For example, are they using Java/Struts? Or ASP.NET? Or PHP? Or some combination of technologies?
Not sure how public they are about their infrastructure, but it would be very interesting to know what they use.
Not sure if this is what you are looking for, but see here: http://en.wikipedia.org/wiki/Second_Life#Technology
As is often the case with such questions, High Scalability has an overview of the Second Life architecture, plus links to presentations by SL staff and other resources.
I will take a wild guess, a combination of scripts running on a server written in C++.
While this is an antique question, I'm surprised that no one mentioned OpenSimulator or some other Sim application. OpenSimulator will allow you to run your own Second Life clone on your own hardware and with one of the many SL viewers that are out there, you could just connect to your own virtual world. And this World would be very similar to SecondLife, including it's scripting language!
OpenSimulator is written in C# back in 2007 using the Second Life Protocol to be very identical, although they don't strive for complete compatibility.
The Firestorm Viewer is also open source as Linden Labs once published the source code of their viewer using an LGPL license. But the Firestorm team doesn't make access to the source code easy to find. (It is here!) You will need to know C++ to understand the code.
So, Second Life is made from three parts: Server, client and a special protocol that goes in-between. As Second Life is old, it also uses some older techniques and protocols as developers generally don't fix things that aren't broken. Then again, this question is also old and I'm not even sure if anyone is still interested in Second Life.
Still, if someone is still interested then this gives some nice additional information.
Related
I know a lot of questions have been asked about VB6 migration (and I've read most of them), but I'm still not entirely certain on what the best way to go about this is.
We have a client that we built an order tracking application for about a decade back and they came to us this week saying they were having some issues with it. The app was written entirely in VB6, which has been something of a hassle as tracking down the necessary tools to work with a project so old took some considerable effort. In an effort to make any future maintenance less of a headache, my boss wants to pitch the idea to them of updating the app to .net and wants to know what exactly that would entail. I've never done anything like this before, but what I've read (both here and elsewhere) suggests that Microsoft's "auto-update" from VB6 to .net simply doesn't work very well and I'd pretty much have to rebuild the app from the ground up.
To get to the crux of my question: is this the case? Would I pretty much just need to rewrite it, or is there another means of going about this that could/would save me a lot of time/effort?
Any insight would be greatly appreciated.
VB6 and VB.NET are radically different. The syntax has changed, and so has the underlying structures, forms, custom controls, and almost every single aspect you can possibly think about.
A complete redesign and reassessment of needs and functionality is imperative. With .NET the plethora of new libraries and features supersede the antiquated VB6 libraries, OCXs, etc. Also if you feel bold, you can migrate your code to C# and other CIL languages aside from VB.
Out of hand, the Microsoft migration tool will not do much. Moreover, it also depends on whether you have your business logic well separated from your GUI. Otherwise, it will make it even harder. Depending on the size of your application, it might make it quite expensive. Another possible solution you might consider is to run your app in a virtual environment or on a remote app http://technet.microsoft.com/en-us/library/cc730673(v=ws.10).aspx that will ease the deployment pain.
I have also researched this topic.
Try the smart rewrite solution that converts 95% of the code automatically.
first, run your app through the assessment wizard to determine estimated costs and resources needed.
http://visualwebgui.com/Gizmox/Solutions/InstantbCloudmoveb/tabid/744/Default.aspx
I've been looking for first-hand information on the World of Warcraft addon API. There are a couple wikis that are pretty good, but their reference links only point internally. Surely there is some information published by Blizzard on the topic.
Can all of their information really be gleaned from reverse-engineering and forums? That would be hard for me to believe.
Its not all necessarily gleaned from inspection or trial and error. Some is provided, but randomly, from "heads up" posts in the forums from "the source", as in Blizzard employees. They are usually pretty good about it, though is almost always provided in a "just the essentials to save you some pain" sort of way.
Here's an example:
http://blue.mmo-champion.com/topic/233590-mop-changes/
Watching for the "Blue" posts goes a long way, and its been this way for a long time. If you look at someting like this (old 3.1.0 end user patch notes) http://us.battle.net/wow/en/game/patch-notes/3-1-0 , and then scan to near the bottom there will be a note and link for API changes, so its easy to glean their intent on this, and that they intend to provide some "unofficial" support about API changes there whilenot burdening the actual product readme with them.
In general, I'd say that due to the very open nature of the materials, the source for the UI, very little is hidden and most is pretty self-evident, so it sort of barely qualifies as reverse engineering. Once you understand the Lua relationship to the general design of the WoW UI and supporting API, it's much easier.
As for the implied question about "why", the "hard to believe" part. They are doing, in my estimation, what they believe is the best balance between fully supporting without "officially" suporting, and not wasting cycles trying to document a huge amount of available facilites thats ever changing. I think they belive it makes a better product, having the ability to customize, so its intheir interest, however is frought with problems and even legal issues from many angles to be expressly "official" about it or to try to maintain coherent docs.
----
Toward the question "git hub" below, here is the "blue" post in context, which can be found by clicking the "blizz" link icon on the mmo-champion link provided before: http://us.battle.net/wow/en/forum/topic/6413172918#1 I was trying to give an example of a Blue post that had detail, but I accidentally gave one for the Web API not the Game API. However the principle is the same, and provides more Blizzard to Community context for dev support.
So basically that particular post was in reference to changes in the Web API, and the Git remark has no relevance to the game UI Customization and Macro thing. There is no hidden or official doc source for game UI Customization and Macro. Mostly its because it simply doesnt exist for anyone. :)
Yes, all the information is gleaned from the source.
Blizzard doesn't post the API information at this time, AFAIK.
http://www.wowpedia.org/Portal:Interface_customization is likely to be your best resource.
There are multiple ways to discover the names of callable C functions exported into the Lua environment.
But yes. One quite simple one would be to enumerate all the globals in the source that are written to, then enumerate the globals that are exposed while WoW is running - and take the difference, perhaps limiting the result to globals of type 'function'
Blizzard used to informally document its API for a while, but it has always been 'unsupported'
There are other ways to discover the API - but they involve doing things which may violate the TOS.
There is a website now that contains the API for wow addons. This has been helping me a lot.
I'm quite new to the field of computer science but I think I've got a pretty decent idea for a website to aid classroom CS learning and collaboration. I'd really like to develop the website from the ground up and make it a sort of pet project in hopes of eventually getting it out on the web for free. Hopefully I can get some teachers to adopt it for use with their classes.
The problem is that I honestly don't know where to start. I've got the idea but I don't have enough formal education to guide the implementation of my idea. The site should have quite a bit of functionality in the long run. I'll need to be able to store user and class data/files as well as offer discussion boards and other things.
Without getting into too many details, what is the best way for me to get started? What languages and databases should I be most interested in as I build the site and ensure scalability and future functionality developments? I would really appreciate any information you could give me on how to structure the project/stack as I don't have much of a clue at this point. I have the idea. Now I just need a little bit of help getting started.
Thanks!
There are definitely already projects out there that will (more than likely) do everything you're currently considering. That said, there's immense benefit in doing a project like this for personal development - you get to learn, and you expand your public portfolio. If you run the project as open source, you can also demonstrate your ability to work with others. All very good (hireable) attributes.
Are there any programming languages you already know? Are there any that your course is going to be teaching that you know ahead of time?
There are so many different languages and frameworks available to choose from, but I'll only mention a few.
Language: Framework
.NET: ASP.NET MVC
python: django
ruby: ruby-on-rails
I'm a huge fan of django. Python is quite a nice language to learn. I'd recommend django purely from a biased point of view. Python runs on Windows, Linux, and Mac, though you probably don't want to host python on windows (culture more than ability).
Conversely, if you really like Windows, ASP.NET MVC makes building out websites very very easy. Mono does allow you to run .NET on linux and mac, but you might find support lacking, and I wouldn't suggest using Mono for your first project.
PHP is (was?) another popular language for building websites in. There are tonnes of web frameworks available for PHP. Popular opinion seems to be that PHP makes it easier for developers to write bad code, though it is possible to write good code with PHP.
Unfortunately, without knowing a rough direction in which you're headed, it's nearly impossible to offer some concrete advice. Database choice will generally come down to what language and platform (linux/.net) you're targeting. Web server also fits this profile. Once you decide on a language, narrowing down the other choices become a lot easier.
Learn HTML to start with and keep improving as per needed with css , javascript. You won't need more then this.
I am looking to start developing a relatively simple web application that will pull data from various sources and normalizing it. A user can also enter the data directly into the site. I anticipate hitting scale, if successful. Is it worth putting in the time now to use scalable or distributed technologies or just start with a LAMP stack? Framework or not? Any thoughts, suggestions, or comments would help.
Disregard my vague description of the idea, I'd love to share once I get further along.
Later. I can't remember who said it (might have been SO's Jeff Atwood) but it rings true: your first problem is getting other people to care about your work. Worry about scale when they do.
Definitely go with a well structured framework for your own sanity though. Even if it doesn't end up with thousands of users, you'll want to add features as time goes on. Maintaining an expanding codebase without good structure quickly becomes fairly horrible (been there, done that, lost the client).
btw, if you're tempted to write your own framework, be aware that it is a lot of work. My company has an in-house one we're quite proud of, but it's taken 3-4 years to mature.
Is it worth putting in the time now to use scalable or distributed technologies or just start with a LAMP stack?
A LAMP stack is scalable. Apache provides many, many alternatives.
Framework or not?
Always use the highest-powered framework you can find. Write as little code as possible. Get something in front of people as soon as you can.
Focus on what's important: Get something to work.
If you don't have something that works, scalability doesn't matter, does it?
Then read up on optimization. http://c2.com/cgi/wiki?RulesOfOptimization is very helpful.
Rule 1. Don't.
Rule 2. Don't yet.
Rule 3. Profile before Optimizing.
Until you have a working application, you don't know what -- specific -- thing limits your scalability.
Don't assume. Measure.
That means build something that people actually use. Scale comes later.
Absolutely do it later. Scaling pains is a good problem to have, it means people like your project enough to stress the hardware it's running on.
The last company I worked at started fairly small with PHP and the very very first versions of CakePHP that came out (when it was still in beta). Some of the code was dirty, the admin tool was a mess (code-wise), and sure it could have been done better from the start. But do you know what? They got it out the door before their competitors did, and became extremely successful.
When I came on board they were starting to hit the limits of their current potential scalability, and that is when they decided to start looking at CDN's, lighttpd caching techniques, and other ways to clean up the code and make things run smoother when under heavy load. I don't work for them anymore but it was a good experience in growing an architecture beyond what it was originally scoped at.
I can tell you right now if they had tried to do the scalability and optimizations before selling content and getting a website live - they would never have grown to the size they are now. The company is www.beatport.com if you're interested in who I'm talking about (To re-iterate, I'm not trying to advertise them as I am no longer affiliated with them, but it stands as a good case study and it's easier for people to understand what I'm talking about when they see their website).
Personally, after working with Ruby and Rails (and understanding the separation!) for a couple of years, and having experience with PHP at Beatport - I can confidently say that I never want to work with PHP code again =p
Funny to ask "scale now or later?" and label it "ruby on rails".
Actually, Ruby on Rails was created by David Heinemeier Hansson, who has a whole chapter in his book labeled "Scale later" :))
http://gettingreal.37signals.com/ch04_Scale_Later.php
I agree with the earlier respondents -- make it useful, make it work and get people motivated to use it first. I also agree that you should pick off-the shelf components (of which there are many) rather than roll your own, as much as possible. At the same time, make sure that you choose components for your infrastructure that you know to be scalable so that you can go there when you need to, without having to re-write major chunks of your application.
As the Product Manager for Berkeley DB, I've seen countess cases of developers who decided "Oh, we'll just write that to a flat file" or "I can write my own simple B-tree function" or "Database XYZ is 'good enough', I don't have to worry about concurrency or scalability until later". The problem with that approach is that a) you're re-inventing the wheel (and forgoing what others have learned the hard way already) and b) you're ignoring the fact that you'll have to deal with scalability at some point and going with a 'good enough' solution.
Good luck in your implementation.
Let's say that you have to implement some functionality that is not trivial (it will take at least 1 work week). You have a SDK/API/library that contains (numerous) code samples demonstrating the usage of the part of the SDK for implementing that functionality.
How do you approach learning all the samples, extract the necessary information, techniques, etc. in order to use them to implement the 'real thing'. The key questions are:
Do you use some tool for diagramming of the control flow, the interactions between the functions from the SDK, and the sample itself? Which kind of diagrams do you find useful? (I was thinking that the UML sequence diagram can be quite useful together with the debugger in this case).
How do you keep the relevant and often interrelated information about SDK/API function calls, the general structure and calls order in the sample programs that have to be used as a reference - mind maps, some plain text notes, added comments in the samples code, some refactoring of the sample code to suit your personal coding style in order to make the learning easier?
Personally I use the prototyping approach. Keep development to manageable iterations. In the beginning, those iterations are really small. As part of this, don't be afraid to throw code away and start again (everytime I say that somewhere a project manager has a heart attack).
If your particular task can't easily or reasonably be divided into really small starting tasks then start with some substitute until you get going.
You want to keep it as simple as you can (the proverbial "Hello world") just to familiarize yourself with building, deploying, debugging, what error messages look like, the simple things that can and do go wrong in the beginning, etc.
I don't go as far as using a diagramming tool sorry (I barely see the point in that for my job).
As soon as you start trying things you'll get the hang of it, even if in the beginning you have no idea of what's going on and why what you're doing works (or doesn't).
I usually compile and modify the examples, making them fit something that I need to do myself. I tend to do this while using and annotating the corresponding documents. Being a bit old school, the tool I usually use for diagramming is a pencil, or for the really complex stuff two or more colored pens.
I am by no means a seasoned programmer. In fact, I am learning C++ and I've been studying the language primarily from books. When I try to stray from the books (which happens a lot because I want to start contributing to programs like LibreOffice), for example, I find myself being lost. Furthermore, when I'm using functionality of the library, my implementations are wrong because I don't really understand how the library was created and/or why things need to be done that way. When I look at sample source code, I see how something is done, but I don't understand why it's done that way which leads to poor design of my programs. And as a result, I'm constantly guessing at how to do something and dealing with errors as I encounter them. Very unproductive and frustrating.
Going back to my book comment, two books which I have ready from cover to cover more than once are Ivor Horton's Beginning Visual C++ 2010 and Starting Out with C++: Early Objects (7th Edition). What I really loved about Ivor Horton's book is that it contained thorough explanation of why something needs to be done a certain way. For example, before any Windows programming began, lots of explanation about how Windows works was given first. Understanding how and why things work a certain way really helps in how I develop software.
So to contribute my two pennies towards answering your question. I think the best approach is to pick up well written books and sit down and begin learning about that library, API, SDK, whatever in a structured approach that offers real-world examples along with explanations as to how and why things are implemented as they are.
I don't know if I totally missed your question, but I don't think I did.
Cheers!
This was my first post on this site. Don't rip me too hard. (: