Re: ASIS (Was Re: IrisAda)

[noc.near.net!inmet!ryer@uunet.uu.net (Mike Ryer)]

Bear in mind that ASIS has a cost beyond the dollars you pay for it.  It
can result in slower compilers and larger program libraries.

Our compiler (for MVS) currently generates DIANA; it would be a very simple
matter to add ASIS generation -- just send money.  However, I've been lobbying
in-house to scrub down the DIANA to a much simpler internal form, deleting a
lot of the attributes that are only there for use by future tools.  This would
make the compiler a lot faster and the libraries at least a factor of three
smaller.

Telesoft and Rational have technology which generates and retains a lot of
data in the libraries.  Providing an ASIS interface is convenient for them.
Vendors who have, or wish to have, leaner compilers may not be able to meet
the ASIS specification.  We estimate that supporting ASIS requires that the
compiler generate and retain over 1000 bytes of information per line compiled.

In my opinion, ASIS has been defined as "everything that Telesoft and Rational
happen to have in their libraries", rather than "everything that a reasonable
tool vendor needs and cannot easily compute for him/herself".

I'd rather see Ada compilers become as small and fast as C compilers than
see richer tool support.  ASIS precludes small and fast.  I'd rather see
Ada compilers get cheaper, instead of providing more functions.  ASIS will
cost something to implement; increase the size and complexity of the compiler
source code that has to be maintained; and, no doubt, create an additional
validation burden eventually; I think that small/fast/cheap would be better 
for the acceptance of Ada than ASIS support could ever be.

These are just my opinions -- I don't control the direction of Intermetrics'
compiler technology.  Our customers control it through their purchasing
habits.  If you talk to us, we'll tell you that ASIS support means slower
compilers and bigger libraries and let you make the tradeoff.  If you just
put it in your RFPs, standards, or regulations without asking the cost,
we'll comply, whatever the cost.

So please, don't jump on the ASIS bandwagon too fast.  At least wait until
more than one vendor implements it.  See how well it works on your PC's and
in your large projects.  Find out whether users turn the ASIS option off
in order to get their work done.  If ASIS's cost in size and speed are
acceptable, then it's a good thing.  But that is yet to be demonstrated.


Mike Ryer
Intermetrics