What's Adobe's 64-bit Flash plan?

64-bit versions of Windows, Mac OS X, and Linux now are in widespread use, and software for the operating systems is following suit. So it may seem a bit backward that Adobe withdrew its only 64-bit version of Flash Player.

But don't take the disappearance of Adobe Labs' experimental 64-bit Flash Player for Linux as a sign of things to come. Moving its widely used browser plug-in beyond the 32-bit era is a "top priority", said Tom Nguyen, Adobe's Flash Player product manager, last Saturday.

However, Adobe isn't committing itself publicly to a delivery schedule. And if it doesn't move with some alacrity, it risks inflicting broken Web sites on computer users who do make the 64-bit shift with their browsers.

Plenty of people would be perfectly happy to see Flash fade from the Web, ranging from those who resent how it enables intrusive advertisements to those who are actively working to reproduce much of Flash's abilities in Web standards such as HTML (Hypertext Markup Language) and CSS (Cascading Style Sheets). But there are also innumerable people who rely on Flash for online games, interactive charts, video streaming, and other uses. Those who switch to a 64-bit browser without a suitable version of Flash could find the Web doesn't work as they expect.

Making the 64-bit transition has been a long, grinding process for the mainstream computing industry, starting from the lowest levels of computing hardware and now moving through software. On personal computers, it began with processors--first from AMD, then from Intel. Operating systems were next to come along. Linux, with its technically savvy user base, made an early transition from 32-bit to 64-bit, and Apple made much of its 64-bit Mac OS X move with version 10.6, aka Snow Leopard. The larger population of Windows users have moved more slowly, but PCs running 64-bit Windows became commonplace with Windows Vista.

64 bits or bust
What does 64 bits get you? Mostly, the capacity for more than 4GB of memory in a computer or for a computing process, and in some cases, better performance. For memory-hungry chores such as video editing, a 64-bit machine is a necessity, but even with more mainstream computers running modern operating systems, it's useful.

The need for a 64-bit browser is less clear, though. Even with people doing ever more with browsers and with browser architectures that split computing processes up into separate memory compartments, 4GB goes a long way, and a 32-bit browser runs fine on a 64-bit operating system. "A 64-bit browser doesn't necessarily make the Web better or faster than an otherwise identical 32-bit browser," Nguyen said.

Here's one reason for 64-bit browsers, though: Apple said its Safari browser got a 50 percent performance boost running Web-based JavaScript programs when it made the 64-bit jump with Safari 4 in 2009. That's only one aspect of browser performance, but it's an important one.

Overall, from Adobe's perspective, it doesn't matter why people move to 64-bit browsers, only whether they are--and the likelihood is increasing that they will. One important milestone 64-bit Firefox, is expected later this year, and Microsoft's IE already is available in a 64-bit version. Google engineers have begun work on 64-bit Chrome, and that browser has Flash built in.

Adobe knows what's at stake. "As more people are using 64-bit operating systems, more will be moving to use 64-bit browsers, and it's important that they have the best possible Web experience," Nguyen said. "We are actively working on the release of a native 64-bit Flash Player for the desktop, and we will provide native support for Windows, Macintosh, and Linux 64-bit platforms in an upcoming major release of Flash Player."

Adobe has been willing to commit to some Flash developments, such as building support for Google's WebM video-streaming technology into Flash Player and putting it into the hands of a billion people within a year. But Nguyen didn't commit to a time for 64-bit Flash Player.

Gone, but not forgotten
Adobe answered Linux user demands for a 64-bit Flash Player with a pre-release version of the plug-in. But with the release of Flash Player 10.1 earlier this month, Adobe withdrew that product.

Why? "We have temporarily closed the Labs program of Flash Player 10 for 64-bit Linux, as we are making significant architectural changes to the 64-bit Linux Flash Player and additional security enhancements," Adobe said of the change.

What stands in the way of 64-bit Flash's return, and not just for Linux? Nguyen says it's not the core of the engine, but rather the supporting software:

The issue that comes to mind when going from 32-bit to 64-bit--the actual size of memory addresses--was addressed by our engineers some time ago. The main issue has been libraries. Flash Player relies on many code libraries for functionality like audio and video playback or hardware acceleration. If a library that Flash Player depends on isn't available in 64-bit, we need to rewrite code for new libraries. Flash Player is used to create powerful, beautiful apps and content, but it can also play back a wide array of media, from video clips back to Flash Player 6 to, say, the latest and greatest H.264 HD video streaming live with hardware acceleration. To do so natively in 64-bit, all of the many library dependencies must be available or rewritten for 64-bit. For example, on Mac OS X, we rewrote code that used the older Carbon libraries, which were 32-bit only, to instead use modern Cocoa libraries. Except for compatibility code we include for non-Cocoa browsers, Flash Player 10.1 is now fully rewritten for Cocoa, setting the stage for a 64-bit Flash Player.

That Mac situation is a sore point. Explaining why Apple banned Flash from the iPhone, iPad, and iPod Touch, CEO Steve Jobs castigated Flash for being insecure, crash-inducing, and a relic from a bygone age of computing.

Flash Player 10.1 answers some of those criticisms, for example with inclusion of multitouch support and the hardware acceleration for some Mac tasks. Hardware acceleration for decoding H.264 video, though, still doesn't exist for the Mac except in an experimental version of Flash Player called Gala.

Out of sync
Apple and Adobe are not in sync when it comes to Flash. After Adobe shipped 10.1, Apple released Mac OS X 10.6.4, which included Flash Player 10.0.45.2, though apparently those who had the newer version weren't downgraded, Nguyen said. To be fair, though, coordinating release schedules for complicated, heavily tested software isn't easy.

Safari is unusual in that it's been a 64-bit browser since Apple released version 4 in 2009. Plug-ins typically must match the browser they're plugged into when it comes to 32-bit or 64-bit designs, but Safari solves the problem with a compatibility later that accommodates 32-bit Flash, Nguyen said.

There are a lot of other browsers to reckon with, though, besides Safari. And Adobe may not have committed to a ship date, but the company sees the writing on the 32-bit wall.

"We expect 64-bit to be in wide use," Nguyen said, "and Flash Player will take advantage of native 64-bit."

This article was first published as a blog post on CNET News.