| Instructors: Geoffrey Fox and Bryan Carpenter | |
| Dept. of Computer Science | |
| School of Computational Science and Information Technology | |
| 400 Dirac Science Library Florida State University Tallahassee |
|
| Florida 32306-4130 | |
| http://www.csit.fsu.edu | |
| fox@csit.fsu.edu 850-644-4587 | |
| dbc@csit.fsu.edu 850-644-0180 | |
Abstract of CSIT IT1 Fall 2000 Introduction
| This Foilset contains introductory material on CSIT/CS Course IT1 for fall 2000 | ||
| Some Aspects of Course Logistics -- all students must go to web site for complete discussion of this | ||
| http://aspen.csit.fsu.edu/it1fall00/ | ||
| Overview of Field and Material covered and relation to other courses IT2, IT3 (proposed) and the synergy between computational science and information technology | ||
| The Internet is the most important distributed computer system and it has spawned the most remarkable and general purpose software – In studying the Internet, we study distributed computing (hardware and software) | ||
| Students should be able to design and build any distributed system | ||
| Summary of Base Distributed Object Web and Internet Technologies | ||
| You are practically minded and wish to learn how to write real software to solve real distributed systems | ||
| Your software should work and be documented! | ||
| At the end of IT1 you will have basic knowledge for a .com job | ||
| At the end of IT2 and a good grade, you will be top applicant for .com job | ||
| At end of IT3, you will be prepared for PhD study in Information Technology | ||
| Grade will be based on about 6 homework sets. The first of these will be a report and the last a modest project. The rest will be largely Java oriented programming tasks | ||
| The Books are: | ||
| Core Java 2 | ||
| Volume 1-Fundamentals | ||
| Volume 2-Advanced Features | ||
| The Sun Microsystems Press Java Series (Prentice Hall) | ||
| Cay S. Horstmann and Gary Cornell | ||
| ISBN 0-13-081933-6 | ||
| ISBN 0-13-081934-4 | ||
Overview of CSIT Information Technology Courses - I
| IT1 assumes good programming skills and familiarity with the Internet/web | ||
| It will teach Java and use Internet examples to illustrate use of language | ||
| Course could be useful even if you know Java – we will emphasize topics like | ||
| Servlets – Simple way of building Java Server side applications | ||
| RMI – Foundation of pure Java distributed objects and systems built in these terms | ||
| JDBC (Java Database Connectivity) – Universal interface between Java and databases | ||
| The beat up client side (in Microsoft-Netscape battle won by MSFT) – Applets, Dynamic HTML and JavaScript (good ideas albeit a victims of battle) and Java Server Pages (how to build client software if you sell servers and don’t like MSFT) | ||
Overview of CSIT Information Technology Courses - II
| We will try to cover basic concepts of distributed systems and use the most elegant technology to illustrate – we will generalize to other approaches which could be best to use in a particular application | ||
| Servlets illustrate Server side application where you can of course use Perl, C++, JavaScript, Fortran, Machine Language or what have you | ||
| RMI illustrates the integration of Internet and distributed object ideas – the Object Web that underlies all modern distributed systems | ||
| IT1 will be basic 3 tier systems with core Client and Server Side technologies – Java, JavaScript and Dynamic HTML | ||
| IT2 will assume IT1 (including mastery of Java) and cover remaining core technologies | ||
| IT3 will cover the nifty new emerging ideas – if taught today it will cover the Wireless Internet and Computational Grids | ||
Overview of CSIT Information Technology Courses - III
| Provisional IT2 Syllabus | |||
| XML and some exemplar applications such as MathML | |||
| More on IT1 technologies such as Dynamic HTML with W3C (World Wide Web Consortium) Document Object Model | |||
| Virtual Machines and Java from pico to enterprise editions (Smart Cards to Cell Phones to PC’s to Servers) | |||
| Security for Java and for heterogeneous Systems (Public Key infrastructure, Kerberos) | |||
| The four approaches to the Object Web | |||
| CORBA from the Object Management Group | |||
| SOAP (Simple Object Access Protocol) from W3C – the pure web approach | |||
| RMI, Enterprise Javabeans (EJB) and Jini – the pure Java approach | |||
| COM from Microsoft | |||
| Component and event based programming – Javabeans on the client; CORBA and EJB on the server | |||
| Graphics on the Web: VRML X3D and SVG (Scalable Vector Graphics) | |||
Overview of CSIT Information Technology Courses - IV
| Some topics left over for “IT3” or other courses or Universities | ||
| Java API’s (frameworks) for Multimedia, Graphics | ||
| Java and High performance | ||
| Computational Grids - using internet for (parallel) Computing | ||
| The Wireless Internet – WAP, web clipping | ||
| Complete Web Frameworks like iPlanet (from Sun), ninja (from UC Berkeley) or e-Speak from Hewlett Packard | ||
| Applications: e-commerce, web-based education | ||
| Portals as the metaphor for web applications | ||
| Nifty companies and their technologies, Yahoo (Portals), Google (search), Real Networks (Multimedia), Ariba (Business to Business), Akamai (Caching and Routing), Inktomi (Web Infrastructure) | ||
| There are also other issues besides software | ||
| Algorithms for caching and multimedia | ||
| Communication hardware – conventional, optical, wireless | ||
| Communication architecture for Internet Services including quality of service | ||
| We will assume Basic Web Browsing and HTML expertise and programming experience | ||
| Permission of Instructor is needed for IT2 if you have not taken IT1 | ||
| You should be familiar with either PC or UNIX environment and program in at least one real language including Java | ||
| Perl is still widely used, but not taught here? | ||
| We will not assume any database or CORBA knowledge and will review basic material such as SQL if needed | ||
| CSIT provides servers for you to access Oracle databases and other needed core resources | ||
| You need a UNIX workstation or a PC running Windows | ||
| Computational Science is the Interdisciplinary field between computer science/engineering/math and application areas using simulation technologies | ||
| CSIT is the Interdisciplinary field between computer science/engineering/math and application areas using simulation and information technologies | ||
| CSIT can be studied from either a technology (CS CE Math) or an application perspective | ||
| It covers all of practical (applied) computer science and its application motivation | ||
| This course gives either technology or application scientists the base knowledge of information technology | ||
Computational Science and Information Technology (CSIT)
| Together cover practical use of leading edge computer science technologies to address “real” applications | |
| There are many technologies in common |
Is Computational Science an Academic Discipline?
| There can be no doubt that topics in Computational Science are useful and those in CSIT (Computational Science and Information Technology) are even more useful | ||
| CSIT incorporates trend towards data intensive computing and networked scientific collaboration | ||
| CSIT includes e-commerce | ||
| The CSIT technologies are also difficult and involve fundamental ideas | ||
| The area is of interest to both those in computer science and application fields | ||
| Probably most jobs going to Computer Science graduates really need CSIT education but unfortunately | ||
| Employers only know about “Computer Science/Engineering” | ||
| So most current implementations make Computational Science as a set of courses within existing disciplines | ||
| Situation could change though as CSIT is “correct” | ||
Components of a Basic Web System
Original Structure of World Wide Web
| Universal machine independent interfaces – Success of Web as much to with standards as software/hardware | |
| CGI Programs were originally usually written in PERL but can be essentially any Process and so do simulation, database access (this is JDBC), advanced document processing etc. | |
| Java (servlets) is of growing importance in Server Code |
The 1998 Information System Architecture
Distributed Object Web Technology Model - I
| Basic Vision: The current incoherent but highly creative Web will merge with distributed object technology in a multi-tier client-server-service architecture with Java based combined Web-ORB’s | ||
| Need to abstract entities (Web Pages, database entries, simulations) and services as objects with methods(interfaces) | ||
| CORBA .. XML is “just” CGI done right | ||
| COM(Microsoft) and CORBA(world) are competing cross platform and language object technologies | ||
| Every Netscape4 browser has a Visigenic ORB built in | ||
| Javabeans plus RMI and JINI is 100% pure Java distributed object technology | ||
| W3C says you should use XML which defines a better IDL and perhaps an object model -- certainly does for documents | ||
| How do we do this while technology is still changing rapidly! | ||
Multi-Tier Client Server Service
Distributed Object Web Technology Model - II
| Need to use mix of approaches -- choosing what is good and what will last | ||
| For example develop Web-based databases with Java objects using standard JDBC (Java Database Connectivity) interfaces | ||
| Oracle, DB2, Informix, Sybase, Lotus Notes, Object database choice becomes an issue of performance/robustness NOT functionality | ||
| Use CORBA (C++) or Java as software to wrap existing applications with XML as syntax to define these distributed objects | ||
| Note Middle tier insulates client from backend -- can use one object model for user level (object functionality) and different one for backend (object access and persistent store) | ||
| specialized object databases getting “overwhelmed” by multi-tier approach with Oracle etc. traditional backends | ||
| Program the server not the backend or the client | ||
| Do this programming in Java | ||
| And this implied that Oracle won the database battle as they got model correct and supplied an appropriate backend database with functionality added through middle tier extensions | ||
3-Tier Architecture and Different Object Models
| There are several important Object Models: COM, CORBA, Java, Web, Oracle Database …… | |
| But it doesn’t matter!! | |
| Examples of current object technologies | |||
| Documents -- URL | |||
| "General Programs including database invocations" | |||
| Old style Web -- CGI | |||
| New Style Web -- XML makes server side objects look like applets as far as invocation goes | |||
| CORBA and COM -- special "interface definition language" (IDL) defines invocation in C++ like syntax | |||
| RMI uses Java language as IDL language | |||
| Benefits of distributed objects | |||
| allows objects written in different languages to communicate seamlessly via standardized messaging protocols embodied by middleware. | |||
| Higher levels of transparency of interoperability | |||
| Objects can be “self-managing” of resources | |||
| provides flexible grain of decomposition for building complex systems | |||
Two More 3 Tier Web Database Links
Comparison of 2 3 and 4 Tier Models
Two ways of Implementing Data Objects
| Old way: Use an Object Database | |
| Current Approach: Use a Relational Database and business logic in EJB |
Today’s Distributed Object Web: The Confusing Multi-Technology Real World Middleware Server Layer
Emerging Object Web Multi-Server Model
Computational Science Portal: Multi-Server Web Computing System
Summary of Pragmatic Object Web
| 3-(or more)-tier architecture - Web browser front-ends, legacy (e.g. databases, HPC modules) backends; fat middleware | ||
| Use as appropriate the alternative / competing Middleware models: | ||
| Java RMI+ EJB (Enterprise Javabean) - single language solution by Sun | ||
| CORBA - all languages solution by OMG | ||
| COM - multi-language solution by Microsoft | ||
| SOAP/XML - emergent solution by the Web Consortium | ||
| Each model has different tradeoffs (most elegant, powerful, fastest, simplest) | ||
| POW attempts to integrate various models and services in terms of multi-protocol middleware servers | ||
| Note Java is often the best language to build middleware whether this is Java or some other distributed object model | ||
| Most commercial Java activity is on Server not Client | ||
| Originally we thought of Web Systems as a set of communicating objects with | ||
| Not much on client linking to UNIX processes invoked by CGI | ||
| Then we excitedly got balanced client server applications with JavaScript and Java applets on client which was faster as no network traffic for “small” local actions | ||
| Servlets, Enterprise Javabeans and CORBA provided robust middle tier programming model | ||
| But browsers never became a good programming environment as actions (say of JavaScript) undefined or quality (of Java virtual machine in browser) poor. | ||
| So browsers are just display technology and one should use servers or applications for software | ||
| Java Server Pages provide similar functionality to Java Applets with Java running outside browser in a nice robust server | ||
| This is the old way we built applications done with faster networks and more elegant implementation (we used to invoke Perl CGI scripts to provide dynamic web pages but this was too slow) | ||
Palm Tops help define Client Model
| There is growing interest in wireless portable displays in the confluence of cell phone and personal digital assistant markets | |
| One needs to design web systems so they can be accessed from either a PDA or a PC or a Powerwall | |
| This implies that only code in browser should be that immediately needed to relay events between user and web system – all “logic” (state) should be outside browser. |
Web Technologies in a Nutshell -- Java
| Java -- Objected Oriented version of C/C++ supporting Interactive Distributed Computing. | ||
| Original Web architecture (e.g. CGI) was server-side. Java allowed design and Implementation of balanced Client Server Applications but this original motivation is less important now | ||
| Java likely to be a dominant software engineering and Scientific Computing language -- see http://www.javagrande.org | ||
| This course discusses Java as a language in context of a system building tool | ||
| Java will probably be preferred language for development of next generation general or custom Web servers and clients | ||
| Programmers more productive in Java | ||
| Java has frameworks (libraries) for key Internet functionalities | ||
| Java can build client side customized GUI's and graphics/image processing but Microsoft JavaScript and DHTML competes here and MOST Industry use of Java is in middle tier | ||
| New Java 2 has several enhancements including very many specialized API’s | ||
| Javabeans are (visual) component model for Java applications | ||
| Enterprise Javabeans are Java middleware containers | ||
| Jini and RMI allow distributed objects to be found and communicate | ||
Web Technologies in a Nutshell - JavaScript
| JavaScript -- only superficially related to Java and was called LiveScript -- is Netscape's (somewhat supported by Microsoft) fully interpreted Client side extension of HTML. This is a good Client Window integration /customization technology where flexibility more important than performance | ||
| i.e. use JavaScript for Rapid Prototyping of Complex User Interfaces | ||
| First examples use JavaScript together with frames ( HTML extension) for interactive multi-window technologies | ||
| JavaScript is roughly equivalent to "Abstract Windowing Toolkit/ Layout Manager" in Java but applied to Browser Frames and not Java windows | ||
| JavaScript cannot build complex filters or simulations as slow | ||
| But JavaScript with dynamic HTML is powerful client technology which is often easier and faster than Java -- it is faster as invokes optimized browser functions | ||
| both Internet Explorer 4 and Netscape have excellent JavaScript support | ||
| Server side version of JavaScript called LiveWire runs on Netscape Servers -- unsuccessful | ||
| Originally expected client side use of JavaScript to grow in importance but new view of Web clients limits use of JavaScript to small critical event handling | ||
| JavaScript on Palmtops called WMLScript | ||
Web Technologies in a Nutshell - DHTML
| There is an emerging DOM or Document Object Model which will be uniform model used by W3C, Netscape, Microsoft | ||
| It allow you to address individual components of a page e.g. text box, image or collections thereof as separate entities | ||
| DOM is quite close to IE 5 conventions and is based on XML | ||
| DOM ought to be critical for publishing industry – Microsoft Word does not use except implicitly in Web export | ||
| Cascading Style Sheets allow one more powerful ways of assigning properties (such as color fonts etc.) to these components using either name(id) or type (<h2> tag etc.) | ||
| DHTML or dynamic HTML allows one to address the components of document and change on the fly (without reloading page) the properties of these components | ||
| This includes not only natural style properties but also position, size and “visibility” | ||
| DHTML currently handicapped by major differences between IE5 and Netscape 4 -- functionalities are similar but syntax very different | ||
| JavaScript combined with DHTML allows animations, graphs and replacement of just parts of text | ||
Web Technologies in a Nutshell - XML
| HTML is powerful but does not separate display and form (structure of document component as an object) | |
| XML is a generalization of HTML which allows definition of arbitrary tags | |
| e.g. <student name=“Jane Doe” class=“CSIT:IT1” grade=“…” >Working Hard</student> is more elegant way of capturing information in a reliable fashion than HTML | |
| <h2>Students</h2> <ul><li>Jane Doe: Working Hard</li><ul> <li>Class: IT1</li> <li>Grade: …</li> …. </ul> </ul> with a PERL program to extract data |
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| XML allows powerful way of defining dynamic ascii databases useful for “modest size data” such as people, document citations etc. | |
| XML parsers map XML tags into HTML for display or hand to programs to interpret | |
| XML can also be used to define extensions to HTML such as special tags for mathematics (MathML) or chemistry or ….. | |
| XML defines syntax for “serializing” Web objects and transmitting between clients and servers SOAP |
Web Technologies in a Nutshell - PERL
| PERL is a C like Interpreter with powerful direct access to UNIX system commands and very easy ways of processing text files | ||
| PERL is a relatively old technology which has being overtaken by Java tidal wave. | ||
| Still PERL has significantly better Systems and Document handling capability than Java | ||
| Very good for UNIX as much easier than Shell for system scripts -- PC versions exist but not so well integrated into O/S | ||
| Wonderful regular expression handling | ||
| PERL is traditional but not best choice for server CGI extensions and development of filters even for simpler cases involving text documents | ||
| PERL5 is object oriented but much less elegant (in my opinion) than Java | ||
| PERL5 has very useful multidimensional associative and regular arrays | ||
| Use PERL for UNIX batch jobs to edit text files (e.g. map www.npac.syr.edu to aspen.csit.fsu.edu) and quick simple Web server extensions – Convert latter to Java for production | ||
Web Technologies in a Nutshell - Databases
| The Web provides a convenient integration environment for "mature" technologies migrating from existing computer environments. | ||
| Object Relational databases are a good example where it is now straightforward in Microsoft Access, Oracle, DB2, Informix, Sybase etc. to provide a Web Interface to access and edit database with Java/JavaScript/Forms based Interfaces | ||
| Object databases such as Illustra also interfaced to Web but this is wrong way to thing about problem | ||
| Systems such as Cold Fusion and Dreamweaver provide convenient high level interfaces to Web-linked databases | ||
| Note Web Authoring “confusion” is another result of unfortunate browser war lost by Netscape | ||
| Several excellent Java to Database packages becoming available with the JDBC standard based on ODBC -- more powerful but lower level than systems like Cold Fusion | ||
| CORBA will have good Web and Java Interfaces and in IT2 we will discuss integration of Web CORBA and database technologies | ||
| CORBA views a database as a managed persistent object | ||
Web Technologies in a Nutshell - VRML
| VRML plays same role to 3D worlds that HTML does to documents | ||
| VRML 1.0 has been widely available and specifies static 3D scenes through which you can navigate. Already provides universal visualization environment and we have examples of use In Geographical Information Systems | ||
| Note can embed clickable URL's as with ImageMaps which can be used to annotate images to provide interactive resources | ||
| VRML 2.0 is now the standard with critical enhancements so that individual elements of 3D world are dynamic and can be programmed | ||
| It is designed to support full interactivity (televirtuality) with texture mapped video, avatars etc. | ||
| VRML 2.0 could require huge computing resources whether used as the virtual car-dealership / interactivity gaming or more academic uses such as collaboration between teachers and students in 3D virtual classroom | ||
| Bandwidth and computing needs of VRML are handicapping acceptance and appears that VRML will NOT “make it” -- replacement unclear | ||
| Microsoft ChromeEffects (XML based) and | ||
| Java3D address some but not all VRML applications | ||
| X3D is XML syntax for VRML | ||
| SVG is XML for Vector Graphics Primitives (much more limited but perhaps more realistic than VRML) | ||
Can Computer Science help Simulation Scientists ?
| There are classic computational science areas based high performance parallel computers and the software needed to use them | ||
| Cluster of PC’s to Teraflop machines in CSIT or DoD DoE NSF Centers | ||
| Nifty algorithms | ||
| New languages such as Java (Grande) optimized for performance | ||
| Information Technology can benefit simulations in many ways: | ||
| XML based scientific (meta)data standards to allow sensor data access to modern tools and support interoperability | ||
| Convenient access to multiple (super)computers and technology to integrate diverse simulations and data sources | ||
| Portal or “Problem Solving Environment” | ||
| Customization of generic portal services like real-time collaboration | ||
| We will look at this for a couple of examples | ||
Commodity Portals are Web Interfaces for Consumers
Portal for Landscape Management Simulation
Example of a custom
Web
User Interface
Land Management System
Interactive Mesh Generation Portal
| Security | ||
| Fault Tolerance | ||
| Object Lookup and Registration | ||
| Object Persistence and Database support (as in EIP’s) | ||
| Event and Transaction Services | ||
| Collaboration among scientists around world | ||
| Job Status as in HotPage (NPACI) and myGrid (NCSA) | ||
| File Services (as in NPACI Storage Resource Broker) | ||
| Support (XML based) computational science specific metadata like MathML, XSIL | ||
| Visualization | ||
| Programming | ||
| Application Integration (chaining services viewed as backend compute filters) | ||
| “Seamless Access” and integration of resources between different users/application domains | ||
| Parameter Specification Service (get data from Web form into Fortran program wrapped as backend object) | ||
Job Status in High End
Computing Portal
XML Separates Computer Data and Users