This sounds like a setup that would fit a lot of small businesses.
There are such things as Linux PDAs.
But that assumes a live connection.
If via Bluetooth or cellular modem, then you just use the web browser.
If the pocket PC has a database subset, as you suggest, that assumes an asynchronous connection.
(Any MUMPS with TCP capability should be able to use HTTP or talk to VB or Java front end.)
It would be nice to see MUMPS running on a Linux pocket PC.
Given the small amount of memory (2-128Mb) that such hardware usually has, I don't know
that any implementation exists.
(Of course, on a mini-computer, 64 Mb would be plenty.
I guess the web browser uses a lot of RAM.)
An all RAM database would be needed too.
It would be ideal to have the same business software work from the desktop PCs.
If it could be MUMPS and a web browser on both, that would be great.
The key to solving this problem seems to me to be how to browse and update the data
on the pocket PC.
If not MUMPS, then what?
This setup could work identically on a desktop except that the local data subset could retrieve and refresh instantly to the MUMPS server.