LSL Communications with Internet

LSL has a syntax and operator set that will be familiar to C or Java programmers, but is not object oriented. Mainly it has a large number of built-in functions and event handlers specific to the 3D virtual environment and the manipulation of user-created objects. In addition to the string and numeric variable types, there are variable types specific to location and movement in the 3D world which provide the basis for dramatic animation effects. Collections are limited to a list type which can hold any of the other variable types.

LSL Connection Options

At present, the LSL scripting language provides three interfaces for communication with the Internet, e-mail, XML-RPC and HTTP requests.

• E-mail can be sent both inside Second Life and to Internet addresses. To reduce load on the servers and prevent use for spam, there are limitations on how frequently an object can send e-mail and enforced delays for each piece of mail sent.
• XML-RPC (Remote Procedure Call) is a specification that allows software running on disparate operating systems to make procedure calls over the Internet. It uses HTTP as the transport and XML as the encoding. The current implementation of XML-RPC in Second Life only allows ONE request to be queued on the front-end server at a time. Any additional requests to the same data channel overwrite any pending one. This has serious ramifications for the design of XML-RPC communications where the in-world object could receive requests faster than it can respond to them. In addition, the 3-second delay in llRemoteDataReply exacerbates this problem even more.
• The http request facility appears to be the most flexible since, in contrast to xml-rpc, each server handles requests directly. When a script calls to llHTTPRequest function, the language automatically associates a matching http_response event handling method which will get the resulting response. Requests can use GET, POST, PUT and DELETE methods. However, at the present time there is a limit of 2048 characters in a request or response body, so a verbose format like XML is probably not a good idea. Also the language does not presently support any XML manipulation tools like XPath.

In summary, the connection options offered by LSL to communicate with outside world are quite limited in terms of functionalities. For the http request mode, clever programming will be required to get the most out of the limited message size.

For the case that the XML-RPC is used for the communications, the observed issue might be this: if you send multiple quick requests to an in-world object via XML-RPC, one which is scripted to perform some processing and then return a response (via llRemoteDataReply), there is a potential for earlier requests to get lost on the front end server (they still should generate remote_data events, though), and have the response meant for an earlier request end up being passed back to a later one, while the earlier requests will time out back at your external application.

As a result, if you intend to do any serious work with XML-RPC, you will have to design your external client application to manually serialize all requests to each individual RPC channel. That means you have to wait for a response from the previous request before you attempt to send the next one. If you don’t care about receiving responses, then this problem is not an issue, as all requests seem to get passed on to the script, regardless of the queueing issue.

Also note that there is NO way to get around the 3-second delay for llRemoteDataReply; you cannot use the multiple-slave-comm-script trick, because XML-RPC channels are *script-specific*, NOT *object-specific*.

Example Usage of Second Life for Libraries, galleries and museums

Some interesting slurl are given below:

Example Usage of Second Life for Distance and Flexible Education

Second Life provides an excellent platform for flexible delivery and online education. Students and facilitators can come together in the Virtual World to share information and resources via slides, audio and video, engaging in discussions, presentations, group projects and explorations.

Cyber One: Law in the Court of Public Opinion

Harvard’s Berkman Center for Internet and Society has a course on the creation and delivery of persuasive argument in the new integrated media space constituted by the Internet and other new technologies. The course uses Web 2.0 tools such as WiKis and blogs and extension students meet in Second Life on Berkman Island (SLurl).

You can watch the course introduction on the YouTube video – Harvard Extension School in Second Life, or a tour of the Harvard Extension School in Second Life on blip.tv or get more information on the website – CyberOne: Law in the Court of Public Opinion.

Second Life Writing: ENG104 at Ball State University

Sarah Robbins of Ball State University used Second Life to teach an English class focussed on writing for academic research in 2006. The course was a hybrid course with at least half of the class time spent online, based at Middletown (SLurl), which is sponsored by Ball State’s Center for Media Design Educational Environments. Visitors were welcome to observe the class.

English 104 applied the fundamentals of rhetoric to the research process, introducing students to methods of research. The many communities of Second Life provided students with rich opportunites for observation, research and interaction with other cultures, as well as many interview subjects for use in their writing.

Read more in the article Ball State students immersed in virtual world to study cultures or on the class website ENG104 in Second Life.

Educational Usage of Second Life

Second Life provides a unique and flexible environment for educators interested in distance learning, computer-supported cooperative work, simulation, new media studies, and corporate training.

Second Life provides an opportunity to use simulation in a safe environment to enhance experiential learning, allowing individuals to practice skills, try new ideas, and learn from their mistakes. The ability to prepare for similar real-world experiences by using Second Life as a simulation has unlimited potential!

Students and educators can work together in Second Life from anywhere in the world as part of a globally networked virtual classroom environment. Using Second Life as a supplement to traditional classroom environments also provides new opportunities for enriching existing curricula.

A good starting point to read about educational projects in SL is the Education section of their website. The picture below shows a university campus in SL.

Another good example of educational activities in VR is the Second Life Future Salon, which meets once a month in the Metaverse to discuss innovation in digital worlds and culture, information technology, simulation, video games, massively multiplayer online role-playing games, 3D creation tools, computer-aided design (CAD) and 3D prototyping, the geospatial Web, augmented reality, and all forms of digital environments plus the technology, social, and business dialogues that can be impacted by them.

Many universities and educational institutions are already using Second Life, and you can find an updated list of them here.

The Second Life website maintains a Second Life Educators mailing list (SLED) to keep interested individuals alerted to education opportunities and events in Second Life. This list is also an opportunity for educators to communicate with each other as well as find new colleagues. If you want to quickly get up to speed and learn from the shared experiences of other educators in Second Life, or if you have questions about how to best use Second Life with your education projects, that is the best place to start!

The Second Life website also maintains other education-related mailing lists to help you find colleagues and share ideas on more specific topics. In addition to joining the comprehensive SLED list, you might like to join these more focused discussions. They are Educators Working with Teens, Healthcare Support and Education and Non-profits.

Second Life also has a number of active groups who collaborate inside the Virtual World and who keep intouch using the group system tools of the Second Life application. To join a group click the “Find” button and search under Groups for “Education”.

Linden Lab, the creator and operating company of Second Life, has a special offer for educators interested in trying out Second Life for the first time. It’s a temporary land grant for the duration of a semester, and is called Campus: Second Life.

If you would like a place of permanence in Second Life, Private Island ownership lets you create a secure “intranet” space with restricted membership for your students and faculty, or you can open it up to be accessible to everyone in Second Life. Linden Lab offer a discount for Private Islands to educational institutions and non-profit organizations, and you can find details on the Private Island order page.

Get started with Second Life

To get access into the virtual world “Second Life” and have a taste of it, you must first sign up for Second Life. Although setting up for Second Life is pretty easy and straightforward, there are some key stpes you’ll need to take.

1. Check that whether you computer meets System Requirements: Second Life has specific spftware and hardware requirements. The following hardware and software is REQUIRED to run Second Life successfully. If your computer doesn’t meet these requirements, you may not be able to participate in Second Life: PC Minimum System Requirements:

   • Internet Connection: Cable or DSL
   • Operating System: Windows XP (Service Pack 2) OR Windows 2000 (Service Pack 4). NOTE: Second Life does NOT currently support Windows Vista
   • Computer Processor: 800MHz Pentium III or Athlon, or better
   • Computer Memory: 256MB or better
   • Video/Graphics Card: nVidia GeForce 2, GeForce 4mx, or better OR ATI Radeon 8500, 9250, or better

   Mac Minimum System Requirements:

   • Internet Connection: Cable or DSL
   • Operating System: Mac OS X 10.3.9 or better
   • Computer Processor: 1 GHz G4 or better
   • Computer Memory: 512MB or better
   • Video/Graphics Card: nVidia GeForce 2, GeForce 4mx, or better OR ATI Radeon 8500, 9250, or better

   For further information see Second Life – System Requirements.
   

2. Visit the Second Life Homepage and Go to the Join Now section where you will find an online form to fill out.
3. Choose a Name for Your New Avatar: You don’t need to use your real name… be creative. Choose a first name of your own creation, and a last name from a drop-down list of choices. As certain names reach a certain quota of residents,they drop off the list and new last names are added.
4. Choose from Some Basic Avatar Options: New users need to choose a basic setup for their new avatar. There are a number of male and female options on the website to choose from. (see right pic.) Don’t worry too much about this, as you will be able to modify and create your avatar later on.
5. Complete the Registration Form: Add the required details to the final registration form (name, password, email address etc) and submit. You’re pretty much signed up now and ready to go!
6. Optional:Premium Accounts or How to Get Linden Dollars to Spend in Second Life: If you’re interested in owning land or engaging in the Second Life economy, you may wish to sign up for a Premium accout. Premium account holders recieve a one-time grant of L$1000 in the Second Life currency ‘Linden dollars’, plus a weekly allowance of L$300. However – to join our tours in Second Life, you do not need to spend any money – simply skip this step.
7. Download and install the Second Life client: Users need to download and install the Second Life software onto their computer. (About 30MB for Windows users and 62MB for Mac users). You must have this software installed in order to access Second Life.
8. Log in to Second Life and Start Exploring!: That’s it! You’re ready to start your Second Life. Launch the Second Life software and login. You will arrive on Orientation Island where you you will be able to use the resources there to familiarise with the Second Life GUI.

For more information check out the Second Life Knowledge Base or the Second Life FAQ.

What is Second Life?

Developed by San Franciso based company Linden Lab and launched in 2003, Second Life is an online 3D virtual world currently gaining in popularity around the world. Much like massively multiplayer games, Second Life provides an immersive environment for users to play and interact in. However, Second Life goes beyond a game, allowing users or residents to build and create their own environments; and interact with others from around the globe.

Second Life allows users or ‘residents’ to come together to interact, play, learn, do business and communicate in an online environment which is 100% user owned and created. The platform provides tools which allow residents to build their own environments, create highly personalised avatars, clothes, vehicles and all sorts of amazing virtual objects.

Some of the important key features of second Life include:

• Customization of avatars – users can create highly detailed ‘virtual selves’
• A real life online economy – more than $5 million USD is transacted between users ever month
• Simple building tools which allow users to create almost anything they can imagine
• Scripting environment to create complex simulations
• Streaming audio and video from the web
• 100% user created content

In short, Second Life is an environment where users are designing, conducting business, building relationships, entertaining, learning, and living their virtual lives. Second Life residents can engage in rich, sensory experiences, authentic contexts, activities, and opportunities for reflection that form an exciting new domain for a range of educational applications including distance education, vocational and tertiary education and workplace training.