Re: Application modernization & re-engineering

James wrote:
I've written parts of commercial applications in both MI and 8086.
But debugging with an oscilloscope?
I've aligned a floppy drive with one, but . . . ???


James -

In 1989 I wrote and was testing an APPC program that communicated between a
System/36 and a Tandem Computer. I think I have possibly mentioned this
before on the list.

The System/36 application was a pilot project for a dispatching system for
Werner Trucking where the dispatchers entered a message via a System/36
program and the System/36 APPC program would send the message to the Tandem
computer.

The Tandem was connected to a radio transmitter and the message was
broadcast into the sky, bouncing off meteor trails (experimental technology,
to say the least) and back to the brick-type terminals in the trucks.

We couldn't get the APPC connection to vary on from the System/36 side when
communicating with the Tandem. We knew the application worked because we
had prototyped the program by creating an APPC program on our AS/400 and had
tested successfully by sending messages from the System/36 to the AS/400.

By putting a data-monitoring device that trapped the communication stream
between the System/36 and the modem, Tandem's technicians finally determined
that they had a bug in their implementation of APPC which, once corrected,
allowed our application to communicate with the Tandem program.

(leading me to believe that we were the *first* to use APPC with a Tandem
computer...).

This technology was abandoned, however - they couldn't reliably send
messages because they couldn't get enough data passed at a time, the
duration of the meteor trails was too short, and it took too many retries to
get the message to the truck.

- sjl