I've posted a number of times on the transition to 64-bit, we have release notes and a FAQ, as well as a number of tech notes for plugin developers, but in this post I want to cover how I see the community moving over to 64-bit.
64-bit is a fundamentally confusing issue - it's one of those things that should be totally transparent to computer users, but due to the nature of code and plugins, 64-bit is not transparent. So more explanation will hopefully at least not confuse the issue even more. Maybe.
Is a Transition to 64-bit Even Necessary? Does it Have to be Now?
The short answer is yes. 32-bit applications simply cannot take advantage of more than 4 GB of physical memory (among other limitations). Every year CPUs get faster, people get more cores, GPUs get faster, GPUs ship with more VRAM, and every now and then we even get a faster PCIe bus. During this time hard drive, SSD and RAM prices continue to fall. You can bring your computer up to 8 GB of memory (Crucial memory - good stuff!) for $34. But what's the point if the app you are feeding is 32-bit?
In other words, the march of hardware is unrelenting, and if we want X-Plane to be able to use the full power of our computers, we have to go to 64-bit.
How soon do we need to go to 64-bit? Mac users who like add-ons have been crammed up against that 32-bit ceiling for a while now, while Win 7/64 users mostly still have some headroom. But the real question is: could we finish out a major version run in 32-bit? Could we wait years to go 64-bit? I think the answer is no. Even if we didn't care about the RAM limit on Mac and Linux* 64-bit will become a Windows issue too; it's only a matter of time, and I suspect not that much time.
The Phases of Adoption
This is how I see the migration from 32-bits to a 32/64-bit world going:
- Beta. That's where we are now. In this phase, 64-bit technology is unproven even in the sim itself. Plugin developers are hopefully trying the 64-bit betas and looking for major critical bugs, but 64-bit isn't useful for actually flying. (Well, the sim is beta, and I never recommend flying on the beta.) I don't expect anyone to ship a 64-bit add-on during this phase.
- Crossover. Once X-Plane 10.20 goes final and we have a stable 64-bit build that third party developers can actually test against, we'll have a phase where some add-ons come out in 32/64-bit formats and others are not yet ported. The length of this phase will be the difference between the fast and slow add-on developers; different plugins will take different time to port, have different levels of complexity, etc. During this phase, users will have to pick 32-bit for compatibility or 64-bit for memory use.
- Acceptance. Eventually we'll arrive at a point where so many add-ons have been made 64-bit compatible that the norm and expectation is that all add-ons are 64-bit, and the community will mostly have to abandon add-ons that are not migrated forward.
Note that "acceptance" is not only after 10.20 goes final but there is an entire phase between 10.20 going final and being able to "just run all add-ons in 64 bit". This is because it is going to take time for people to move their plugins forward.
32-bit Still Works!
I cannot emphasize this enough: there is a 32-bit build of X-Plane in the 10.20 betas, and it should just work! The switch from 32 to 64 bits is not a binary transition where we pull the rug out from under everyone in one swoosh and everyone scrambles. It is the beginning of a migration that can happen over time, while 32 and 64-bit apps areboth available to everyone.
* I have heard people tell us that we don't care about the Mac just when it is surging, that we should drop everything but Windows, and that Linux is, in fact, the wave of the future. We're going to hedge our bets and keep supporting all three. Having done the work to be cross-platform it doesn't make sense to drop multi-OS support.