Comparing the Sony U750 with the HP tc1100
I have been talking about a mini-tablet for quite some time and the notion of a small tablet stoked a lot of people’s imaginations when Bill Gates demonstrated the Haiku mockup at WinHEC earlier this year. A lot of the discussion I have seen since this demo has centered around two distinct areas- are there usability issues with a very small Tablet and how well does the Tablet Edition of Windows XP run on a passive digitizer (touchscreen). There have also been hints dropped by Microsoft that future Tablet devices might have either a touchscreen or both an active and passive digitizer so it is important to analyze usability issues on a touchscreen. I am in a unique position to take a look at both of those areas since I used a Sony U750 with the Tablet Edition installed for quite some time. I used the Sony full time for months and have a very good perspective about the usability limitations of the small form factor. I have been asked by many people how I would compare the Sony U Tablet experience with that of the HP tc1100 Tablet PC I now use. This article is intended to hopefully answer some of those questions.
Comparison of the two interfaces
The hardware interface of the Sony U750 is very carefully designed to allow full operation of the ultra-portable computer (UPC) without the use of a stylus. On the front of the Sony is a joypad that works as well as any Track stick I have used on a notebook computer. This joypad is located on the upper right of the front of the Sony (sorry lefties) and placed just below it is a scroll pad. The scroll pad allows movement in four directions and is nice for scrolling through documents and web pages in the browser. The scroll pad has a central button that sends an ENTER key when pressed. On the left of the Sony are three mouse buttons that work just as you would expect and they allow full control of the interface in combination with the joypad. You can completely run the interface with these buttons and never pick up a stylus if that’s what you want to do. Other buttons on the front of the Sony include a video zoom button for changing the resolution on the fly, including resolutions that are bigger than the physical screen which result in a panning desktop.
The screen of the Sony U750 is a 5" screen running at 800×600 and it incorporates a touchscreen that requires physical contact to register a response. The UPC can be used in either landscape or portrait orientation, and when rotated either way all of the hardware buttons rotate accordingly which makes for a smooth transition. The passive digitizer of the Sony runs at a lower resolution than the active digitizers in Tablet PCs like the one in the HP, and this can sometimes result in "jagged" ink when writing on the screen, especially in portrait. I noticed no ill effects from this lower resolution when comparing it to an active digitizer.
The hardware interface of the HP tc1100 is very different from that of the Sony, as there are no mouse buttons or joypad. This means that the pen is required to manipulate the interface, which is not always convenient when you just need to check some information on the fly. You have to grab the pen and work the screen to do that. The HP does have some hardware buttons including an ESC, TAB, and Ctrl-Alt-Del button for resetting when needed. A very welcome inclusion on the HP is the rocker button which operates as a scroll up/ down and ENTER key when pressed in the middle. The larger size of the HP screen may preclude the benefits of having some sort of joypad as it might be difficult to cover the larger screen real estate with a trackstick, so it is likely no big loss. I do think that any device with a screen smaller than this does need some sort of joypad for pen-less interaction, however.
The screen of the HP tc1100 is 10.4" running at 1024×768 and has the active digitizer that all Tablet PCs have. The active digitizer is part of the Microsoft specifications that are necessary for OEMs to produce Tablet PCs and is the main reason the Sony U750 will never be released as a true Tablet PC in its current form.
The Tablet Edition implementation on the Sony
When I first received the Sony a year ago I immediately installed Windows XP Tablet Edition which is available to those with an MSDN subscription. In fact I have to admit that I intended to install the Tablet Edition even before obtaining the Sony and it is the main reason I got one. When I first installed the OS I wasn’t sure how much of the functionality would be missing on the Sony since the screen is so small and is not an active digitizer. I really thought there would be significant compromises for these reasons but my experience in actual usage was quite different. The lack of an active digitizer means there is no hovering of the cursor as you have on real Tablets. The touchscreen only registers cursor movement when you touch the screen so any functions that require a hover ability are not possible. In practice, I only found one area where the lack of a hover made a difference. On real Tablet PCs when you hover the cursor in a text entry area in most applications you get the "floating TIP" icon when you tap to open up the Text Input Panel (TIP). This is the area you enter all text via handwriting so this is a big deal, but an enterprising Sony user wrote a utility to duplicate the functionality on the touchscreen. This shows how easy this would be to do on touchscreen Tablet PCs and with this utility it functions identically to a real Tablet floating TIP.
The Sony running with the Tablet Edition provides the same handwriting recognition (HWR) that is integral to this OS. I found the HWR on the Sony to be just as accurate as that on the HP or any other real Tablet PC. This is interesting since the touchscreen is a lower resolution than the active digitizers used in all Tablets so I expected a loss of accuracy in the HWR, but I did not find this to be the case. I have seen others claim that the HWR on the Sony is not as accurate but in my experience this is not the case at all. I can safely say that my accuracy over time on the Sony was just as good as it is on the HP. For this reason I am convinced that touchscreen Tablet PCs will work just as well as active digitizers for typical office work. Note that the touchscreen on the Sony is not pressure sensitive like the active digitizers so programs that depend on that sensitivity, such as drawing type programs, will not work as well.
Comparing usage of the two devices
The two devices are different enough that comparing them is not easy. The first thing you notice is working with the interface. The Sony makes it easy to whip out and check something quickly, partly due to its small size and partly due to the hardware buttons I’ve mentioned. The HP is harder to use quickly as it is much bigger and you have to use the pen to interact with the OS. With more extended sessions the differences even out a lot, as the larger screen of the HP makes working on documents much easier than the little Sony screen, which means less scrolling. Handwriting on the screen is very similar on both machines with one notable exception. The small screen of the Sony makes entering longer pieces of text more cumbersome than on the HP. The Sony screen is physically a little smaller than an index card, so imagine entering all your text on index cards. You can only fit a few words on each line in landscape orientation, and even fewer in portrait. This has a tendency to break the flow of handwriting on the screen as you must roll over to the next line every four or five words. I also find my hand gets fatigued very quickly working on such a narrow screen which makes long passages tiring to do on such a small screen.
Since the accuracy of the HWR is good on either device there is no notable difference in the inking experience. The main difference in this area lies in the manipulation of the TIP, as the TIP and on-screen keyboard are very small on the Sony. One thing that is apparent is that to enter ink on any device with a screen smaller than the HP you really need write anywhere ability. That’s where you can handwrite text anywhere on the screen and not within the physical constraints that are imposed by using the Tablet TIP. This makes it more efficient to enter longer passages and is just plain easier to do. It is not an issue on the HP but crucial to successful use of the Sony, and I think any small screen Tablet will need this ability.
Touchscreen vs. Active digitizer
The thought of putting a touchscreen on a Tablet PC sends TPC purists running screaming from the room. The standard party line is that touchscreens are just not accurate enough to provide accurate handwriting recognition but I can tell you that my experience shows this is not the case. The only real issue with a touchscreen Tablet is due to the fact you cannot rest your hand on the screen while writing, as you can with active digitizers. Touchscreens register hand contact as if it is a stylus meeting the screen and this is why larger Tablets have active digitizers. In practice, the very small Sony screen makes it possible to ink on the screen without needing to rest your hand on it but once you make the screen even a little bigger you will have problems. That issue aside, the experience of interacting with the two screen types is virtually identical. This really surprised me but that’s the way it is. It shows that touchscreens can be used in Tablets without negative affect, as long as the screen size is small enough that you can write on it without touching it with the hand.
What’s it all mean?
So what conclusions can we reach based on my experiences with the two different devices? One thing is clear, if anyone makes a small Tablet PC like the Haiku prototype it could have either a touchscreen or an active digitizer without compromises. But, it is my opinion that for such a small device to be useful it needs some sort of hardware interface like that on the Sony U750. A pen-only small device will lose a lot of utility without them. For my money I would also like to see Haiku with a larger screen, maybe 8 inches, as it is just too hard to write lots of text on screens smaller than that size. It is also physically uncomfortable for extended use as I mentioned. I don’t see the point of producing a limited function Tablet no matter what size- we already have capable PDAs. I would rather see a complete Tablet PC with a screen large enough to be used for virtually everything you might use a larger Tablet PC.
If the issue of hand contact on the screen can be resolved then a touchscreen can provide a good Tablet experience. There are touchscreens in existence that only react to contact with a pen so this may not even be an issue for future small Tablets. Passive digitizers are cheaper to produce and use less power and would be right at home on small Tablet PCs. Maybe we will see a mini-Tablet some time next year which would be very cool. It would likely attract consumers to the Tablet form who otherwise would not consider one, and that’s a good thing.