After lots of whispers, rumours from beta testers and confusing messages from Microsoft executives, Microsoft has finally revealed the full details about Windows Vista's first service pack. The company confirmed a three-month launch window, with a beta testers getting their hands on the update during September.

There are unanswered questions, but we know more now than at any time since Vista’s launch and there’s a lot riding on the success of the upgrade.

With that in mind, we took our first shot at SP1. Certainly, there will be more.

In the meantime, all hail SP1.

When will Windows Vista SP1 roll out in beta, and when in final form?

Microsoft is saying only "a few weeks" and "September", which are, after all, one and the same, for the beta. As for the final release, the software maker finally acknowledged rumours circulating June that the service pack be fully available until the first quarter of 2008. Earlier talk had centred on the last quarter of 2007 as the presumed ship time for SP1, but that's clearly not in the cards. Microsoft’s August briefing included a slide with the line "Release date will depend on confirmation from beta testers," which is essentially what the company said numerous times in 2006 as it worked toward Vista's delayed launch. In other words: Microsoft is leaving itself room for manoeuvre.

Who will get a crack at SP1 beta?

You might want to sit down. Microsoft has said that it will seed the September build to between just 10,000 and 15,000 partners and customers. Don't act so surprised - the beta track regularly runs from private-private to private-public to public-public, with few deviations and no detours. How it plans on doing that is a mystery. Invite only? Concert seating, mad rush to the URL? Lottery?

Microsoft has confused us with its nomenclature. On the Vista team's blog, program manager Nick White said, "A later pre-release of SP1 will be available to a larger group of testers via MSDN and TechNet subscribers." Later prerelease? Does that mean the beta, or a post-beta, such as the inevitable release candidate? We're awaiting clarification.

Will there be a bigger beta, a public-public?

Yeah sure, why not? Actually, Microsoft said it would distribute the beta, or maybe a release candidate, to a larger group between September and the final release. Details? Nothing more than White's confusing comment. You decipher; they'll decide.

Why all the fuss about a service pack, anyway? We have a couple of explanations as to why Service Packs are now very important to the Windows food chain. First, the obvious. The advice to wait for the service pack may be apocryphal, but if it is myth, it has become reality. Microsoft needs to stake out SP1 to convince major customers that it's time to deploy its not-quite-so-new operating system. Sure, they've already paid, or most of them have, for Vista with licensing agreements such as Software Assurance. But the sooner they move to Vista, the sooner they will, presumably, move on to what comes after Vista.

Second, and this is often overlooked, is that the last Windows client service pack - 2004's XP SP2 - set the bar very high so high that expectations of what a service pack is have grown all out of proportion to what Microsoft will deliver. XP SP2 wasn't just a service pack. As defined until then, an Service Pack was little more than a collection of bug fixes and security patches, tested more thoroughly in the aggregate, but still a collection. XP SP2 changed that by making sweeping changes, most of them in the security arena, to the operating system. Remember, SP2 was the first service pack to be delivered by Windows Update - not only delivered, but force-fed to users. Because of XP SP2, there's much more made of Vista SP1 than if that 2004 update hadn't happened.

From Microsoft's description of Vista SP1, users expecting another XP SP2 will be disappointed. This is much more in the historical tradition of service packs. For that reason, expect to hear some SP1 backlash or pooh-poohing by users, analysts, bloggers and yes, maybe even a reporter or two.

How big is SP1?

At the moment, according to Microsoft, it's around 50MB in the form that will be squeezed through Windows Update and Windows Server Update Services (WSUS). The actual size of the update is likely in the 684MB range of the build leaked last week to BitTorrent Inc. Microsoft managed to reduce the download by both compression and delivering only the file each specific PC needs. In comparison, Windows XP SP2 weighed in at 266MB.

The standalone service pack designed for businesses that want a way to update multiple machines is considerably larger: 1GB or so on the DVD. This is what enterprises using System Center Configuration Manager 2007 will deploy.

More to the point of size - except to those who still live and die by dial-up, to whom 50GB might as well be 50TB - is that installing SP1 requires what Microsoft characterises as "a large amount" of free space on the drive. How large? Try 7GB for 32bit, around 12GB for 64bit.

What's Microsoft removing from Vista with SP1?

This may be a first, but the service pack is actually subtracting from Vista, not just adding. According to the white paper Microsoft released this week: "The service pack will uninstall the Group Policy Management Console."

GPMC, which debuted with Windows Server 2003, is a one-stop console for setting operating system policies that, say, ban everyone in the office from downloading potentially poisonous .exe files. Instead, the older GPEdit.msc application will have to suffice, at least for a while. "In the SP1 timeframe," it said, "administrators can download an out-of-band release that will give them the ability to add comments to group policy objects (GPO) or individual settings and search for specific settings."

The 'out-of-band release' in that sentence refers to an enhanced version of GPMC, which will presumably be issued before, at the same time, or after SP1.

Why? Microsoft isn't saying much, except that "administrators requested features in Group Policy that simplify policy management".

Vista, who cares? What's the deal with the next service pack for Windows XP?

Glad you asked. Microsoft, which has been avoiding the topic of XP SP3 even more judiciously than Vista SP1, confirmed that it will dual release the last rollup of the I'm-not-dead-yet XP "in a few weeks" or "in September". And it hasn't changed the long-stated, long-in-the-tooth schedule of sometime during the first six months of 2008 for a final release.

Here's the situation on XP SP3. "It is a standard practice to release a service pack as a release nears end-of-life for the convenience to our customers and partners," said Microsoft. "Windows XP SP3 is rollup of previously released updates for Windows XP including security updates, out-of-band releases and hot fixes. It will also contain a small number of new updates. This should not significantly change the Windows XP experience."

Smell like an obituary to you? It's almost as if Microsoft's embarrassed by how well XP's hanging in there. In fact, we don't believe for a minute that Microsoft, which has previously set a drop-dead date of January 30, 2008, for manufacturers to preinstall XP on new PCs - and January 30, 2009 as the similar deadline for smaller-scale system builders - will actually follow through on those deadlines, what with SP3 coming down the pike sometime between the two. Microsoft will likely smell the XP coffee, and extend at least the manufacturer deadline.

Back to Vista. What's in SP1?

Microsoft breaks down the contents into three categories:

- Reliability and performance updates
- Administrative improvements
- Newfound support for some of the newer standards

It'll also include all the updates, patches and non-patches that have been released between Vista going RTM (release to manufacturing) late last year and now, or whatever as-yet-unknown cut-off date Microsoft plans to establish. Several security-related changes that don't easily fit into any of the above categories will be in there, too.

Tell me more.

The company white paper lists what Microsoft claims will be in SP1, but there aren't many surprises in the reliability and performance section. Vista will play better with more graphics cards, work better with more printers - two major hardware clans with which Vista has been notoriously flaky - come out of and drop into sleep and/or hibernation more reliably (ditto), run Internet Explorer without chewing up as many CPU cycles, and copy files faster.

The BitLocker drive encryption tool within some Vista offerings - Ultimate and Enterprise only - has been updated so it can encrypt any local drive, not just the primary, or c:, drive. And the Network Diagnostics tool has been enhanced, says Microsoft.

On the new support side, SP1 adds support for the exFAT (Extended File Allocation Table) file system, which is used on flash-based storage devices, typically on Microsoft CE-based devices. The 64bit version of Vista SP1 also adds Extensible Firmware Interface support, letting 64bit PCs network boot with this BIOS replacement. 'Network boot', by the way, refers to cranking up a PC remotely and often applies to diskless clients that run their operating system and applications off the network.

Got anything else? How about something juicy?

This is the best we can do for you: SP1 will include the changes to Vista that Microsoft has agreed to after being pressured by the European Union's antitrust watchdog and then the US Department of Justice.

To get the EU's Competition Commission and its chief, Neelie Kroes, off its back last year, Microsoft bowed to criticism from the likes of Symantec and McAfee and promised to produce several application programming interfaces (API) that would give security vendors some access to the kernel of 64bit Vista, Microsoft's PatchGuard protection schemes notwithstanding. Also in SP1: another API that allows security companies to better integrate their products’ on-screen status features with Vista's built-in Windows Security Center.

This year, Microsoft did a similar dance with Justice and the states involved in the 2002 antitrust settlement over Google's complaints about search in Vista. Microsoft agreed to a number of changes in Vista, including one that lets user disable Vista's built-in search engine and switch to an alternate, such as Google Desktop.

Where can I get more information than what you've deigned to drop on me?

Your best bet - other to check back here - is the official white paper from Microsoft. (Note: A PDF of this will probably be stuck somewhere on the Microsoft site in the new future.)