Re: Data table text I/O package?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 23 Jun 2005 13:37:20 +0200, Georg Bauhaus wrote:

> Dmitry A. Kazakov wrote:

>> CORBA, OPC (hmm), RPC etc, Ada.Streams after all.
> 
> How does one debug data passed using RPC etc, for example
> when the P could not be called due to some data error?

There should be no difference to debugging conventional calls, objects
(depending on the paradigm.) I would readily agree that available
middlewares aren't that good. We have our own, just because CORBA and OPC
don't fulfill our requirements.

Returning to the point. In our middleware you can monitor each byte sent or
received for any hardware interface. It is an integrated functionality. You
can also see a summary of how pieces these raw data were interpreted as the
application level values: velocity, temperature etc. Viewing some complex
hierarchical structures was never requested. Maybe because there is no any
(:-)), but largely because when it comes to debugging, timings and
relationships *between* values are of much greater importance. Typically
there is some periodic activity that involves values x1, x2, ..., xN, say,
each 10ms. The range checking subsystem reports that x34 violates its
bounds. That happens once per hour [rather an easy case, in one real case
it was once per 3 months.] So, you turn logging on, and try to analyze the
system state around these points. That's nasty! Protocol errors are trivial
compared to that. Honestly, I cannot remember any difficult case, though we
are supporting many quite strange devices. It might sound as an anecdote,
but in one case we indeed used print-outs read from a serial port! There
was no other way to access the device data, than through its serial
printer. We were lucky that the printer wasn't used in the graphic mode...
(:-))

The situation would change if more complex (OO) structures were involved.
But I don't think that XML would be an answer. I would prefer an OO-ish
approach where each object knows how to construct itself out of a segment
of raw data.

> Some XSL "primitives" are quite powerful, when compared
> to Ada "primitives".

There is nothing more powerful than a call to the procedure Do_It! (:-))

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de