A Messy Transition: Practical Problems With 32bit Addressing In Windows
by Ryan Smith on July 12, 2007 12:00 PM EST- Posted in
- Software
Final Words
As we wrap things up, we'll reserve a few words for game & application developers who are working on projects that will hit the barrier. Supreme Commander is extremely disappointing in how it handles running out of addressing space. Ideally we'd like for it not to crash, but realistically we'd settle for just an error message pointing out that it hit the 2GB barrier so that we could quickly reach a solution. Otherwise seemingly-random crashes tend to be one of the hardest problems to resolve as a user. Developers need to take care here to offer some kind of warning when the 2GB barrier is the problem; not everyone is or will be well read on the subject or have the time to diagnose it, when it's actually an easily solvable problem.
Getting back to the point at hand however, we feel that this is only going to be the tip of the iceberg. As games and applications continue to come out that push the boundaries of computer hardware and run afoul of the 2GB barrier, these problems will only pick up in pace. For many power users this experience will be a common occurrence, and for most it will be a frustrating experience.
We're at the front end of a messy transition, one that may not end for several years. Today, 32bit games will hit the 2GB barrier, and tomorrow games with support for large addressing will hit the 3GB/4GB barrier. Not until 64bit versions of games are ubiquitous will we be completely through this transition, and that will still be a few years away.
Until that point, stories such as these will continue to be told as users unknowingly hit the 2GB barrier. Developers need to be doing a better job at handling the issue via better crash reports, but our inner cynic says that they can't be solely in charge of the matter. So it will be up to users to diagnose their own problems and take the appropriate action, be it switching operating systems and/or modifying executables. A little knowledge in this regard can go a long way.
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titan7 - Thursday, July 12, 2007 - link
There is nothing you can do. If you ship a game you could test it and ensure it doesn't run out of memory (e.g. GameCube has just 24megs of system memory and the last Zelda looked great. Quite a ways away from 2048megabytes PC games run into!), but what about a mod?When the application starts just allocate 512 megabytes or whatever you feel is reasonable. When new throws an exception free that memory, display a warning you're low on memory and need to upgrade to Vista64, and continue. When it new fails again one microsecond later you're screwed so display a message to the end user along the lines of "I told you so!" End users really like that type of thing. ;)
You could get a bit fancier by replacing all units with simple cubes or something, but all that does is delay in the inevitable a bit longer.
ncage - Thursday, July 12, 2007 - link
1) First step is to detect which OS you are using at startup. Is it 64 bit os or not?2) You SHOULD never code your application around a 2GB memory limit. It is very bad coding practice. Going through thorough examples in a short post like this isn't very practicle
3) Some higher level langauge/constructs abstract this away from you. For example if you are using .Net CLR you don't really have to worry about this unless maybe your doing some crazy pinvoke stuff which in most cases you shouldn't be doing anyways. Of course if your doing VB6 your never going to get around it anyways because vb6 is only 32 bit.
4) If you are doing C++ or assembly with windows then you can use the GlobalMemoryStatus() Function to Effectively see how much available address space you have.
Ryan Smith - Thursday, July 12, 2007 - link
The key to any of this is monitoring how much of the virtual address pool is in use; there should be an API call to ask Windows this. The easiest thing to do would be to give a warning at 1.9GB or so and then either do nothing, trigger a crash early, or attempt to reduce detail or flush space to stay below the 2GB barrier. The warning is the easy part, the hard part is preventing the crash, and I don't honestly believe anyone can or will be preventing crashing.yacoub - Thursday, July 12, 2007 - link
I just wish we had a better solution than Vista. Sure we can use 64bit XP but that's only going to last how much longer with full patch support from MS?If Vista wasn't such a pile and didn't perform worse in games when using equivalent hardware as the same system running XP, it wouldn't be such an unappealing alternative.
And even so, when running 4GB of RAM, how much over a LargeAddressAware flagged game with the 3GB boot.ini switch are you really gaining by using 64bit OS? Not much, really. We first need motherboards that are happy running 8GB of RAM, RAM cheap enough to buy 8GB for a reasonable price (which is not too hard with DDR2 2GB DIMMs right now), and do so at full performance/speed settings.
Really it's not just a move to a 64bit OS, it's also a move to 8GB of RAM.
OR it's simply having developers who code their games to work properly within 3GB of addressable RAM.
instant - Saturday, July 21, 2007 - link
How many more patches do you need for XP 64bit anyway?As long as the games work for it, why care about microsoft updating "security" hotfixes or not.
Tegeril - Thursday, July 12, 2007 - link
Articles like this make me very glad that I opted to go with 64bit Vista. All my hardware is supported at this point with stable drivers (we can argue the Creative X-Fi, but it works fine). I'm just amazed that people saw this coming and yet we have games that just die because of the problem. 64 bit isn't as bad as people make it out to be regarding compatibility :D - except iTunes and Quicktime :(halfeatenfish - Thursday, July 12, 2007 - link
How do the *nix variants deal with this same issue? Do they even have it? Can someone shed some light, especially in terms of OS X... Leopard, if anyone knows anything there. But Tiger info is just as good.titan7 - Thursday, July 12, 2007 - link
They all do the same thing for 32bit. Bu generally speaking *nix has been 64bit for years (decades) so if it is a problem just run the 64bit version of everything. And being more cross platform their code tends to have less hacks like you get in Windows apps that assume there is an extra bit available on every pointer. A single bit! Bah, we're talking about billions of bytes and elite programmers are trying to squeeze every last bit out of their application at the expense of future compatibility. LAME.The Boston Dangler - Thursday, July 12, 2007 - link
OSX is a 64-bit system, *nix ymmvMadBoris - Thursday, July 12, 2007 - link
Cool article Ryan. Good to see these issues getting more global attention.Since 32 bit seems it is here to stay for a lot longer than we want it to, and with software bloat continuing, this will hopefully continue to put pressure on driver devs to write better drivers that can handle >2GB addresses without issue. So that people can use the /3Gb switch without concern. I personally have never had problems with /3GB with any of my hardware/drivers but certainly 'less mainstream' drivers may not be handled with the care that they should be.
I like the breakdown of games/apps that support the LargeAddressAware flag, maybe this list can grow for future articles covering more apps/games. I also enjoyed your testing on the "potential" penalty of less kernel space, something I never took the time to do on my own.
Imagine my suprise today when making my rounds to my favorite hardware site. ;)