Palmtop. The word evokes an image of a pocket-size electronic device that lists phone numbers, addresses, and birthdays. But did you know that a vintage 1995 palmtop -- also known as a "pocket personal computer" or a "personal digital assistant" -- can perform many o f the same functions as a PC laptop? It stores databases, sends and receives E-mail, holds word-processing programs, keeps a detailed schedule with reminders, and sends faxes. And it works for weeks on a small battery, fits in your pocket, turns on instantly, and costs less than ev en the cheapest laptop.

Of the 10 or so outfits that have tried to design the perfect palmtop, some have stayed with the keyboard (Hewlett-Packard is one), while others have ventured into input by pen (Macintosh, for example). Only Sharp Electronics (800-237-4277) has managed to integrate keyboard and pen: users can type in data on a standard QWERTY keyboard or write on the screen with a blunt pen that stores neatly in the unit. Sharp's Zaurus ZR-5000FX ($849) is slightly smaller than five by eight inches, weighs less than a laptop battery, and has a PMCIA Type II slot, a miniature external modem, and the ability to import ASCII text files. On the software side, it has a suite of integrated word-processing and database tools that make handling any personal, and most professional, information easy and efficient.

Fine. But what does it really do? Well, in the first week I had the Zaurus, I did the following: I typed this review on a beach in Hawaii. (I'm six foot three and can palm a basketball, yet I found typing on the tiny Zaurus keyboard easy.) When I was done, I printed the review out on a fax machine in my hotel so I could edit the paper copy. When I arrived at my vacation condo, in North Carolina, I faxed the final copy to Inc. I also checked my CompuServe mail daily, reached across the Pacific (I live in Japan) to check my Internet mailbox, amused my daughters in restaurants by letting them doodle on the Scrapbook, and faxed my wife a hand-drawn map to my brother's house, in Connecticut. All this on two AA batteries.

A feature that distinguishes the Zaurus from other palmtops and PCs: its ability to link handwritten, typed, and graphic data. For example, suppose you've created a folder for a building-design project. In it you file daily reports, phone numbers, contact data, a database of standard engineering specs, handwritten notes taken at the work site, and hand-drawn maps. Later you can transfer the folder to a PC, refer to it as you brief the boss, or fax it anywhere in its entirety.

The downside: The manual is incomprehensible. Add-on electronic cards designed for the Sharp Wizard don't work with the Zaurus. Also, to print a product on the road, you have to send it through a fax machine (though you can print to a laser printer if you're carrying a proprietary cable or an infrared receiver). The Zaurus also unceremoniously dumps any input that is written too quickly in the pen-based notebook. Finally, its communications software is very rudimentary. Still, using the Zaurus, I accessed Compu- Serve from Honolulu, New York, Paris, and Bangkok without any problem.

If you worship true portability, check out the Zaurus.

David Abrahamson is a major in the U.S. army, stationed in Japan.