Published on: Sunday 5th September 1999 By: Janus Boye
Wouldn't it be cool, if we could have a simple hypertext system on our PDA's?
Imagine being able to enter a meeting in your calendar, and having that linked to the address of the meeting in your address book, plus linked to your meeting notes, and an email you received about the meeting.
The display on PDA's are way too small to have several different 'windows' open, and thus you cannot just switch between 'windows' to easily see both the event, the address, the note, and the email. Currently you have to first find the event in your calender, then find the address in your address book, then find the note in your note book, and then finally find the email in your email program.
This short article will cover how a such system could be implemented, and some issues that would have to be taken into consideration when implementing a such system. As I only have a Palm, this article is mainly written around this platform, but notes on how the ideas presented in this article could be implemented on other operating system are more than welcomed.
Basically, the idea is to hypertext enable PDA's. PDA's such as Palm's and Nino's has become extremely popular in the last few years, and it is no longer just a geeks toy, but is turning more and more mainstream.
On the market you can already now find Web browsers for your PDA's. New Windows CE Nino's comes preinstalled with Internet Explorer, and several Web browsers exist for Palm's. Putting the Web onto PDA's is an important task, but it could be even more interesting just to hypertext enable the core applications that people use on their PDA's: Calendar, Address Book, To Do List, Notes and Email.
In what you do every day, these different activities are intertwingled. Addresses are connected to events, notes can be connected to your To Do List, items in your To Do list can be connected to entries in your calendar, emails are connected to persons, anniversaries and birthdays are connected to addresses, and so on and so forth. The problem is, that once you turn these things into digital form on your handheld, the device does not see the connections, and thus you are unable to easily travel between between these applications, and create the shortcurts and links that exists in the real world.
While the idea might sound simple and useful, PDAs have limited memory, that might not allow us to build a fancy rendering or editing tool, and they also have very limited screen real estate. It is also hard to enter data onto the device, so it needs to be real easy for people to make the connections.
Other than addressing the physical limitations, one also needs to consider the more traditional issues with hypertext systems; How do you avoid broken links? Are links one-directional or bi-directional? Is transclusion possible?
Based on studies of how users interact with their PDA, some of the issues that implementor should consider would also be how to avoid scrolling,
One of the reasons that PDAs have taken off, are mainly their usage as information appliances. Most users enter most of their data on their desktops, and then synchronize this onto their PDA, which they then use when they are on the road. Some office applications (i.e. Microsoft Office) allow some degree of linking between the different core applications while others don't. The important thing here, is to make sure that any links created on PDAs are preserved when users do a synchronization. While it is acceptable that PDA links are not carried over to the desktop, links needs to be preserved, even though the synchronization updates data on the PDA.
Lastly, and perhaps most challenging, implementors should consider writing something that would work on the many different PDA operating systems that are out there. Making it work on Palm OS, Windows CE, Nokia Communicator, and even future devices with future operating systems, would extend the reach of the hypertext system tremendously, but are much more sophisticated than just the relatively easy fix, which would be to fix the Phone Lookup function (more about this in the next section).
If you are working on a Palm, you already have the build in Phone Lookup function, that allows you to look up persons in your address book, from within the other applications except Email. While this is a nice feature, the problem is that it does nothing more than what the functions name implies. It simply just finds a persons phone number for you and lets you add that to entries in your calendar, to do list and to your notes. If you update the persons contact information (e.g. changes his/her phone number), the entry is not updated in the other applications, and the name is not a link to the address book.
If you want to get started writing code, and want to develop to the Palm platform, you are able to get the entire OS source code from Palm's web site. This should allow you to interact with the 4 core application
A different approach to integrating the core PDA applications could be to create a truly Web-based application that had the applications, plus was able to synchronize with the users PDA. The main benefit with this approach, is that it would work on any device that has a Web browser, be it PDA, desktop or boombox. The main obstacle to it, is to synchronize onto the PDA, and being able to also update on the PDA.
A future implementation could make email on PDAs fully hypertext enabled, or could even extend the reach of the hypertext system onto the desktop.
Some of the ongoing work on this front, is to use Ted Nelson's legendary ambitious hypertext project Xanadu on handhelds