Serial Problem on Mac G4

[sgonzo@my-deja.com]

I have been running an experiment successfully on a 604e machine (power
computing mac clone) which basically reads 12 scales through a serial
card, and reads input and writes outputs through SCXI 1160 and 1162HV in
12 slot chassis. It polls the scales constantly through calls to the
serial ports (init at program start, write port, bytes at serial port,
read port) and the labview programs takes appropriate actions when the
scale weights change.

I'm trying to duplicate the same setup on a G4. The systems runs fine
for hours, and sometime during the night simply halts, though the
computer operating system is still functional, and labview is still
functional in that I can use the "stop sign" to halt the program.
However, no loop
s are active. The whole program has just stopped
progressing.

The working system is:
Power Computing 604e based system
NIDAQ 4.8.7
Labview 4.0.1
PCI-MIO-16XE-50 card
Mac os 7.6.1
Megawolf Fenris 16 port Serial Card and drivers

The system which halts running an identical program is:

Macintosh G4
Labview 4.0.1
NIDAQ 6.6.0f2
PCI-DIO-96 card
Mac os 9.0
Mac os rom 3.2.1
Megawolf Fenris 16 port serial card and drivers.

I believe the working system has 96 mb of memory. The G4 had 64 mb, and
to eliminate the problem I tried swapping it to 256 mb. This did not
stop the problem.

Any suggestions about the recommended configuration for a G4 - 400 mhz,
or steps to gather further data to determine the problem would be
appreciated.


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Before you buy.

[GANDIT]

the G4 runs faster and sometime I have noted problems with the serial functions.
To solve these problem, I have introduced waiting times (few milliseconds) between read and write functions on the serial port.