and . PCMag will have far more to say in the coming days and weeks about the quality and performance of Microsoft's Windows 7 OS, as well as how it stacks up against its primary competition, Apple's . But have you ever wondered what it would be like if you could watch executives from both companies really have at it? Not with snarky commercials, but with an honest discussion of the technologies that drive these operating systems? It won't happen, of course, but this is pretty close.

A couple of weeks ago, I got a surprise offer: Apple wanted to go on record and talk about why Snow Leopard is better than Windows 7. Apple's Senior Director of gave me his side of the story. Then I interviewed Microsoft's Jay Paulus, Director, , to let him make his case. Although the interviews were conducted separately, I've tried to blend the comments to make it something of an ex post facto debate. It seems fair enough, as each side knew I would be talking to the other. What I ended up with is a good-old-fashioned debate, in which I play the moderatorand occasional fact-checker. It may not settle the question of which OS is better, but goes into a lot more technical detail than the 30-second spots that will be all over TV this holiday season.

Editor's Note: To reiterate, the interviews with Mr. Croll and Mr. Paulus were conducted separatelyat no time were all three parties speaking to each other at the same time, and while they did respond to these topics and questions, I have added some detail to my moderator sections in order to put Mr. Croll and Mr. Paulus' responses in the proper context.

The 64-Bit Question

Let's start with 64-bit. For perhaps the first time in operating system history, average consumers are aware of the 64-bit choice and thinking about whether or not they need or want to use it. Mr. Croll, what does Apple bring to the table here?We have one version of Snow Leopard. Contrast that to Windows, which has and adds a lot of complexity. Their product matrix gets really complex very fast. Then multiply by two, because you have to know if you want 32- or 64-bit.

In 2003, we started adding 64-bit technology. Apple went from a 32-bit to 64-bit environment without any issues for customers. Now we can allow 64-bit apps to run entirely on a 64-bit Intel processor. The major system apps now run in 64 bits. We architected Snow Leopard to allow the whole system to run in 64-bit mode on a 64-bit chip, not partial. (Ed. Note: But the vast majority of Macs will still run the OS kernel in 32-bit mode.)

Application developers can package up applications to put both 32- and 64-bit binary in one package. We never wanted the consumer to have to decide, and app manufacturers do not have to offer two versions.

LU: Mr. Paulus, your rebuttal?

Jay Paulus: We do have two versions. When you buy media, it comes with both in the box. We recommend people with 3GB or more of memory install the 64-bit version. (Ed. Note: You cannot upgrade from a 32-bit version of Vista to a 64 bit version of Windows 7. You must do a clean install.)

I think the transition to 64-bit is hard. It takes work to transition to 64-bit. Apple knows 64-bit is hard. They wanted to take credit for the work they did. OS X 10 Snow Leopard doesn't boot into 64-bit by default. And switching between 32-bit and 64-bit causes a big performance hit. The only SKU that boots into 64-bit by default is OS X server. Tough position for them to take, as much as I like their 64-bit logo.

We've had 64-bit and drivers since 2003 on Windows XP. Pretty hard for them to claim a lead on that.

What about Microsoft's two-version approach, as opposed to one binary?I think it's representative, a pretty good way to make transition. As the hardware and software catches up and people have more and more memory in the systems, 64-bit makes more sense. The fact that they can make a choice, is that a bad thing?

Programming for Multicore

LU: Modern computers now feature multicore CPUs. However, consumers aren't always sure if their operating systems or apps are taking fullor anyadvantage of all those cores. What are you guys doing in the multicore space?

BC: We took a step back and rethought the problem. It's a big deal for developers to get the most out of multicore systems. Programmers usually have to write apps differently if there are two, four, or eight cores. Grand Central lets the operating system figure it out. We'll shield the developers from having to worry about it. It's a big breakthrough in software. For application developers to take advantage of it, they only need to add a couple of constructs to their code. It's minimally invasive to the current set of code.

The primary benefit is speed (how fast it goes on screen) and responsiveness, if I click on something on the screen how quickly it comes back.

JP: It's a tough computing problem, the multicore, multithreading, programming across GPU and CPU. These are tough problems, no doubt. Anyone who does this wants to take credit. I feel like Apple is playing catch-up in this realm. We've had threads and fiber since 2000. The Windows 7 kernel is the same kernel as Window Server 2008 [R2]. I would hold our granular scheduling and multicore scaling up to theirs any day of the week. They're providing a queuing mechanism. People will still have to design their apps to be multithreaded. I reject the fact that it's going to fundamentally alter the way people are building apps to be multithreading or multicore.

The Face of It

LU: Okay, let's step out from under the hood and talk about what consumers see on their desktops, specifically, the UI. Mr. Croll?

BC: We have the Dock, Windows 7 has the taskbar. The taskbar took its inspiration from the Dock, but there's a big difference. We handle applications as well as files and folders. In the Windows taskbar, you have to pin the file inside the application. Then you have to go in, click on the Jump List. Not as easy or accessible. We have Stacks that let you put a whole folder in the taskbar. The icons are bigger on the Dock. It scales nicely if you have a lot of items. Expose is there to help you sift through a cluttered desktop. We take full advantage of the entire screen. Click and hold on dock tile, you get a full-screen preview.

With Windows 7, you mouse over an app, you get a series of small thumbnails, you also see a full-screen visualization. It's confusing. There are window panes left over that leave a lot of clutter. We offer graphical previews of the contents of the system. In the Finder, there's Cover Flow, which is just like flipping through album art in iTunes. Windows 7 doesn't have anything like that. We built previews everywhere. Microsoft Windows isn't like that. You have to have apps in OS to preview. In OS X, you can preview without apps.

JP: What did Dock's Expose take inspiration from? (Ed. Note: The implication is that the dock came way after the Windows taskbar.) I think the Windows 7 taskbar, to a Windows user, feels pretty natural, a natural evolution of the taskbar and Quick Launch. I think of Apple's Dock as a launcher, not a window manager. Some of the little things don't get much credit, like Aero Snap and Shake, which help you organize your desktop. Our taskbar is good at managing windows.

In Windows 7, you can hover over Windows and use all instances and overlays with actual controls. You get high-level interaction with applications. I think reviews have been pretty positive overall. You know you really hit the feature on the head when people say, "Oh, I thought it always did that." We've had millions of people testing Windows 7, gotten a lot of feedback, and received lots of positive reviews. Ultimately, UI stuff is tough. It's something everyone gets to have an opinion on.

Backing Up

LU: Okay, let's talk about backupsomething everybody needs, but no one really does. Windows Backup has been around for a long time, but isn't widely used. Apple's Time Machine arrived with Leopard and deep integration with the hardware. Where are we now with OS-based backup?

BC: Time Machine versus Windows Backup: We built it in with Time Machine. It's easy to use, easy to restore, easy to understand, easy to search. There's a huge qualitative difference between what you get on a Mac and what you get on Windows.

JP: There's been some work done to make Windows Backup easier to use. It does a good job of full-system backup. If you have pictures scattered around the disk, you can send them to Library viewBackup is smart about picking up files from wherever they are. Another feature that is key is Previous Versions. It was called Time Warp and we have had it since Server 2003. It manages previous versions of files and is running by default on diskit's a file system feature. There's no separate disk. It doesn't protect you from disk failure, but lets you go back in time to previous versions of files.

Upgrade Paths

LU: Perhaps one of the most stressful things users face is the act of upgrading their OS. With Windows 7 coming out, people will be making choices and possibly upgrading their OS. Mr. Croll, what's Apple's perspective on what's happening with Windows 7?

BC: Over 60 percent of the people are out there running Windows XP. I will point out that Microsoft more or less left the XP users behind. So I'm not understanding the logic.

LU: Mr. Paulus, Brian has a point. There were a lot of netbooks sold over the last 12 to 18 months, and the vast majority of them shipped with Windows XP.

JP: The majority of people get their new OS with a new machine, so the notion that we're leaving behind a vast set of people, I'm not sure I accept that. The fact is that Windows XP shipped eight years ago and hardware and software has moved on. We made a tough choice and I hope in the end that it's the right choice. It's a bit disingenuous for Apple guys to talk about us leaving people behind. On positive side, Windows 7 will run really well on those netbooks.

Windows users aren't left behind to the degree that people who are running those old Macs are being left behind. If you didn't buy a Mac since the Intel transition three years ago, you are really getting left behind.

What's Inside

LU: After years of integrating utilities and even full-blown apps from competing products in the operating system, or as part of the OS package, Microsoft made an about face this year and is letting end users decide whether or not they want to download Mail, Messenger, Movie Maker and other apps. Why?

JP: Pulling things out allows us to update them on a more regular basis. There's more customer value, the apps are more directly integrated with the cloud offerings. I think that people will realize that that's the way they want it: software plus service. Those upgrades are free. Apple can say they include it in the OS, but they also charge you for the upgrade.

LU: Mr. Croll, how do you view the debundling of applications?

BC: We build everything in and put together a package that works beautifully out of box. Microsoft is going in a different direction, pulling out Mail, and other apps and having people download them. For example, we have Exchange support in Snow Leopard. You have to buy Microsoft Office to get Exchange support in Windows 7. We bundle that right out of box.

JP: The premier client for Exchange is Outlook. If you want the full-fidelity experience, you want Outlook. For those that don't want to buy Outlook, there's Outlook Web Exchange. It's a strong, high-fidelity client.

What's Different

LU: In the race to build the best operating system, where do each of you think you stand? What sets you apart? Mr. Croll?

BC: Mac OS X is much simpler than Windows. We're more advanced from a technological standpoint. Windows 7 still has DLL and the Registry, still has defragmenting, still needs activation. We don't make users enter in activation codes.

LU: It's a fair point, Mr. Paulus. Microsoft has done many things to Windows 7, but couldn't change some of the fundamentals like the DLL and Registry.

JP: So what? Yeah, we've got the Registry and DLL, so what? It's not something we talk about. We do a lot of work around reliability and performance. Getting into notions of replacing Registry and DLL, it just doesn't become relevant.

LU: What about Mr. Croll's activation and technology comments?

JP: Apple has a different model. They charge you a lot of money for the hardware and charge you again for the OS. We're selling you the OS. We use the activation to help ensure that you have genuine versions of Windows out there.

Pricing

LU: Let's talk about pricing. There are free operating systems out there, like Linux, but, as we can see from market share, free does not necessarily translate into mass-market adoption. How do the two of you see price and the OS?

BC: With Snow Leopard, the upgrade price is $29 for Leopard users or $49 for a family pack with five licenses. With Windows 7 Ultimate, the upgrade is $119 for Home Premium and $199 for Professionalthat is really expensive software.

LU: Jay, I know Microsoft has one $30 plan for students. What else do you have to say about pricing?

JP: Snow Leopard is much more akin to a service pack and Apple is charging $29. We don't do that. Windows 7 demonstrates a lot of customer value and priced at a pretty attractive price point. Most users get their OS automatically when they buy a new system. With Apple, you're going to be paying an Apple Tax. You're going to have to buy their expensive hardware just to get in the game.

Making the Choice

LU: Okay, here's your opportunity to make your case for your OS. Mr. Paulus, why Windows?

JP: I would say it's all about value, choice, compatibility, and simplicity. Value we've talked about that lot. There is value in a Windows ecosystem with nearly a billion users and thousands of PCs manufactured. Having lots of apps and systems drives a lot of end-user value. Stack any PC up against a Mac, we'll win pretty comfortably.

Windows 7 was designed around simplicity. It offers innovative features that set it apart, including Jump Lists and . A whole bunch of things that we think will make Windows 7 land as a game changer. I think the game has changed.

LU: Mr. Croll? Why should people choose Snow Leopard?

BC: Over last ten years we've been adding a lot of features, and it all culminated with Leopard. It's the best-selling software product Apple has ever done. It added things like Cover Flow and Time Machine. For Snow Leopardthe goal was to make a better Leopard. Mac OS 10 was made up of 1,000 different projects. For Snow leopard we refined 90 percent of them. Mac OS 10 continues to be much simpler than Windows.