CPU Usage in NTVDM

[xiong]

Here goes:

Using Windows 2000 Terminal Server
Running 16-bit FoxPro Application
Windows 2000/XP Workstations

Problem:
When a user switches from the TS FoxPro application to a local application and then back, the system has interpreted the ALT keystroke and accessed the menus in the app. When the user taps the ALT key again to de-select the menu, but touches nothing else, the server CPU pegs out at 100%.

Other application do not exhibit this behavior, running with Citrix MetaFrame does not produce the problem. Inactivity in the app also seems to cause the problem, but intermittently and I have been unable to reproduce.

Assume latest hotfixes and patches on servers and workstations.

Any thoughts?

 

[mattjurado]

16bit apps always use more system resources than 32bit, have you contacted the manufacturer/vendor of the product? It may not be fully compatible with Terminal Services. Also, Foxpro and Access apps tend to have memory and CPU usage issues.

Matt

 

[xiong]

Actually, we are the vendor. And we've tested as thoroughly as we thought possible, but just came across this anomoly. There's nothing in the source code running any polling, or keyboard commands at the time.

This can only happen with one user logged into the app, and we run a dual processor 2.6 GHz with 2.5 GB ram. Granted a 16-bit app only uses 16-MB max, but we're no where near that threshold either.

 

[mattjurado]

Above you day "running with Citrix MetaFrame does not produce the problem." Does this mean the problem only occurs on RDP sessions, and not ICA sessions? Also, does this happen if you're physically sitting at the server console, or just via Terminal Services?

Matt

 

[xiong]

Only via Terminal Server over RDP at this point. I've been trying to duplicate the problem in other environments, but have been unable to do so as yet.

 

[mattjurado]

Have you tried reducing the encryption levels and disabling all the unneeded mappings (i.e. sound, com, clipboard, etc...)? Other than playing with the RDP settings, try searching thethin.net

Matt