NPDS Tracker Client


Whatif you had a Newton WWW Server and nobody came? I mean, maybe theywould want to, but how are they going to know your IP address?

We have a solution. When you go online, your Newton can nowregister with a tracker. People who want to find Newtons onlinesimply visit the tracker and they'll find a link to your Newton ifits still active.

NPDS Tracker consists of two applications that communicate witheach other.. Tracker Client (which is a NPDS plugin) and TrackerServer which is a MacOS CGI/daemon hybrid.

When NPDS starts up, Tracker Client is activated by the NPDSarchitecture and told to register. It sends, using a specialprotocol, information needed to find your Newton on the net as wellas a description of your Server. The Tracker Server records thisinformation for later use. Your NPDS continues to start up and that'sit, from your Newton's end of things.

On the other end of things, Tracker Server is busy. People whowant a hyperlinked list of Newton servers are accessing it with theirWWW browsers while it is also constantly monitoring the status ofeach Newton that has registered with it. If a set period elapseswhere Tracker Server can't connect to your Newt and retrieve aspecial page (served by Tracker Client), it is removed from the listof active Newton servers. The ususal period for this expiration is 45minutes to one hour and a Newton is usually given 3 chances torespond before being removed.


Use you favorite package installer to load Tracker Client onto thesame store as all the other NPDS components. If you wish, install aNPDS Tracker Configuration package to pre-set all the prefs for you.Once Tracker Client is configured, it functions automatically onserver startup.


Manuallysetting up Tracker Client is also easy:

You'll notice you also have a checkbox called "Register With ATracker". If this box is unchecked when NPDS starts up, TrackerClient will NOT log into its specified Tracker Server.

You can easily remove yourself from a Tracker (after an expirationperiod has elapsed) by de-selecting this checkbox. Conversely, if youare running your server and decide after starting it up that you DOwant to be on the tracker, turn this on and tap the "UP" icon at thebottom of the window to manually transmit your data to the TrackerServer.

The Slash-Circle icon is for cancelling a connection that seems tohave gone awry. I have never needed to use it but it's still there incase of emergency.


Once you're ready to go, open up nHTTPd and start it up as usual.The status line will progress from IDLE to INIT andpause for a bit. A NIE status dialog will pop open twice (that'sTracker doing its job), then the status line will read READYand you'll be all set. To verify that your server has registered,point your browser to you'll see a page pointing you to the tracker. Click the link andsee what develops: if all went well, your Newton is listed happily onthe tracker!

Verification by Tracker Server:


After a few minutes (15-30 minutes), Tracker Server will come by and ask for a special response from the /traq/ directory. If its request is fulfilled, your Newton's lease on life at the tracker will be renewed for one expiration cycle.

You'll know this has happened because the status icon of nHTTPd will change from the standard Connected icon to the Tracked icon.

This verification will continue until your Newton no longer responds to requests from the Tracker Server.



No major problems have been reported. If you're on a long time,NPDS can tend to slow down, or if you have a very active server. Ineither of these cases, you may find yourself wrongly removed from theTracker. To get back online, just open the Tracker client and tap theUP icon.

Running Your Own Tracker

The Tracker server is a CGI that runs under any MacOS Web Serverthat supports the standard Mac CGI model (Personal Web Sharing,WebSTAR, NetPresenz, etc). It'll run on a 68K but due to some minorglitches, it's not supported on that platform. If you're interested,email me at andperhaps we can get you set up.