Monitoring begins as soon as the services are hooked, and the statistics gathered by VxDMon‘s VxD can be imported into the user interface by choosing Options|Update Statistics in the main window. The latest statistics are read from the VxD by selecting Options|Update, and reset to zero by selecting Options|Reset. Depending on the value of the Preferences|Zero Statistics on Update selection, Options|Update either accumulates the counts (off), or gives the counts since the previous Update (on).
Control-flow information can be seen by double clicking on a service in the main window, or by highlighting a service and choosing Options|Show Ancestors or Options|Show Descendants. A services ancestors are all services that preceeded the service in the control-flow. The immediate ancestors of a service include all the services that directly called it. Correspondingly, the descendants of a service are those services that followed it in the control-flow. The immediate descendants are those services that were directly called by the service. When ancestor or descendant information is selected, a new sub-window is opened that displays the control-flow hierarchy as a tree-view. The same ancestor/descendant selection facilities are available in the sub-window so that other services can have control-flow windows opened for them. Finally, both the main window and the control-flow windows have save capabilities that dump the windows contents in formatted ASCII to a file.
VxDMon includes full on-line help that describes these steps in detail. It also tells you how you can add information about your own VxD to VxDMon‘s database in order that VxDMon can monitor your own VxD services.
This is a screenshot of VxDMon‘s statistics for a sample of typical Win95 activity, and a call-graph showing VxD services that invoke a particular VMM service.
Source Code
VxDMon comes with full source code. Unlike many of our other Windows 95 VxD‘s, VxDMon is written in assembly language so you can build it with the Windows 95 DDK. The VxDMon GUI was built with Visual C++ 2.x.
