I'm new to the development world, primarily targeted towards game development, and I want to know more about how software becomes compatible across all architectures.
I've read information on the subject and there appears two ways that I have read:
-Compile the resources for the individual architectures.
-Have a Virtual Machine or interpreter run the application.
So it left me wondering about game content delivery systems like Steam, and how they handle this issue.
Does Steam have the resources compiled for each architecture and chooses between which one it sends to the client depending on the client's operating system and architecture?
Is there something else I'm missing?
How does software compatibility work? and how do developers (such as indie developers) overcome this issue?
Related
We are evaluating hospital automation softwares for a new hospital. In this hospital we plan to use thin clients on VDA OS. Most of the alternatives that we evaluate are web based. One of the alternative software is a good candidate for us thinking the functions of the software, price and company's support. However this application is designed in client-server architecture.
I am not familiar to VDI. I haven't used it yet. We just plan to use it for the hospital for the first time. I am not sure using client-server architecture is proper for thin clients thinking the performance of the system.
The number of users is important in this concept. We think that around 500+ users will exists. In VDI client (which is in reality stored in the server) every user will work as if he is working in its own pc. But in reality will connect to the server. Using an exe based program in this hardware architecture frightens me . The company says that using exe based program in this hardware architecture will not be a problem. But they don't have a reference working in VDA environment.
I need help in evaluating these hospital automation software from an expert :)
Thank you
I have a question about a family of softwares, of which one example is INtime, which lets you run a real-time operating system in parallel with Windows.
I have a reasonable grasp on how Windows works, including kernel/driver/application security rings etc. Similarly, I know how a RTOS runs on a dedicated system.
The Simple Question:
How do these go about existing together without fighting over hardware or other similar problems? How is the allocation or resources made, and how is this integrated with Windows?
Slightly more complicated:
What are the steps I would have to take if I wanted to develop something similar myself? Are there some open-source embodiment's of this paradigm I can inspect to glean some more understanding?
I am developing socket reading on an ActiveX EXE (i.e on a seperate thread).
How many sockets i can safely read independently?
I am working on windows XP OS.
I think this might be an operating system limit - I think I remember running up against a limit of 80 sockets on the XP machine I was using several years ago.
I would recommend that you abandon your effort and go with a commercial solution. I remember going down this path back in the 90s and running into a brick wall with ActiveX EXEs as far as threading goes. The thing is that ActiveX EXEs are apartment threaded, not free-threaded, so you don't get completely independent threads.
And doing server side threads properly is hard enough in modern languages, let alone ones that weren't designed for this purpose.
I ended up purchasing Server Sockets from Dart. Easily the best investment for that project. The performance is truly great - you are only limited by the system resources.
MSWINSCK.OCX is a very old way of doing things; it came with Visual Basic 6.0 and i remember using it way back when. i'm not sure the licensing on it... apparently it registers fine under 32-bit win7, but not 64-bit; here's a link to how to get it to register on 64-bit systems: http://angrybyte.com/windows-hacks/mswinsck-ocx-for-64-bit-windows-7-vista/
if you have an MSDN subscription or similar that gives you the ability to download the developer tools (bizSpark, etc. will do it too) then i believe that will also give you a license to redistribute the .ocx.
(btw, i don't actually remember the interface, but i seem to remember it being at least slightly more intuitive than the berkeley socket() interfaces.)
however, personal recommendation given your requirements: learn the APIs, there are lots of examples out there, and just write yourself a class that encapsulates them in a similar way as, say, the .NET Socket class... the APIs aren't that hard and i'm sure there's lots of help to be had here as well, and that's probably better than relying on something that's out-of-date like the control...
How do companies like Valve manage to release games to all three major gaming platforms? I am interested in the best-practices regarding code sharing specifically between Windows, Xbox360 and PS3, since the ideal solution is to reuse as much code as possible instead of rewriting the whole thing for every platform.
It's not any different than writing platform-independent code in other contexts. Hide platform-specific details (input, window interaction, the main event loop, threading, etc) behind generic interfaces, and test regularly on all the platforms you intend to support.
Note that the Cell's threading model is unusual enough that doing threading "generically" takes some care. I am not a Valve employee and I know none of their secrets, but it's my understanding that most game developers who want to target the PS3 use a job queue that the individual cell processors grab tasks off of as needed. This isn't necessarily the best way to use the Cell, but it generalizes nicely to more conventional threading models (like, frex, the one that thet PC and the 360 both use).
There's a bunch of Game Developer Magazine articles and GDC talks on the subject. In fact, since you mentioned Valve, they delivered a talk describing their approach at GDC08.
This is really a huge subject that I could (and have) talk about for hours upon hours, but elevator summary is:
Determine which parts of the engine are completely platform-specific and put them behind an abstraction. File and asset loading, for example, need to be rewritten for each console; but you can hide that behind an IFileSystem interface which provides a uniform API that the game code talks to.
The PS3 makes this hard because its abstraction point has to be someplace completely different from the other platforms. Even game features like collision and nav will have to be written differently for the Cell.
Try to keep leaf game code (entities, AI, sim) as platform-agnostic as possible...
But accept that even the leafiest of game code will sometimes need some platform-specific #ifdefs for perf or memory or TCR reasons. A lot of UI will have to be rewritten because the manufacturers have conflicting certification requirements.
Anyone who says the words "I'm not worried about performance" or "memory isn't an issue" shouldn't be on the payroll.
This question can be divided up into two separate questions. "How can I write portable code?" and "What are the divergent requirements of mainstream gaming platforms?".
The first question is relatively easy to answer. Best practices for abstracting your non-portable code are covered in Write Portable Code:
http://books.google.ca/books?id=4VOKcEAPPO0C&printsec=frontcover
Turning theory into practice, the Quake 3 source code does a pretty good job of dividing out different platforms into separate areas for a C codebase, available at http://www.idsoftware.com/business/techdownloads/ However, it does not demonstrate C++ patterns such as abstract interfaces, implemented once per platform.
The second part of your question, "What are the divergent requirements of mainstream gaming platforms?" is tougher. However, it is notable that your largest areas of change are still your renderer, your audio subsystem and your networking.
Each console platform has a series of certification requirements, available under an agreement with the respective console owners. The requirements drive consistency in user experience and are not focused on gameplay or qualitative, high level issues. For instance, your game may need to display a reasonably interesting animating loading screen, and black screens are unacceptable.
Getting your hands on this documentation as soon as possible is key to making the right choices in developing for a specific console platform.
Finally, if you can't get your hands on a console devkit, I suggest you port your code to the Mac from Windows. The Mac gets you an OS port ensuring you are not tied to Windows as well as a processor port if you support universal binaries. This ensures your code is endian agnostic.
If you support both PC and Mac, you will be well positioned to support a third platform, should you gain access to it in the future.
Addendum You wrote:
the ideal solution is to reuse as much
code as possible instead of rewriting
the whole thing for every platform
In many game porting scenarios, the ideal solution is not to reuse as much code as possible, but to write the optimal code for each platform. Code can be reused between projects and is relatively inexpensive as compared to the content that the engine takes in. A more reasonable goal is to aim for lowest common denominator content that runs on all platforms without modification (a build phase that packs the content for media is okay).
It's great to do simultaneous development. You find all kinds of bugs you wouldn't find doing just one platform.
I remember that programmers in DOS had null pointers all the time because writing to low memory didn't immediately crash them. When you ported to an Amiga, Atari ST, or Macintosh, boom! I remember telling a DOS programmer that he had a couple null pointers on an aready-shipped game. He thought for a couple seconds and grinned, "That explains a few things."
Now that games have such large budgets, it's important to ship them all at the same time so you don't waste marketing and ad budgets.
My advice on simultaneous development is to pick one lead platform, but never let the other platform(s) get more than a week behind. It will become obvious as you program which parts of the code are common to all platforms and which are different. Pull out the differences into one or more platform-specific areas.
My experience is in C/C++. It's a bigger problem if you have to port against different languages (say, Java and Objective-c).
A few years ago the Opera CEO said in an interview that the key to developing for independent platforms is to move away from any single OS/platform libraries. He went on and said that they developed their own libraries that improve OS performance.
My assumption is that big companies will have a common, Xbox, PS, windows, FooOS, separate teams. Each platform needs to be tweaked differently and requires different implementation methods. I don't think they do one source for all platforms; rather, they build one for each OS thereby, improving efficiencies. I remember EA used to release some console games earlier than the PC versions and vice versa.
Another issue is that different consoles have different hardware thus requiring different programming techniques.
there are two extremes, build one source that fits all (java for instance) but you run the risk of inefficiency or write 40 versions; one optimized for each platform
Back when I had a friend into educational computer games (before The Learning Company gutted the field), he was a great fan of creating cross-platform libraries for doing everything.
This is easier for games than other apps. If you have a word processing app to run on the Mac and Windows, for example, it really does need to look and behave like a Mac app on the Mac, and a Windows app on Windows. Write a game, and it doesn't have to conform to the native behavior, look, and feel.
If you want open source examples, you could look at source code of Quake 1, 2 and 3 engines. They are structured quite portably. (Of course, no ps3 or xbox360 support, but same principles apply)
http://www.idsoftware.com/business/techdownloads/
The Free MS Windows replacement operating system ReactOS has just released a new version. They have a large and active development team.
Have you tried your software with it yet?
if so what is your recommendation?
Is it time to start investigating it as a serious Windows replacement?
Targeting ReactOS specifically is a bit too narrow IMO -- perhaps a better focus is to target compatibility with WINE. Because ReactOS shares so many of its usermode DLLs with WINE, targeting WINE should result in the app running just fine on ReactOS.
Of course, there will always be things that WINE can't emulate well (hence the need for ReactOS). In this way, it seems that if something runs in WINE, it will run in ReactOS, whereas the fact that something runs in ReactOS doesn't mean that it will necessarily run in WINE.
Targeting WINE is well documented, perhaps easier to test, and by definition, should make your app compatible with ReactOS as a matter of course. In this way, you're not only gathering the rather large user base of current WINE users, but you're future-proofing yourself for whenever anyone wants to use your app with ReactOS.
In their homepage, at the Tour you can see a partial list of office, tools and games that already run OK (or more or less) at ReactOS. If you subscribe to the newsletter, you'll receive info about much more - for instance, I was quite surprised when I read most SQL Server 2000 tools actually work on ReactOS!! Query Analyzer, OSQL and Books Online work fine, Enterprise Manager and Profiler are buggy and the DBMS won't work at all.
At a former workplace (an all MS shop) we investigated seriously into it as a way to reduce our expenditure in licenses whilst keeping our in-house developed apps. Since it couldn't run MSDE fine, we had to abandon the project - hope in the future this will be solved and my ex-coworkers can push it again.
These announcements might as well be also on their homepage - I couldn't find them after 5 mins. of searching, though. Probably the easiest way to know all these compatibility issues is to join the newsletter, or look for its archives.
I have been tracking this OS' progress for quite some time. I believe it has all the potential to really bring an OSS operating system to the masses for it breaks the "chicken and egg" problem: it has applications and drivers from the very beginning (since it aims to have full ABI compatibility with MS Windows).
Just wait for their first beta, I won't be surprised if they surpass Linux in popularity really soon after that...
Post Edit: Found it! Look at section Support Database, it's the web place to go look for whether a particular piece of hardware of some program works on ReactOS.
ReactOS has been under development for a long long time.
They were in some hot water earlier because some of their code appeared to be line by line dissasembly of some NT kernel code, I think they have replaced all of it.
I wouldn't bother with cross platform testing until they hit the same market penetration as Linux, which I would wager is never.
Until ReactOS doesn't randomly crash just sitting there within 5 minutes of booting, I won't worry about testing my code on it. Don't get me wrong, I like ReactOS, but it's just not stable enough for any meaningful testing yet!
No, I do not think it is time to start thinking of it as a Windows replacement.
As the site states, it's still in the Alpha stages. More importantly, whos Windows replacement? Yours? Your users? The former is one thing, the latter is categorically a no-go.
As an aside, I'm not really sure who this OS is targetting. It has to be people who rely on Windows software but don't want to pay, because people who simply don't want Windows can use MacOS / Linux, and the support (community or otherwise) for these choices is good.
Moreover, if you use Linux you already have some amounts of Windows software support via Wine.
Back to people who rely on Windows software but don't want to pay. If they are home users they can just simply pirate it, if they are large business users they already have support contracts and trained people etc. It's hard enough for large businesses to be OK to update to new versions of Windows, let alone an open source replacement.
So I suppose that leaves small businesses who don't want to obtain illegal copies of MS software, can't afford the OS licences and rely on software that only runs on Windows and has bad of non-existent Wine compatibility.
It is a useful replacement for Windows when it runs 'your' software without crashing. At the moment it is not a general purpose os as it is too unstable (being only alpha) but people have used ReactOS successfully in anger for specific tasks already. As a windows replacement it has multiple potential uses, sandbox systems, test and development systems, multiple virtual instances, embedded devices, even packaging/bundling legacy apps with their own compatible o/s. Driver and application compatibility, freed from Microsoft's policy of planned obsolescence and regular GUI renewal, what's not to like?