I've written a lot about Windows XP Service Pack 2 (SP2) already this year, but XP SP2 will be a hugely important Windows release, arguably as important for businesses as XP itself. During the past few months, I've been using XP SP2 on a variety of machines to see how its security-oriented updates affect the functionality of the OS and third-party applications. So far, so good: With one exception (a Netgear networking print server that refuses to respond to XP SP2 clients), all my applications and hardware have worked just fine with XP SP2.

Tablet PC users, however, will be particularly impressed with the upgrade. In addition to all the bug fixes and security enhancements that any XP user can expect from XP SP2, Tablet PC users will see their OS upgraded to a new version of the Tablet PC OS, dubbed Windows XP Tablet PC Edition 2004. Code-named Lonestar, this version of the Tablet PC OS is dramatically enhanced over the initial version, which was one of the more mature Windows releases I've evaluated.

Microsoft originally planned to deliver XP Tablet PC Edition 2004 separately from XP SP2, as it had done with Windows Media Center Edition (MCE) 2004 (code-named Harmony), the update it shipped for Media Center PCs late last year. But with the XP SP2 security push, Microsoft realized that it would better serve customers by tying these releases together. So the company asked PC makers to pull their Harmony upgrade offers and integrated both XP MCE 2004 and XP Tablet PC Edition 2004 into XP SP2. XP SP2 will apply to all XP users, but Media Center PC and Tablet PC owners will experience other significant enhancements that are unique to their systems.

I won't tarry long with Media Center here, but if you're curious about the enhancements in XP MCE 2004, please check out my review on the SuperSite for Windows ( http://www.winsupersite.com/reviews/windowsxp_mce2004.asp ). XP Tablet PC Edition 2004, meanwhile, arrives with some major improvements.

In the original XP Tablet PC Edition, Microsoft included an Input Panel window, which is typically docked to the bottom of the screen. This panel lets a pen-toting user enter text in text boxes and other interfaces in applications that aren't specifically designed to work with a Tablet PC. The Input Panel is a nice feature--and it lets Microsoft tout that Tablet PCs are supersets of traditional notebooks--but using the tool is a bit ponderous. Consider the steps you need to complete to fill out a simple Web form: Select the first form field with the stylus, click in the Input Panel, and write the value you wish to enter. If the handwriting-recognition software transcribes your writing to text correctly, click the next field; otherwise, highlight the entry and correct it. Repeat the process for each form field.

XP Tablet PC Edition 2004 offers an easier data entry method. Although an improved Input Panel is still available at the bottom of the screen, the OS now sports in-place form-field editing: Click a form field with the stylus and a small version of the Input Panel appears right there--no need to move between the form elements and the bottom of the screen. This in-place editing feature is handy, but the Input Panel has been further improved. Now, as you enter text, you can edit it on the fly, ensuring that the text you enter in the form is correct the first time. Nice.

For developers, XP Tablet PC Edition 2004 offers improved capabilities as well. Using a new software development kit (SDK) tool, developers can add form-field context-sensitivity capabilities to their applications without needing to recompile them. Instead, the tool creates a simple XML file that developers can copy to the installation folder for their applications). Here's how it works: If you create a form field that can contain only certain values (e.g., state names, numbers), you can now constrain the Tablet PC recognition engine, making the results more accurate. In other words, if the Tablet PC OS knows that a field can contain only numbers, it will try to match the user's chicken scratches against only numbers--not against the entire set of possible characters a user might enter.

You might question whether Microsoft's grand experiment with handwriting recognition and Tablet PCs has borne much fruit. After all, as 2003 wound to a close, PC makers were bemoaning slow sales. Microsoft is optimistic, however. With key vertical markets such as health care, sales, manufacturing, and education offering a wide range of Tablet PC-specific solutions, it appears that the Tablet PC has established a viable niche. But the company envisions its Tablet PC software eventually running on all notebook computers, and PC makers have responded to that vision by unleashing a wide range of Tablet PC hardware types that dramatically dwarfs the options we saw last year.

The original Tablet PC devices were hampered primarily by weak Pentium III processors and poor battery life, but 2004 versions are benefiting from the emergence of powerful and power-thrifty Pentium M processors. PC makers, meanwhile, are shipping Tablet PCs in various sizes and shapes, with some companies--notably Gateway--even offering Tablet PC versions of existing notebooks for just a small premium. These machines, I suspect, point to the future of the Tablet PC and suggest that mainstream success is inevitable. I'm hoping to review some recent Tablet PC designs soon, however, to test that hypothesis.

XP Tablet PC Edition 2004 will ship by June 2004 as part of XP SP2. It will be a free upgrade for existing Tablet PC customers and will be available for download from the Microsoft Web site.

More Mobile Thoughts
An IBM representative wanted me to pass along a crucial bit of information: Although the cramped quarters on the IBM ThinkPad X40 I reviewed last week were a bit small for my oven-mitt-sized hands, the keyboard wasn't the reason: The X40's keyboard is the same one used in the company's slightly larger ThinkPad X30 series. I suspect the discomfort I experienced related to the smaller wrist rest, but I can't be sure because I don't have an X30 series handy to compare. In any event, the X40 will likely work just fine for most regularly proportioned adults, and the machine's battery life is quite simply the best I've seen.