Alsys question + CAIS comment

Alsys question + CAIS comment

[larry]

One group I'm helping has an Alsys Ada compiler for the AT and needs to 
import math and other routines.  Has anyone solved this problem already?  If 
so, we'd appreciate whatever help you can give (even copies of sample code 
without explanation would be helpful).
==========================================================================

Several people have (rightly) taken me to task for suggesting a requirement 
for the Space Station SW Development Environment of "an operating system 
easily updated to the CAIS."  Of course, that has to be restated in more 
specific terms, and in such a way that compliance can be measured.

However, I doubt if any input to the Space Station management would 
have any effect.  They seem to be firmly committed to IBM mainframes running 
MVS.  It's what they've used with much success in the past, and people in the 
space program are (contrary to popular expectation) extremely conservative.  
Further, there are some very rational reasons for wanting IBM hardware and 
MVS operating system.  Most of their people are expert in their use and won't 
require expensive, time-consuming re-training with all the attendant chances 
for catastrophe before becoming expert; a whole suite of SW-engineering 
tools are available from the shuttle program; and they don't have to worry 
about the vendor going out of business.

Actually, I suspect the probability of many people ever using the CAIS is 
pretty small.  The CAIS has a competitor that's already won the de facto 
status of an industry-wide standard, being used by 70-80% of all programmers 
in the U.S.  And its supported by a vendor which stands to lose billions 
of dollars each year if an operating system standard is chosen that 
makes it easy to port SW to other vendors hardware.  No, it isn't Unix and 
AT&T (which many supporters of the CAIS seem to consider their bete noire,
judging from all the argument against it I hear).  Its MVS and IBM.

                                                Larry @ jpl-vlsi.ARPA

Re: Alsys question + CAIS comment

[alden]

Larry,

The arguement that "everyone knows MVS and IBM" so lets stay in the middle
ages is most likely not going to wash as a reason to get out of the
now Ada and soon CAIS requirement of DoD contracts.  Time will tell.  Most
programmers do not interface to a significant extent with the underlying
O.S. but rather use tool sets which differ from O.S. to O.S.: e.g. on
Unix the popular editor is VI, on VMS its ED, on CPM its Wordstar, etc.
Nothing precludes these tools being written in Ada and ported to the CAIS
if the cost of retraining a given staff is higher than rehosting these
tools.  

Thus from an O.S. point of view, I find the arguement of training
cost not valid.  The CAIS is to be used with Ada programs and the harder
of the two to learn is Ada, not the CAIS.  In addition, how much of the 
programming population writes tools?  Small portion. Most of the difficult 
parts of the CAIS lie in those routines that will support tool writers in 
writing tools and not for those writing code to be run on target machines.
The average programmer is not going to have to learn all that much to
survive and produce good reliable code.

If your complaint is that Ada can't be learned, that is another arguement.
Personally, it's been my experience that the transition is not as painful
as those who have yet to make the transition complain about.  Further,
for those who have worked on an Ada project, its been my experience that
they prefer the language over others.

Finally, no one has ever been able to show me statistics for a medium to
large scale project where the total time (design, cost, test, and maintenance)
was more using Ada VS other languages (Fortran, etc.) where the time
was due to having to learn Ada.

If Everyone agrees that there is a "software crisis" and that the cost
of developing software is too high, then these same people must not 
argue for doing nothing - which is what not having to learn something new
implies.

	...Tony Alden
           TRW


The above stated views are my own and do not reflect those of TRW or any
management connected to TRW or any person living or dead connected to TRW.