late 90s. SGML was the perfect enablingtechnology to meet the majority of Sun's goals for its documentation—but not all ofthem. SGML provided the means for the documentation to be written andmanaged in a controlled and controllable environment. SGML's validationmechanisms (using a custom Solbook DTD) ensured that the input was directly able tobe stored and processed. However, looking to the future, Sun wanted to docertain things with its documentation that even pushed the limits of whatwas capable with SGML, such as link management.</P><P>The team tasked with finding and implementing a replacement forAnswerBook realized fairly early in their activities that an SGML solution was going tobe expensive. It was going to take a lot of time and effort and they weren'tgoing to be able to manage it on their own. The conclusion was that if theywere going to commit to this project, there was no point in settling for halfmeasures. The resulting goals were ambitious. The team that set out to rebuildSun's online documentation identified not just the creation of thedocumentation as its terrain, but also included its management and delivery as well in itsgoals, which are as follows:</P><UL><LI> To take the documents from the technical writers and package themin such a way as to make them available to all users (ideally with aslittle processing as possible).<LI> To support hyperlinking within and between separate "books"independently of where the books (that is, files) are physically located.<LI> To support context-driven searches.<LI> To support the manipulation by the users of the contents ofbook collections, enabling installation wherever they want.<LI> To enable the documents to be viewed outside the Solaris<LI>environment.<LI> To enable anyone to publish his or her own books within the<LI>environment.</UL><P>During the period that the development team must have been making itsinitial design decisions, the Internet exploded, HTML arrived, and theWWW became the phenomenon that it now is, with Java rapidly following. Itmust not have taken much to persuade the team to experiment with publishingits documentation in HTML. A lot of computer and softwaremanufacturers experimented</P><A NAME="PAGENUM-337"><P>Page 337</P></A><P> with HTML. However, HTML (as you have already seen)is simply not powerful enough, and many of the goals that the team had setsimply could not be realized with HTML. Java offered a way to compensate for someof the missing functionality, but very quickly the team was faced withadopting proprietary solutions once more. Worse, it was all very well to transformthe SGML it was using to author and process the documentation downwardinto HTML, but it seemed such a loss to discard all the structuralinformation in favor of something so very presentation-based as HTML. If nothing else,it was going to make the generation of dynamic tables of contents andindexes an extremely messy job. (How do you ensure that purelypresentation-oriented markup such as font changes and boldface do not get carried across?)</P><P>At this point, it is worth noting that the same Jon Bosak who is chairmanof the W3C SGML editorial review board (ERB) that approved the XMLstandard is employed by Sun Microsystems as an Online InformationTechnology Architect. With this in mind, it hardly seems a coincidence that theonline documentation team embraced XML from the beginning as the answer toall its goals. Using dynamic (Java-driven) SGML to XML conversion, Suncan now publish its documentation via the Internet—but it has gone muchfurther than this.</P><P>Via Sun's dedicated documentation Web server (currently at<A HREF="http://docs.sun.com/">http://docs.sun.com</A>, although it has not yet been widely publicized),the AnswerBook2 team is already publishing HTML and XML versions ofthe Solaris manuals converted dynamically from the SGML versions containedin the SolBook database. It is almost certain that when XML browsers makea serious entry into the marketplace, Sun will not hesitate to considermoving away from HTML.</P><P>Before leaving Sun's XML implementation of its online Solarisdocumentation, one experimental aspect of the software, though it is not directlyXML-oriented, deserves special mention because it gives an interesting hint ofsome of the things that can be achieved with XML in the future.</P><P>Given that XML is able to store its hyperlinks outside the documents thatare being linked, Sun has thought of an ingenious method of ensuring that abook will always be available. (Sun's goal is location-independent linking.) Usinga variation of the SGML Open Catalog (which is used to manage SGMLexternal <P><CENTER><A HREF="0331-0334.html">Previous</A> | <A HREF="../ewtoc.html">Table of Contents</A> | <A HREF="0338-0340.html">Next</A></CENTER></P></TD></TR></TABLE></BODY></HTML>⌨️ 快捷键说明
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