Re: "Ada and C++", from comp.software-eng

[barriost@...!asuvax!gtephx (Tim Barrios)]

In article <5148@dftsrv.gsfc.nasa.gov>, abdlm@dftsrv.gsfc.nasa.gov writes:
> Erik Naggum writes
> >>As to the fourth claim of yours, you could try getting in touch with
> >>Bjarne Stroustrup and ask him about places it's being used.  Last time
> >>I heard, central telephone switching gear (the size of 5ESS) is coded
> >>in C++.  After all, this _is_ AT&T...  These animals implement CCITT
> >>Signalling System number 7.  The specs are 1500 (A-sized) pages of
> >>gory details and 500 pages of verification and validation suites.  I
> >>posted the table of contents of SS7 to comp.std.internat some time
> >>ago.
> 
> Wasn't this the system (or one similar to it) that took out the whole east 
> coast of the U.S. with a pointer bug last year. Chalk up another victory for
> the power of pointers and C++. With so much of the world economy riding on
> the telecomunications networks, wouldn't it make sense to build these 
> systems with tools (read languages) that were designed for reals time systems.

i don't think much (any?) of the #5ESS switching system is written in
C++.  it's generally written in C.  i work for a company that develops
a competing product (GTD-5) that is written in a specialized,
real-time, embedded version of Pascal (sort of pre-Ada, Ada; a "real
language"). [we used to be a competitor to AT&T but now we're part of
them since are now a JV between AT&T and GTE]

the bug that brought down the switch which "took out the whole east
coast" was related to a C 'switch' statement that was missing a
'break'.  so, when the code jumped to the particular case, it
continued into the next 'case'.  not being a big fan of C, i found it
quite amusing.

i have heard it said that the cost of maintaining our switch tends to
be less than that of AT&T.  could it have anything to do with the
language used?  just a thought.

Disclaimer: these are my own personal views; certainly not the views
of my employer.
-- 
Tim Barrios, AG Communication Systems, Phoenix, AZ
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