After years of rumours of a Google phone, the search giant finally unleashed its mobile play: an alliance of handset makers and an open software platform dubbed Android.

Google released the software-developer kit, or SDK, for Android and announced that it would set aside $10m to give out as prizes to developers who create programs for the new platform.

Android is based on the work of Andy Rubin and several other founders of Danger. Google acquired their newer venture, Android, in 2005.

Rubin, director of mobile platforms at Google, talked to ZDNet Australia sister site CNET News.com about what Android phones will look like, whether they will compete with Apple's iPhone, and why the software took so long to build.

Q: What does Android look like?
A: Google has stepped up on behalf of the alliance to do various components of the support from a developer community perspective. We have a user interface team continuing development on the UI, and there will actually be a replacement UI.

We've been building it as a mobile mashup platform. That is a new concept for [mobile] phones. So the developer can now stand on the system platform and take advantage of other developers' work for the first time. So, that just creates more flexibility for the developers, less work, faster turnaround, rapid prototyping, and all that stuff, and we're really, really excited about that concept.

Is there a prototype dubbed Dream? Who has it, and when are we going to see it?
I actually don't know where that name come from. That's been an internal codename that's been kicked around here, but it changes quite constantly.

We have manufacturing partners in the alliance, and they're building products, and Google has been given some of those devices. As part of the SDK, there's a complete hardware emulator that runs on the PC. It runs on Mac, Windows and Linux. It's literally a hardware emulator of various devices -- you know, different screen formats: horizontal, landscape, or portrait and, with the Qwerty keyboard and without a Qwerty keyboard; with touch, without touch.

But consumers won't see devices until next year, right?
That's right.

So, will there be a Google phone?
I'm going to say "no comment" on that.

Why did you pick Linux as the foundation for Android?
One of the advantages of Linux is, it's a pretty prevalent operating system. The portion of Linux that we use for Android is just the kernel portion, and the benefit of kernel, of course, is that it's been already ported to all the varieties of semiconductors that run in [mobile] phones.

Why don't you join an existing Linux phone effort, such as the LiMo Foundation, or the Lips (Linux Phone Standards) Forum?
One of the key differences in the Open Handset Alliance with some of the existing consortiums is that we're actually building a product. Every member of the alliance has contributed something to the effort, and it's very product-focused.

A lot of industry efforts just write specifications, and then they expect the rest of the industry to meet those specifications when they build their product.

What were the design goals for the Android project? What do you want Android to do that can't be done with Symbian, Windows Mobile, OS X, Palm OS?
Openness. The platform is completely open in a variety of ways. Of course it has open APIs, but it's also open source, and it being open source means it's [open to inspection]. So expect to have the entire industry crawling all over the source base, trying to make sure that there aren't security issues, and there aren't inefficiencies in how the platform is designed.

Who will do the technical support for Android?
Within the alliance, there are five categories: semiconductor companies, OEMs (original equipment manufacturers), carriers, software companies, and commercialisation partners. The commercialisation partners will do the support.

What's Google's business model for Android? Assuming that it's free to use, where is Google's return on investment?
Google's mission is to organise the world's information and make it universally accessible and relevant. This Android project satisfied the universal-access component of our mission.

We need to make sure that on [mobile] phones everywhere, consumers who carry them throughout their day have access to Google services.

Does advertising play into this at all?
There is no direct-advertising component in the platform. [But consumers will be able to] access advertising the same way you're doing on your desktop PC through the browser.

Will the browser in Android be tied to the platform, or can I use any mobile browser I like?
You can use any mobile browser you like.

What were the primary development challenges for Android? Did you design it with high-end or mainstream hardware in mind, and what are the system requirements?
When we built the system, we wanted it to be as flexible as possible. We did a lot of work to write our own library, and it's 250KB, not 3.4MB.

We took a lot of those types of considerations when we were developing the platform. The platform is capable of running, as I said, on kind of mid to lower-end devices as well.

We feel that one of the platform's distinguishing features is how it handles access to data. I talked about the mashups on the Internet and everything else. So, although the platform can run in a stripped-down fashion on mass market phones, we think that the initial devices will be mid to higher-end phones just because of the data access capabilities of the platform.

The minimal requirements are 32MB of RAM, 32MB of flash, and a 200-megahertz online processor. There are companies within the alliance working to bring that to even lower-power phones.

Will there be different versions of Android devices where there will be a commonality, or a basic level of compatibility, that they all must maintain for applications to run on them?
It's really important that we don't create a fragmented environment, and one of the complaints I think developers have with open source is that there is really no way to guarantee compatibility.

In the SDK, there is a scripting engine that allows remote test scripts to be run on the emulator on a phone. Also, there is a secondary compatibility [test for] support for services.

It's important for third party developers to make sure that the applications run across different phones. There's not going to be a hard certification requirement. That doesn't make sense in an open environment. But we'll provide the tools necessary to make sure that these applications can be made compatible, if that's what the industry wants.

The platform itself has the ability to be targeted toward all sorts of different screen sizes and input mechanisms -- touch devices, trackballs, five-way keypads, portrait displays, landscapes, big displays, small displays, Qwerty keyboards, non-Qwerty keyboards. When the developer... ...writes an app, and that app is on portrait display, the platform also will run that same app on a landscape display.

What other types of devices that aren't exactly [mobile] phones could Android enable or run on?
The sky is the limit. This platform has been contemplated in different devices, from car-navigation systems to set-top boxes to laptop computers and, of course, [mobile] phones.

One of our alliance partners, Intel, has a category device called MID, or Mobile Internet Device, which is somewhere between a [mobile] phone and a PC. It's a large-display device meant to be primarily an internet access device.

Will Java be the primary foundation for software running Android?
Yes.

What are the lessons you learned from Danger?
I learned a lot of things.

One of the things I learned is it's getting easier and easier for people to build [mobile] phones. In 2009, there will be single-chip [mobile] phones, so you can go to Qualcomm and get basically a phone and a chip, or to Broadcom or one of the other alliance partners.

Pretty much anybody now can build a [mobile] phone right, and I mean anybody. The big lesson I learned coming out of Danger is, let's figure out a way to take advantage of that and provide a solution for the hardest part, which is the ever-changing software component.

The Sidekick became a cult hit. What limited its adoption?
I don't think it has limited adoptions, but it's probably best to ask the folks at Danger that question. I've been out of the company for about four years now, so I feel like I'm a little out of touch.

How would Android be different if you hadn't sold the company to Google?
It would have taken me a lot longer to do what I did as a start-up company. The platform within Google has a broader chance at success. Within Google, I think we have the opportunity to pretty quickly accelerate it and push it into different areas.

How have your visions of mobile phones changed since the Sidekick was invented?
The [mobile] phone industry has so much legacy software today. One of the great things about starting from scratch is, you get to re-evaluate the importance of the legacy. And you can make decisions about which parts of it you want to support and which parts just don't make sense.

So the part that I think becomes really important is more around the heavy lifting that you can do in the cloud. ["The cloud" refers to data residing on a server on the Internet that anyone with a computer and an internet connection can access.] Remember, the cloud didn't exist when the internet didn't exist -- when [mobile] phones first were introduced. So that's part of the game that changed.

Do you think the big US carriers -- AT&T and Verizon Wireless -- will join the Open Handset Alliance?
It's certainly possible. The alliance is completely open. It's not a closed thing; it's not a club. We welcome anybody. Members who wish to join the alliance actually have to contribute something, so I encourage people to join and contribute.

When did the work on Android start, and why did it take until now?
Why did it take until now? Because it was a ton of work. How often have you seen a completely new operating system come to market? It doesn't happen that often because there's just so much [required] to build an operating system these days.

Remember, Android is not just an operating system. The Alliance put everything on top of the operating system necessary to build a [mobile] phone. We built a Web browser, and we built e-mail applications, and we built a Google Maps application.

How strategically significant is the mobile market for Google?
I would say very. There are close to three billion [mobile] phones out there today. They are pervasive. They're intimate. You bring your phone with you wherever you go. So it has a lot of touch points in your life because it's in your pocket with you most of the time.

That is super important to Google. This is just going to be, for some people, the first way to get access to the Internet. They might not even have a PC. So it is the future.

Which is more important to you: the richness of the platform or the affordability of phones the platform runs on?
I would say both are equally important, and that is the reason we made this an open-source project. By having a free and open platform, we're reducing the cost of software, which, in turn, reduces the cost of the [mobile] phone. When we built the platform, we didn't go for the really expensive US$600 smartphones. We went for the mid-market.

What do you think of the iPhone?
I love it. I use it every day. That's my phone, and I think it's a great product. It's probably the best version 1.0 piece of consumer electronics that I've ever used.

Do you think that the Android devices are going to be competing with the iPhone?
No, I do not. I think it's a different business. Apple has a great business in building really, really high-quality consumer products, and the platform that we're building can go into a lot of different products.

What have we not discussed that we should?
I'm really proud of the team that came together to create this, both internal to Google and within the alliance. It set a precedent of co-operation.

When you build an alliance of 34 companies in an industry like the mobile industry, and you get them all to work together to produce something as functional and as high-quality as Android, it's a completely new model.

I'm really proud of the way it turned out. I'm really excited about the possibilities that open up in the industry.