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IWMW 2002: Web standards briefing (session C2)

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Web Standards Briefing session at IWMW 2002 event by Brian Kelly.

See http://www.ukoln.ac.uk/web-focus/events/workshops/webmaster-2002/materials/kelly1/

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IWMW 2002: Web standards briefing (session C2)

  1. 1. A centre of expertise in digital information management Web Standards Briefing Brian Kelly UKOLN University of Bath Bath, BA2 7AY Email B.Kelly@ukoln.ac.uk URL http://www.ukoln.ac.uk/ UKOLN is supported by:
  2. 2. A centre of expertise in digital information management 2 Contents • Introduction • Standards • The Original Web Architecture • Architectural Developments • Deployment Issues • Discussion Aims of Talk • To give brief overview of Web architecture • To describe developments to Web standards • To briefly address implementation models Aims of Talk • To give brief overview of Web architecture • To describe developments to Web standards • To briefly address implementation models Please feel free to ask questions at any time, especially to clarify any unexplained TLAs or XTLAs Please feel free to ask questions at any time, especially to clarify any unexplained TLAs or XTLAs
  3. 3. A centre of expertise in digital information management 3 About Me Brian Kelly: • UK Web Focus – a JISC-funded post to advise HE and FE communities on Web developments • Based in UKOLN - a national focus of expertise in digital information management based at the University of Bath • Involved in Web since 1993, while working in the Computing Service at University of Leeds • Represent JISC on the World Wide Web Consortium (W3C)
  4. 4. A centre of expertise in digital information management 4 Standards in HE/FE Context Standards are important in the HE and FE sector to: • Ensure widespread access to resources • Enables resources to be reused and repurposed • Ensure scholarly resources can be preserved • Address accountability of public funding • Minimise resource costs for upgrading systems • Provide universal access to resources (cf disability legislation)
  5. 5. A centre of expertise in digital information management 5 Standards Need for standards to provide: • Platform and application independence • Avoidance of patented technologies • Flexibility and architectural integrity • Long-term access to data Ideally look at standards first, then find applications which support the standards. However it can be difficult to achieve this ideal! Before the Web Access to resources typically required use of software vendor’s software – which was only available on limited no. of platforms. Often the software would be licensed. The goal of the Web was to provide universal access to resources. Who could argue with this goal? Before the Web Access to resources typically required use of software vendor’s software – which was only available on limited no. of platforms. Often the software would be licensed. The goal of the Web was to provide universal access to resources. Who could argue with this goal?
  6. 6. A centre of expertise in digital information management 6 Standards and the Web W3C • Produces W3C Recommendations on Web protocols • Managed approach to developments • Protocols initially developed by W3C members • Decisions made by W3C, informed by member & public review IETF • Produces Internet Drafts on Internet protocols • Bottom-up approach to developments • Protocols may be developed by interested individuals • "Rough consensus and working code" ISO • Produces ISO Standards • Can be slow moving and bureaucratic • Produce robust standards Proprietary • De facto standards • Often initially appealing (cf PowerPoint, PDF) • May emerge as standards PNG HTML Z39.50 Java PNG HTML Z39.50 Java HTML, XML, PNG, …HTML, XML, PNG, … HTTP URN whois++ HTTP URN whois++ HTML extensions PDF and Java? HTML extensions PDF and Java?
  7. 7. A centre of expertise in digital information management 7 The Case For W3C Standards Why use open standards developed by the W3C? Why not leave it to the marketplace?  W3C’s open standards have been developed in an open environment, with the aim of achieving platform and application independency  Commercial companies develop proprietary formats in order to maximise their profits and dividends to shareholders  W3C’s open standards have been developed to interoperate with each other according to W3C’s design vision  Commercial companies typically develop proprietary formats in isolation, or along the lines of a company vision
  8. 8. A centre of expertise in digital information management 8 Standards, Architectures, Applications, Resources This talk touches on several areas Architectures: models for implementing systems Architectures: models for implementing systems Standards: concerned with protocols and file formats Standards: concerned with protocols and file formats Open standards vs. Proprietary HTML / XML vs. PDF CSS / XSL vs. HTML GIF vs PNG Which standards are applicable NT / Unix File system / database application HTML tools / content management Apache / IIS FrontPage / Dreamweaver Oracle / SQLServer ColdFusion vs ASP Development vs. Migration costs Use of in-house expertise In-house vs. out-sourced Licensed vs. open source Resources: financial and staff costs needed to implement systems Resources: financial and staff costs needed to implement systems Applications: software products used to implement systems Applications: software products used to implement systems
  9. 9. A centre of expertise in digital information management 9 GIF As an example of the dangers of use of proprietary solutions, consider the GIF file format: • Unisys announce that they hold patent to compression algorithm used in GIF images and users of GIF will have to pay • Following much debate, Unisys require payment for licence from software developers - and also for end users of unlicensed software ($5,000!) • Web community responds with PNG format • See <http://burnallgifs.org/> WARNING: • There is no guarantee that payment will not be required for proprietary file formats which are currently free
  10. 10. A centre of expertise in digital information management 10 How Does The Web Work? The Web has three fundamental concepts: • URLs: addresses of resources • HTTP: dialogue between client and server • HTML: format of resources The Netsoft home page 1 User clicks on link to the address (URL) http://www.netsoft.com/hello.html 2 Browser converts link to HTTP command (METHOD): Connect to computer at www.netsoft.com GET /hello.html 3 Remote computer sends file Welcome to Netsoft 4 Local computer displays HTML file Web Browser Web server <HTML> <TITLE>Welcome</TITLE>.. <P>The <A HREF=“…”> Netsoft</A> home page</P>
  11. 11. A centre of expertise in digital information management 11 Approaches To HTML Emphasis on managing HTML resources inappropriate: • HTML is an output format, which cannot easily be reused (e.g. WAP, e-Books, etc.) • Need to manage HTML fragments (only partly achievable with SSIs) • Need to manage collections of resources • Need to have single master source of data • Need to support new developments such as personalisation • Difficult to integrate with new formats Issues • Should we stop giving HTML courses? • Should we stop buying HTML authoring tools? Issues • Should we stop giving HTML courses? • Should we stop buying HTML authoring tools?
  12. 12. A centre of expertise in digital information management 12 XML XML: • Extensible Markup Language • A lightweight SGML designed for network use • Addresses HTML's lack of evolvability • Arbitrary elements can be defined (<STUDENT- NUMBER>, <PART-NO>, etc) • Agreement achieved quickly - XML 1.0 became W3C Recommendation in Feb 1998 • Support from industry (SGML vendors, Microsoft, etc.) • Support in latest versions of Web browsers
  13. 13. A centre of expertise in digital information management 13 XML Concepts (1) Well-formed XML resources: Make end-tags explicit: <li>...</li> Make empty elements explicit: <img ... /> Quote attributes <img src="logo.gif" height="20" Use consistent upper/lower case <p> and <P> are different XML Namespaces: Mechanism for ensuring unique XML elements: <?xml:namespace ns="http://foo.org/ 1998-001" prefix="i"> <p>Insert <i:PART>M-471</i:PART></p>
  14. 14. A centre of expertise in digital information management 14 XML Concepts (2) XML Schemas • Allow constraints to be applied on XML attributes • Express shared vocabularies and allow machines to carry out rules made by people • Richer than DTDs • See <http://www.w3.org/XML/Schema> XSLT • A language for transforming XML from one DTD to another, or to another format (e.g. PDF) • Written in XML • Knows about XML (e.g. tree structures, etc.) • See <http://www.xslt.com/>
  15. 15. A centre of expertise in digital information management 15 XML Concepts (3) XLink provides sophisticated hyperlinking: • Links that allow you to choose multiple destinations • Bidirectional links • Links with special behaviours: • Expand-in-place / Replace / Create new window • Link on load / Link on user action • Link databases • See <http://www.xml.com/pub/a/2000/09/xlink/> XPointer • Provides access to arbitrary portions of XML resource • See <http://www.devshed.com/ Server_Side/XML/XPointer/page1.html> England France
  16. 16. A centre of expertise in digital information management 16 Getting to XML With XHTML XHTML: • HTML represented in XML • Some small changes to HTML:  Elements in lowercase <p> not <P>  Attributes must be quoted <img src="logo" height="50">  Elements must be closed: < p >... </ p >) <img src="logo" ... /> • Gain benefits from XML • Tools available (e.g. HTML-Kit from http://www.chami.com/html-kit/) • See <http://www.webreference.com/xml/ column6/>, <http://groups.yahoo.com/ group/XHTML-L/> and <http://www.ariadne.ac.uk/ issue27/web-focus/> Note the IWMW 2002 Web site is (mostly) XHTMLNote the IWMW 2002 Web site is (mostly) XHTML
  17. 17. A centre of expertise in digital information management 17 CSS CSS: • Cascading Style Sheets • XHTML/XML defines structure, CSS describes the appearance • CSS 1.0 and 2.0 now W3C recommendations • CSS 3.0 in preparation (modularised) • We should be using CSS:  Part of architecture  Ease of maintenance  Becoming much richer  Accessibility • See <http://www.w3c.org/Style/CSS/>
  18. 18. A centre of expertise in digital information management 18 SVG SVG: • Scalable Vector Graphics • A language for describing two-dimensional graphics in XML • See <http://www.w3.org/Graphics/SVG/ Overview.htm8> • Also see presentation on XML written in SVG at <http://www.w3c.org/Talks/2001/12/ IH-Euroweb/W3CInTheWorldslide.svgz> • WWW 2002 talk at <http://www.w3c.org/2002/Talks/ www2002-SVG/>
  19. 19. A centre of expertise in digital information management 19
  20. 20. A centre of expertise in digital information management 20 SVG Example http://www.karto.ethz.ch/neumann/cartography/vienna/http://www.karto.ethz.ch/neumann/cartography/vienna/
  21. 21. A centre of expertise in digital information management 21 SVG and XSLT This example: • Originally written in Java • Author realised that XSLT would be easier • Uses SVG for chess board and pieces • Uses XSLT to move pieces http://people.w3.org/maxf/ChessGML/http://people.w3.org/maxf/ChessGML/
  22. 22. A centre of expertise in digital information management 22 CML, SVG and XSLT http://www.adobe.com/svg/demos/cml2svg/html/index.htmlhttp://www.adobe.com/svg/demos/cml2svg/html/index.html A molecule described in CML can be transformed using XSLT into SVG, allowing it to be displayed and manipulated A molecule described in CML can be transformed using XSLT into SVG, allowing it to be displayed and manipulated
  23. 23. A centre of expertise in digital information management 23 SMIL SMIL: • Synchronized Multimedia Integration Language • A language for authoring of interactive audiovisual presentations • Allows you to synchronize text, images, audio and video in a document • An XML Application • See <http://www.w3c.org/AudioVideo/>
  24. 24. A centre of expertise in digital information management 24 SMIL Example http://www.kevlindev.com/tutorials/ basics/animation/svg_smil/index.htm http://www.kevlindev.com/tutorials/ basics/animation/svg_smil/index.htm http://www.reseau.it/smil/smilapp_en.htmlhttp://www.reseau.it/smil/smilapp_en.html
  25. 25. A centre of expertise in digital information management 25 MathML MathML: • An XML application for maths • Various plugins, dedicated readers, etc. • Mozilla renders natively See <http://www.mozilla.org/projects/mathml/>See <http://www.mozilla.org/projects/mathml/>
  26. 26. A centre of expertise in digital information management 26 Modularisation How can you: • Include XML resources such as MathML, ChemML, etc in XHTML documents? • Provide a subset of XHTML features in browsers on devices such as mobile phones, PDAs, etc.? The answer is: • XHTML modularisation (modularization ) • See <http://www.w3.org/TR/xhtml-modularization/> and <http://www.xml.com/pub/a/2002/01/16/ xhtml-m12n.html>
  27. 27. A centre of expertise in digital information management 27 Addressing (1) URLs have limitations: • Lack of long-term persistency Univ. changes name or department shut down or merged Directory structure reorganised • Inability to support multiple versions (mirroring) URIs: • Were an address of a resource – and moving a resource was annoying but not critical • With the development of “Web services”, structured resources, B2B communications, etc. the availability of URIs will be of great importance
  28. 28. A centre of expertise in digital information management 28 Addressing (2) Solutions: • Unique identifiers possible, but resolution difficult • Solutions include DOIs, PURLs, OpenURLs, etc. • Interest mostly in publishing sector • "URIs don’t break - people break them" • Think about URL persistency & naming guidelines: <http://www.ariadne.ac.uk/issue31/ web-focus/>
  29. 29. A centre of expertise in digital information management 29 Transport - The Original Roadmap HTTP/0.9 and HTTP/1.0:  Design flaws and implementation problems HTTP/1.1:  Addresses some of these problems  60% server support  Performance benefits! (60% packet traffic reduction)  Is acting as fire-fighter  Not sufficiently flexible or extensible HTTP/NG:  Radical redesign using object-oriented technologies  Undergoing trials  Gradual transition (using proxies)
  30. 30. A centre of expertise in digital information management 30 Transport - Today Today: • Responsibility for development moved from W3C to IETF • Little progress with HTTP/NG • Problems with HTTP/1.1: Lengthy (176-page) specification without much explicit rationale for design decisions Environment has become more complex Lack of a clean underlying data model … • See “Clarifying the Fundamentals of HTTP” <http://www2002.org/CDROM/refereed/444/>
  31. 31. A centre of expertise in digital information management 31 SOAP SOAP: • Simple Object Access Protocol • Facilitates development of machine-to-machine communications using Web protocols by providing a richer XML-based messaging mechanism • A protocol for invoking methods on servers, services, components and objects • Codifies existing practice of using XML and HTTP as a method invocation mechanism • See FAQ at <http://www.develop.com/soap/ soapfaq.htm>
  32. 32. A centre of expertise in digital information management 32 Metadata Metadata - the missing architectural component from the initial implementation of the web Metadata - RDF PICS, TCN, MCF, DSig, DC,... Addressing URL Data format HTML Transport HTTP Metadata Needs: • Resource discovery • Content filtering • Authentication • Improved navigation • Multiple format support • Rights management Metadata Needs: • Resource discovery • Content filtering • Authentication • Improved navigation • Multiple format support • Rights management
  33. 33. A centre of expertise in digital information management 33 Metadata Examples DSig (Digital Signatures initiative): • Key component for providing trust on the web • DSig 2.0 will be based on RDF and will support signed assertion: • This page is from the University of Bath • This page is a legally-binding list of courses provided by the University P3P (Platform for Privacy Preferences): • Developing methods for exchanging Privacy Practices of Web sites and user Note that discussions about additional rights management metadata are currently taking place
  34. 34. A centre of expertise in digital information management 34 RDF RDF (Resource Description Framework): • Highlight of WWW 7 conference • Provides a metadata framework ("machine understandable metadata for the web") • Based on ideas from content rating (PICS), resource discovery (Dublin Core) and site mapping (MCF) • Applications include:  cataloging resources  resource discovery  electronic commerce  intelligent agents  digital signatures  content rating  intellectual property rights  privacy • See <URL: http://www.w3.org/ Talks/1998/0417-WWW7-RDF>
  35. 35. A centre of expertise in digital information management 35 RDF Model RDF: • Based on a formal data model (direct label graphs) • Syntax for interchange of data • Schema model Resource ValuePropertyType Property page.html £0.05Cost 23-Mar-99 ValidUntil RDF Data Model page.html £0.05 23-Mar-99 Property Cost InstanceOf ValidUntil Value PropObj Cost PropName
  36. 36. A centre of expertise in digital information management 36 Browser Support for RDF Mozilla (Netscape's source code release) provides support for RDF. Mozilla supports site maps in RDF, as well as bookmarks and history lists See Netscape's or HotWired home page for a link to the RDF file. Trusted 3rd Party Metadata Embedded Metadata e.g. sitemaps Image from http://purl.oclc.org/net/eric/talks/www7/devday/Image from http://purl.oclc.org/net/eric/talks/www7/devday/
  37. 37. A centre of expertise in digital information management 37 RDF Conclusion • RDF is a general-purpose framework • RDF provides structured, machine- understandable metadata for the Web • Metadata vocabularies can be developed without central coordination • RDF Schemas describe the meaning of each property name • Signed RDF is the basis for trust But: • Is it too complex? • Is it the right approach? But: • Is it too complex? • Is it the right approach?
  38. 38. A centre of expertise in digital information management 38 RSS – An XML/RDF Application RSS (Rich / RDF Site Summary): • Initially XML, now an RDF application • Used for news feeds • Lightweight approach that we should be investigating (e.g. see news page on IWMW 2002 Web site) See example of an RSS authoring tool and parser at <http://rssxpress.ukoln.ac.uk/> See example of an RSS authoring tool and parser at <http://rssxpress.ukoln.ac.uk/>
  39. 39. A centre of expertise in digital information management 39 Model For News Feeds Good For User The end user can choose her news feeds, including local news, news from JISC services and news from third parties Good For Service The service can chose its own information flow model. Its news is disseminated automatically. Good For User The end user can choose her news feeds, including local news, news from JISC services and news from third parties Good For Service The service can chose its own information flow model. Its news is disseminated automatically. RSS Institution (e.g. Bath) RSSCommunity (e.g. MIDAS) RSS External (e.g. BBC) Local News .. JISC News .. National News XHTML converted to RSS Structured database converted to RSS Zope CMS outputs to RSS & XHTML
  40. 40. A centre of expertise in digital information management 40 What About Tomorrow? Two interesting areas: The Semantic Web • Will allow intelligent agents to know about resources • AI and ontologists meet the Web • Uses RDF (Resource Description Framework) – W3C’s framework for metadata • Some concerns over scale of problem • See <http://www.w3.org/2001/sw/> Web Services • Highlight of the WWW 10 and WWW 2002 conferences
  41. 41. A centre of expertise in digital information management 41 Web Services The Web: • Initially used for viewing static resources • Then interactive services built (e.g. e-learning) We now want: • Programmable Web services which can be used by other Web services using standards Web protocols We have experience of the first generation of externally-hosted Web services (stats services, voting systems, etc.) - see <http://www.ariadne.ac.uk/issue23/web-focus/>. The next generation will be programmable and machine- understandable Note that concerns over outsourcing may be an issue We have experience of the first generation of externally-hosted Web services (stats services, voting systems, etc.) - see <http://www.ariadne.ac.uk/issue23/web-focus/>. The next generation will be programmable and machine- understandable Note that concerns over outsourcing may be an issue
  42. 42. A centre of expertise in digital information management 42 Example Some examples at gotdotnet.com: • Mailsender • Thumbnail Generator Concepts been around for some time (see Auditing & Evaluating Web Sites workshop) Now being standardised (UDDI, WSDL, SOAP, …) http://www.gotdotnet.com/playground/ services/thumbnailgen.aspx http://www.gotdotnet.com/playground/ services/thumbnailgen.aspx
  43. 43. A centre of expertise in digital information management 43 We’ve Been Here Before Reusable components available on the network: • Sounds like COM/DCOM, CORBA, etc. for reusable program components Network services for use within a community: • Sounds like JISCmail, RDN, EDINA, MIMAS, BIDS, Mirror Service and other JISC Services • It’s outsourcing – but it’s OK! Web Services And UK HE / FE Communities Sounds like a great idea: • We’ve the organisational framework to develop national services (JISC, etc.) • We’ve got the network • We’ve a community which is willing to exploit centrally-provided services and wants to avoid reinventing the wheel (haven’t we?) Web Services And UK HE / FE Communities Sounds like a great idea: • We’ve the organisational framework to develop national services (JISC, etc.) • We’ve got the network • We’ve a community which is willing to exploit centrally-provided services and wants to avoid reinventing the wheel (haven’t we?)
  44. 44. A centre of expertise in digital information management 44 Currently... End user Local content National content International content Web Web Web Web Web Web We should be moving away from providing separate Web services with their own interfaces … We should be moving away from providing separate Web services with their own interfaces …
  45. 45. A centre of expertise in digital information management 45 Currently... End user Collection Description (e.g. Agora) User Profile (e.g. Headline) Authentication (Athens) Local content National content International content Web Web Web Web Web Web … and separate metadata repositories and access services (which are sometimes centralised) … … and separate metadata repositories and access services (which are sometimes centralised) … Agora and headline are eLib Hybrid libraries
  46. 46. A centre of expertise in digital information management 46 Future... Content End user User profile Collection description Authentication Metadata Services / Access (Web) Services Application Services? Bookmarks Spell- checker .. and move to Web-accessible, machine-understandable Web services as well as seamless access to content .. and move to Web-accessible, machine-understandable Web services as well as seamless access to content Brokered access provide by institutional portal (MLE, …)
  47. 47. A centre of expertise in digital information management 47 Other W3C Areas See • W3C site map at <http://www.w3c.org/Help/siteindex> • TimBL’s Web Design Issues at <http://www.w3c.org/DesignIssues> • Web Architecture from 50,000 feet at <http://www.w3.org/DesignIssues/Architecture.html>
  48. 48. A centre of expertise in digital information management 48 Architectures Let us consider the following areas: • Content Management • Systems Architecture • Access (Browser support)
  49. 49. A centre of expertise in digital information management 49 Position Today What should we be doing today? • Move away from creating new content in HTML • Move to XHTML as part of the migration • Deploying XML applications • Storing structured information in a neutral database • Using a CMS to manage our content • Deploying B2B applications to avoid human bottleneck (such as RSS) Note that these are aspirations. We will, of course, be constrained by existing systems, resource implications, vested interests, inertia, etc. Note that these are aspirations. We will, of course, be constrained by existing systems, resource implications, vested interests, inertia, etc.
  50. 50. A centre of expertise in digital information management 50 The CMS To The Rescue HTML authoring tools have limitations (as has HTML). A CMS (Content Management System): • Allows fragments to be managed • Allows collections to be managed • Allows resources to be stored in a neutral format (backend database) • Allows resources to be reused • Often provides access control • Often provides workflow processes and project management Issues • CMS can be expensive • CMS can be free but have support implications • Which one to choose? Issues • CMS can be expensive • CMS can be free but have support implications • Which one to choose?
  51. 51. A centre of expertise in digital information management 51 Content Management Storing resources in HTML and GIF/JPEG is:  Easy to do and is a low cost solution  Makes reuse and management of resources difficult GIF / JPEG XML TIFF / …. On-the-fly or batch conversion WML HTML User-agent Negotiation Content Management System for: • Management of content (content maintenance, metadata management, access rights, project management, …) • Delivery of content (e.g. user-agent negotiation, alternative file formats [such as WML], etc.))
  52. 52. A centre of expertise in digital information management 52 Systems Architecture Issues for you to consider: • Operating System: Should you go for a Unix OS or Windows NT? If Unix, should you go for Linux? • Open Source vs Licensed Solution: Should you go for an open source solution or buy a licensed application? • Package vs Do It Yourself: Should you make use of a pre-packages solution or develop your own solution based on a toolkit (e.g. database, scripting language, …)? There are no global solutions – your choice should be based on expertise available locally, resourcing issues, discussions with partners, solutions provider, etc. There are no global solutions – your choice should be based on expertise available locally, resourcing issues, discussions with partners, solutions provider, etc.
  53. 53. A centre of expertise in digital information management 53 Browser Issues Which approach to browser issues should you take? Web sites should be usable to old browsers as these are still in use and we aim to maximise access. Therefore you should deliver HTML 3.2 / 4.0 and avoid technologies such as JavaScript and CSS. Web sites should be usable to old browsers as these are still in use and we aim to maximise access. Therefore you should deliver HTML 3.2 / 4.0 and avoid technologies such as JavaScript and CSS. Old browsers are broken and fail to implement new technologies which provide (a) richer functionality (b) support for new devices and (c) better support for people with disabilities. Therefore you should use the latest stable versions of HTML (XHTML), CSS, etc. Old browsers are broken and fail to implement new technologies which provide (a) richer functionality (b) support for new devices and (c) better support for people with disabilities. Therefore you should use the latest stable versions of HTML (XHTML), CSS, etc. NOTE • Use of ‘clean’ HTML should degrade gracefully • XHTML is a useful transition • User-agent negotiation may be relevant QUESTION • Should organisations / community implement a browser policy?
  54. 54. A centre of expertise in digital information management 54 Conclusions To conclude: • Standards are important • HTML won’t do the job • XHTML is a useful transition • Many new standards being developed • Need to keep up-to-date and avoid developing systems with built-in obsolescence • We’ll need a CMS to manage richly functional institutional Web services • “Web services” should be important – and we shouldn’t be too concerned about using remote services
  55. 55. A centre of expertise in digital information management 55 Questions Any questions?

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