This alternative Kindle, called the DX, is a super-size version of the popular Kindle 2, which arrived earlier this year. It sports a 9.7-inch screen, some 2.5 times as big as the surface area of the Kindle 2’s 6-inch display. It also sports a higher price tag — $489, versus $359 for its smaller sibling, which remains on the market.

Amazon’s Kindle DX

Like previous models, the Kindle DX allows you to shop for, and wirelessly download, any e-book in Amazon’s (AMZN) growing catalog — now about 275,000 titles. It uses the same easy-on-the-eyes screen technology as the smaller model but at a higher resolution. It still lacks color, and renders images only in gray scale. But the new DX adds a new capability: auto-rotation, which allows you to read in landscape mode.

This new, larger model isn’t primarily aimed at readers of standard books. It is targeted at three markets: textbooks, newspapers and other periodicals, and business documents in either Microsoft’s (MSFT) Word format or Adobe’s (ADBE) PDF format.

Unfortunately, I’ve been testing the Kindle DX and I didn’t like it nearly as much as the Kindle 2, which I own and enjoy using daily. While it performs its promised tasks adequately, I found that its size and weight made it awkward and tiring to hold for long periods of reading. It’s still fairly thin and light, but it’s 85% larger and heavier than the standard Kindle.

In addition, Amazon has degraded the user interface. To prevent the device from being even larger, the company had to remove the left-side page-turning buttons, confining all the controls to a vertical strip on the right. The keyboard at the bottom is also more vertically cramped.

If you’re left-handed, you have to spin the device around and rotate the screen to get buttons on the left, where they appear with their labels upside-down.

Similarly, if you choose to read in landscape mode, all the navigation controls, including the joystick for moving the cursor, will be awkwardly placed at either the top or bottom, far from where your hands are holding the device, and the keyboard essentially will be unusable.

In my view, the Kindle DX would have been a better product with on-screen touch controls that could instantly adapt to its size and orientation.

In reading standard books on the DX, I also encountered instances where the text on a page varied in shade from light gray to black.

I had mixed results with business documents. As with previous Kindles, you can either email personal documents to your device, for a fee, or drag them onto the Kindle via a cable, for free. But, unlike the smaller models, the new DX has PDF display capability built in, so it renders PDF files much more accurately than the older Kindles. That is a big improvement. It also allows you to view Excel and PowerPoint files if you save them in PDF format before sending them to your Kindle DX.

The Kindle DX, right, is a large-screen version of the popular Kindle e-reader, left.

I tried a variety of documents, and in many cases the results were great. The text was crisp, and the tables and graphics looked like they should. But I found that on some of these PDF documents, the text was too small to read. Yet, the Kindle lacks the ability to zoom in on PDF documents. You often can make the type larger by rotating to landscape mode, but this splits the PDFs into multiple pages, sometimes breaking them awkwardly.

Also, Amazon has raised its fees for converting and delivering business documents via email to all Kindles. The charge was formerly 10 cents a document. Now, it’s 15 cents per megabyte, which can add up if you load up your Kindle with lots of large documents. Most of my test documents, which were fairly small, cost over $1 each.

Newspapers looked about the same on the DX as they do on the smaller Kindles. Despite the larger screen, they don’t use traditional print or Web layouts, but a special Kindle layout that some users like a lot, but which I find annoying because it makes it harder to quickly scan multiple headlines.

The Kindle DX does have some nice touches. For the extra money, you not only get a larger screen, but also about twice the storage capacity. Also, because the screen is wider, you can adjust the margins on the DX, to obtain a line length that’s comfortable for your eyes and optimal for reading speed.

Amazon claims the same multiday battery life for the DX as for the Kindle 2. In my tests, I was able to go for several days of moderate reading without recharging, and much more if I turned off the wireless capability.

Although I wasn’t able to test college textbooks, I suspect they may be the killer app for this product. Many already are so expensive and heavy they could make the weight and price of the Kindle DX seem trivial in comparison.

But for standard books, I’d stick with the smaller, more comfortable Kindle 2.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.

Linux on netbooks isn’t going away though. In fact, software and hardware companies have been making big investments to improve Linux netbooks. For the past week, I’ve been using several flavors of Linux running on netbooks — Ubuntu, Hewlett-Packard’s Mi (which is based on Ubuntu) and Moblin, created largely by Intel and not yet available commercially. In all cases, the Linux netbooks failed at some basic functions that any laptop, no matter how tiny and inexpensive, should be able to handle, like working with printers. At the same time, Mi and Moblin have impressive graphical user interfaces well-suited to the habits of typical netbook users, like checking email and accessing social-networking sites, as well as the small screens and low horsepower of tiny laptops. In addition to Linux, all of the computers shared the standard features, or lack thereof, common among netbooks, including compact keyboards and no DVD drives.

H-P’s Mini 110 Mi Edition

The most polished of the products was H-P’s Mini 110 Mi Edition, a new model with a 10.1-inch screen that H-P will begin selling on its Web site for $279.99 on June 10. That’s nearly $50 less than what H-P will charge for the Mini 110 running Windows XP, which will come with a 160-gigabyte hard drive instead of the 8-gigabyte solid-state drive that will come with the Mi edition.

The striking thing about this netbook is the slick graphical user interface created by H-P that runs on top of Ubuntu and first began appearing on H-P netbooks early this year. Instead of a traditional desktop like that found in Windows and the Mac, Mi (pronounced “me”) arranges commonly used applications and content on a screen called the “dashboard,” which looks like a personalized Web page and lists recently received emails, fresh thumbnail images of favorite Web sites, and a Web-search toolbar.

The Mi home screen is a clever way to make the computer seem alive with on- and off-line content, which is fitting since netbooks are designed for on-the-go Internet activities. It’s also tailor-made for the small screen size of netbooks.

A more eye-catching iteration of Linux is Moblin, which I tried out in test form on an Acer netbook; it is expected to ship on netbooks by the end of the year. Moblin has a menu of icons at the top of the screen, the most interesting of which leads to the M-Zone, a home screen that displays calendar appointments and favorite applications alongside snapshots of recently visited sites and a continuous feed from the user’s Twitter network.

An icon called “People” leads to a list of instant-messaging buddies, while another, called “Zones,” let me organize all the applications I had launched into different virtual workspaces, which is useful for hopping between various tasks on a small-screen device like a netbook.

The look and feel of the standard Ubuntu system, without the Mi interface, is more commonplace. I tried out a Dell Mini 10 with a 10.1-inch display and 160-gigabyte hard drive that sells for $349 on Dell’s Web site. The Mini 10 ships with version 8.04 of Ubuntu, which resembles Windows XP, with its desktop, taskbar and pop-up menu system. Ubuntu, in some cases, seemed to overestimate the size of the Dell Mini’s display: A window for configuring wireless-networking capabilities was so large it bled off the screen, and I couldn’t access all the buttons on it. I also installed on the Dell a new version of Ubuntu Netbook Remix, which works better on small screens. Since a Windows XP version of the Dell Mini 10 sells for the same price as the Ubuntu, I can’t see a compelling reason to choose the Ubuntu option.

All the netbooks I tried had compatibility problems with other external devices. The netbooks couldn’t load the software drivers to let me print to my Canon and Dell printers. I couldn’t load pictures over a USB cable from my Canon PowerShot SD750 digital camera. I was able to get my pictures on the machines by plugging a storage card from my camera directly into the netbooks.

Canonical, the London company that oversees development work on Ubuntu, says it is improving the system’s compatibility with various devices. Intel says it is unfair to judge Moblin until it is commercially available.

Some key applications currently don’t run on Linux, like Apple’s iTunes, which makes it difficult to load music files onto iPods from the netbooks. While the Linux laptops didn’t run Microsoft Office, they came with OpenOffice, a free package of word-processing, spreadsheet and presentation applications that allowed me to open and modify basic Word and Excel files.

The companies behind Linux netbooks have made great strides in improving user interfaces, but until they can achieve similar breakthroughs in how the machines work with other devices, Windows netbooks are still a better deal.

• Email nick.wingfield@wsj.com. Walter S. Mossberg is away and will return next Thursday.

While these location-sharing services have some interesting possibilities, they also raise some disturbing implications for privacy — or maybe it just seems that way if, like me, you’re over 35 years old. Lately I’ve been testing a cellphone location-sharing service that I found simple, useful and non-creepy enough that I can imagine people thirtysomething and older using it.

Send a ‘Glympse’ to share your location

The free service is called Glympse, from a company of the same name that has designed it to share your location with friends and colleagues in small increments of time — glimpses, as the name implies, of your whereabouts. Glympse just released a test version of the service as an application for the G1, a phone offered by T-Mobile that runs Google’s (GOOG) Android operating system.

The company will release versions of Glympse for BlackBerry, Windows Mobile, iPhone and Nokia (NOK) phones in the coming weeks. Users can download the Glympse software onto G1 phones through Android Market, the online clearinghouse for applications for Android phones.

I used Glympse on an iPhone and a G1 and, for comparison, tried out a couple of other location-sharing applications, Google Latitude and Loopt. When you start the Glympse application, it identifies where you are on a map using a combination of location technologies in cellphones, including GPS satellites, Wi-Fi hot spots and phone towers.

Your location isn’t shared with others until you “send a Glympse” to someone. The software allowed me to send a Glympse with my location for selected chunks of time lasting anywhere from zero minutes to four hours. Picking zero minutes shared only my location at the moment of sending, while selecting four hours meant the recipients of my Glympse could track me for that period of time, wherever I went.

The sender of a Glympse can address it by entering a recipient’s email address, or a mobile-phone number for a text message. Recipients get a message with a link to a map on a Web page. A nice thing about the service is that it doesn’t require recipients to have the Glympse software, though the experience is richer when they do.

Sending a Glympse can be helpful anytime a friend, family member or colleague is expecting you. You can send a Glympse that lets a friend know you’re stuck in heavy traffic (although it’s wise to do that before you’re on the road to stay safe and, in some states, to avoid breaking the law). Parents can insist that teens send a Glympse when they go out for the evening.

Bryan Trussel, the CEO of Glympse, sent me several Glympses with short messages like “late lunch meeting” and “headed home” to explain where he was going. On the G1, I could see an icon representing Mr. Trussel moving around a map as he drove through the streets of Redmond, Wash., including his speed. I was also able to see traffic conditions, which would have been helpful if he had been running late. Glympse gave me a similar view of his location through a Web browser running on my PC. On the iPhone, the experience was more static, forcing me to reload a Web page to get a fresh view of Mr. Trussel’s whereabouts. Glympse says it will fix this so users of the iPhone can watch someone’s location in real time.

I encountered a bug with the service when I sent a couple Glympses to my own cellphone and that of a colleague — both BlackBerrys and neither of which had Glympse software. Both Glympses linked to high-level maps suggesting I was somewhere in North America, which wasn’t very helpful, even if it was technically accurate. The company couldn’t figure out what the problem was, and it eventually stopped happening for me too.

Once a Glympse expires, the service no longer tracks the sender’s location. It will show the sender’s last known location for 48 hours after the Glympse expires. Glympse may some day use your location information to target advertising to you, but the company isn’t doing that for now.

I’m far more comfortable with this form of finite location-sharing than the approach used by other services. Google Latitude lets you share your location to only a list of friends. It gives you the option of turning location sharing off or, through a “city level” option, it reveals only your general whereabouts. Loopt similarly allows you to set options to show, or hide your location from all or some online friends. A feature called Loopt Mix lists strangers you can send messages to in your general vicinity — many of whom seemed to be looking for romantic partners in my area.

Despite these controls, I easily forgot I was sharing my location with these two services. This might be fine for someone who enjoys being tracked down by friends during a night out on the town or is diligent about changing privacy settings when they want to go stealth.

I’m too lazy to manage my privacy so closely though. I don’t mind giving friends a look at my location, but only if I know the invitation isn’t open-ended.

• Email nick.wingfield@wsj.com.