A farewell to Ada

A farewell to Ada

[Ted Holden]

 
 
 
      I've noticed that much of the present scholastic debate over Ada
involves fine points concerning the letter of the law (was Ada "intended"
to function in embedded systems etc.).  This is the kind of thing I expect
to see associated with losing causes.  Remember, the Apostle said
something like: "The letter of the law killeth, whereas the spirit giveth
life..."  People involved with winning causes are usually too busy making
money to be arguing over the letter of the law.
 
      The spirit of the Ada documents was never in doubt.  What was wanted
was a language which could be used for every kind of software project,
from embedded system to large database, and run on every kind of computer
system, from micro to mainframe.  Reasonable performance was expected on
all computers and for all projects.  Ability to run with minimal OS and
other language support was wanted.  Further, logical clarity and large-
scale re-usability of software was desired.
 
Journal articles indicate a continuing failure of Ada to work for embedded
systems as well as for large scale projects, a continuing failure to run
with acceptable performance on anything other than parallel or special-
purpose, expensive systems, and an actual gain in cross-system complexity
and decrease in the stated goal of reuseability.  In particular, the
ordinary systems which most people will be seeing in front of them for the
next 5 - 15 years, UNIX systems and PCs, will not run Ada accepteably.
 
C began with real machines, real programmers.  The idea seems to have
been:  
 
      "Lets take a hard look at this little PDP-7 and design a language
      which is one-to-one with its logical operations as many ways as
      possible (the plus-plus operator and register increments and so on)
      so that the code is as FAST as can be contrived, maximally easy to
      implement (so that next year when we get our PDP7.5 or whatever,
      we're back rolling in 2 weeks), and, within these constraints, is
      as amenable to human logic as possible in a no-nonsense, point-and-
      shoot kind of way, so that we end up with a kind of high-structured,
      low-level language; a thinking-man's assembler.  And then, let's
      write an operating system (UNIX) in that language so that, when we
      get our PDP-7.5, or the next year's computer, whatever it may be,
      we're REALLY back rolling two weeks later.
 
The maximal ease of implementation was achieved by making the core
language as small as possible, other functionality being left to the
operating system and to libraries, some standard amongst UNIX systems and
others peculiar to various other OSs and hardware bases for which C would
be implemented.  This allowed good and inexpensive C compilers to evolve
rapidly for PCs and other micros and, since the authors of those compilers
maintained the standard libraries as close as possible to the UNIX
implementations, C became the natural bridge between mid-sized and large
computers running UNIX and the micros.  
 
C thus achieved its present position of dominance in the mini-micro world,
and appears to be well poised for the future as well.  C++ appears to be
an entirely rational and intelligent extension of C, superimposing the
entire object-oriented paradigm including the features Ada leaves out.  
In particular, there appears to be no more than a 5% performance
degradation, if that, going from C to C++, at least judging from Turbo C
2.0 and the Zortech C++ compiler, and I assume the same will hold true
when you start seeing good native-mode C++ compilers for UNIX.
 
In fact, C++ appears to BE the very language which Ada was supposed to be
(the spirit of the law) but never can and never will be.  
 
Far from sharing this "real-world" sort of a heritage, Ada appears to have
its beginnings on the other edge of reality or non-reality, dependant on
one's point of view.  Ada appears to have been designed as a physical
embodiment of state-of-the-art principles of "software-engineering",
whatever that's supposed to mean, seemingly by assembling 300 committee
members in a room, having each draw up a maximum possible wish-list of
features for a programming language and/or operating system, and then
adding up all of the lists to a "standard", with any considerations of
real-world computers being regarded as unimportant. 
 
Ada is what you might expect from a programming language designed by
committee;  it is unbelievably slow, an unbelievable resource hog,
involves constant dilemmas over which is the real OS today, Ada or UNIX,
Ada or Dos etc. i.e. do we use Ada tasking, again frighteningly slow, or
ordinary UNIX tasking and inter-process communication, Ada source control
or SCCS, etc.  Naturally, the Ada task manager and the UNIX process
scheduler clash.  As for compiling, my experience has been that, with a
PC and lots of memory to play with, Ada compilers at least will get back
to you on the same DAY;  on a UNIX machine with ten other users doing
various other kinds of things, God forbid other Ada compiles, forget it.
 
The one thing which one might reasonably expect all of this slowness and
clunk to purchase, the one thing which might partially redeem the
situation were Ada to have it, is the object oriented paradigm: 
inheritance of classes and polymorphism.  Ada doesn't have it.
 
Most of the Ada journal articles begin with glowing headlines, and you
have to be able to read between the lines, but this isn't terribly
difficult.  For instance, a large section of articles in the December 88
Journal of Electronic Defense began with the title "Ada:  Maybe Not So Bad
After All". Remember, Ada has been around since 1979.  If that were the
best anybody could say about C after ten years, C compiler salesmen would
be starving and dying like flies.
 
     A senior Intel product marketing engineer is quoted on page 36 of the
same issue:  
 
      "the people who designed the Ada programming language were compiler
      experts, software experts - they weren't necessarily people familiar
      with real-time embedded systems."
 
Another article in the same issue describes the use of Ada in connection
with a real-time embedded digital signal processing application.  Since
Ada tasking could not be made fast enough for such work, the engineers
adapted a commercial run-time system, VRTX, and informed all programmers: 
 
 
     "Thou shalt not use Ada tasking, but rather VRTX tasking.
     "Thou shalt not use Ada dynamic memory allocation...
     "Thou shalt not use Ada generics; too slow...
 
and, when they finished with the "Thou shalt nots", what they had
left of Ada was a subset of Pascal which they had paid many thousands of
dollars for.  A far better Pascal compiler is produced by Borland and can
be had at B Dalton's for around $100.  Needless to say, the Rupe-
Goldbergesque system they ended up with was considerably less maintainable
than they might have gotten just using C.  This seems to be the rule.
 
The September/October 88 issue of Defense Computing carried a similar
article:  "Running in Real Time:  A Problem for Ada".  All other stories
concerning Ada and embedded systems read similarly.
 
     Does Ada work any better for large scale systems?  Another article
in the same Journal of Electronics Defense issue describing use of Ada on
the 1,246,000 line Army AFATDS system claims that:
 
      "Ninety percent of the software requirements were met with no major
      software problems."
 
as if this were good.  The man is claiming that he had major language-
related problems with 124,600 lines of code out of 1,246,000.  Again C
language is not noted for this kind of thing, nor would C be around if it
were.
 
     There was a recent DOD Computing Journal Article titled "Is Ada
Getting Better or Just Older?".  Again you don't read that sort of thing
about C.  There is the August 21 89 issue of Government Computer News
describing the problems which the huge FAA Advanced Automation System is
having due to IBM Ada implementations and tools (or lack thereof).  
 
     The SoftTech notes from the RICIS convention included mention of one
speaker's statement:  "Ada and UNIX doesn't work".  I've heard that a
million times from users, first time that succinctly in print.  Between
UNIX and Ada, UNIX is the real-world standard;  conflicts between it and
Ada will not be resolved in favor of Ada.  Hate to disillusion anybody...
 
     It would appear that the articles written by the real-time people are
saying "well, it isn't doing us any good but it must be working out great
for the mainframe guys, else why would we still be seeing it and be
ordered to use it?" and that the mainframe and database crowd is claiming
just the opposite.  Somebody must be hoping that nobody ever reads all of
these articles and starts putting two and two together.
 
      There are numerous problems associated with the fact that Ada
believes itself to be an OS, aside from the clashes between Ada and real
operating systems.  There is the further obvious problem that somebody
with a large mainframe/Cobol application which he thinks to port to a
UNIX/Ada system will need to redesign and rewrite his entire system from
scratch whereas, using C language, he might have written Cobol-callable
routines incrementally and had his application back up in a matter of days
or weeks instead of years.  There is no real way to call an operating
system from a Cobol program.
 
      The actual use of Ada is further complicated by three considerations
which really amount to theological problems INVOLVING Ada rather than
faults of Ada itself, but which, nonetheless, probably wouldn't exist if
Ada didn't exist.
 
First, the programming style being promulgated by DOD for Ada is anti-
conducive to the stated goal of readability;  it's like looking at a
thousand-page novel such as "War and Peace" with three or four lines of
programming code interspersed every second page or so.  The verbiage hides
the logic.  When every variable name looks like:
 
      "NUMBER_OF_CROWS_SALLY_ANNS_GRANDMOTHER_SHOT_WITH_HER_12_
      GAUGE_-LAST_TUESDAY",
 
then a single subroutine call (involving several such variables) can take
up a whole page.  In my own scheme of things, I try to keep literature and
programming separate.
 
Second, DOD is often insisting on portability via Ada rather than
portability via UNIX, POSIX calls etc.  This amounts to such things as
insisting, for instance, that vendors provide direct Ada hooks to a
database rather than simply writing an Ada -> C -> database hook.  Typical
vendor response is either "F... You" or "Manana".
 
A third is an over-emphasis on design, which often leads to grief in the
real-world.  I believe in designing in the large, nailing down interfaces
at tightly as possible, then rapid prototyping of individual modules,
followed by final design documentation and PDLs at low level.  I know of
numerous horror stories involving design-totally-then-code, but one very
recent one, naturally involving Ada, seems to top all.  
 
A military project involving Sun machines and Ada was abandoned after
something like 4 years and $30 million effort because of unacceptable
performance;  database screens were taking over a minute to come up.  The
design work had all been done according to your formula, the individual
modules had been designed, written, and tested, all according to the
standard military schedules and formulas (2167 etc.).  Everything seemed
hunky dory, only when they put the fricking thing together, it was too
damned slow to use.  And, the remarkable thing is, the very system the
military insists upon for management of software contracts prevented
anybody from knowing they were in trouble until four years and millions
had been blown.  The government people involved were essentially reduced
to the role of actors in a Greek tragedy.
 
Asked for a solution, my firm weighed the choice between offering an Ada-
to-C converter and silence, and opted for silence.
 
It sometimes seems to me that the Soviet military is kept backwards in
computers by a temporary lack of funds, while our military is required by
law to be backwards, and that may not be temporary.  Any rate, my guess
is that the general Russian skill with linguistics would prevent them from
ever being ensnared with Ada;  they would take one look and toss it. 
Slava Bogu.
 
      Ada threatens to leave DoD stranded and technologically backwards;
out of the mainstream of American computer science.  The better class of
programmers coming out of the schools will be used to the 2 second
compiles of Turbo C and Turbo Pascal.  Offer them jobs involving Ada, and
most if not all of them are probably going to give you the finger,
figuring they'd be happier selling used cars for a living.  
 
      There is the further problem of our present micro market being a
completely open system;  a representative of the KGB, the Turkish Empire,
the Green Dragon Tong, the successors to the AssHola Khomeini, Khadaffi,
or anybody else could walk into a B. Dalton's today and buy a copy of
Turbo C 2.0 or Zortech C++ for about $100.  Again, if I were the guy up
there getting into machine gun and rocket fights at 1600 mph, the last
thing I'd want to hear was that my machine guns and rockets were working
slower and/or less reliably than the other guy's because he bought a copy
of Turbo C at B. Dalton's, while my people were spending billions on Ada.
 
 
Ted Holden
HTE

Re: A farewell to Ada

[schmidt]

In article <14033@grebyn.com>, ted@grebyn (Ted Holden) writes:
>Ada is what you might expect from a programming language designed by
>committee;  it is unbelievably slow, an unbelievable resource hog,
>involves constant dilemmas over which is the real OS today, Ada or UNIX,
>Ada or Dos etc. i.e. do we use Ada tasking, again frighteningly slow, or
>ordinary UNIX tasking and inter-process communication, Ada source control
>or SCCS, etc.  Naturally, the Ada task manager and the UNIX process
>scheduler clash.  As for compiling, my experience has been that, with a
>PC and lots of memory to play with, Ada compilers at least will get back
>to you on the same DAY;  on a UNIX machine with ten other users doing
>various other kinds of things, God forbid other Ada compiles, forget it.

Along the same lines, lately I've heard a number of people make the
claim that:

  `There now exist Ada compilers that produce faster code than C/C++
  compilers.'

Naturally, taken out of context this statement doesn't mean very much,
since one can always find a lousy C/C++ compiler and an application
that brings out the worst in the compiler and vice versa for Ada.

Therefore, I'm curious to know what valid empirical studies have been
performed to compare `x' Ada compilers against `y' C/C++ compilers
across a representative set of benchmarks.  Furthermore:

1. Which `top-of-the-line' Ada compilers produce the best code?
2. How long do they take to compile non-contrived programs?
3. What are their resource constraints and requirements?
3. How reliable are they in practice?
4. And how much do they cost compared to `top-of-the-line' C/C++ compilers?

Without evidence of this sort the entire `language imperialism' debate
becomes egregiously religious.

Obviously, ``speed-of-generated-code'' or ``length-of-compile-time''
are not the only criteria by which to judge the success or failure of
a language.  However, since Ada supporters are beginning to make these
claims I'd like to see some supporting evidence!

thanks,

  Doug

Re: Ada

[William Thomas Wolfe, 2847]

From article <14033@grebyn.com>, by ted@grebyn.com (Ted Holden):
> Journal articles indicate a continuing failure of Ada to work for embedded
> systems as well as for large scale projects, a continuing failure to run
> with acceptable performance on anything other than parallel or special-
> purpose, expensive systems, and an actual gain in cross-system complexity
> and decrease in the stated goal of reuseability.  

   This is blatantly false; consider the November 1988 article
   in IEEE Software ("Large Ada projects show productivity gains"):

      After years of development and an initial skeptical reception,
      many people are now using Ada and saying that they like it...
      The growth in Ada's use has been helped by favorable reports
      from early adopters ("Ada Catches on in the Commercial Market,
      Soft News, IEEE Software, November 1986, p. 81) and by the
      growing number of validated compilers... project results show
      that Ada can greatly increase productivity for large systems...
      [in a 1.2-million-line Ada project] reuseable software developed 
      on the project was counted only once.  Roughly 13 percent of the
      delivered software was reuseable.  This reuse saved 190 man-months
      of effort (a 9-percent savings) and reduced the schedule by two
      calender months (a 4-percent savings)... Productivity for the
      execution environment -- including the operating system, data
      management, information management, communications support, and
      communications interface -- was 550 lines per man-month... 
      Productivity for the applications software... was 704 lines per
      man-month... the average productivity of the 1,500 systems in
      productivity consultant Lawrence Putnam's database: 77 lines
      per man-month (at the 1.2-million-line level)... 

   Sounds like a continuing *success* to me... 
   
> In particular, the
> ordinary systems which most people will be seeing in front of them for the
> next 5 - 15 years, UNIX systems and PCs, will not run Ada accepteably.

   Precisely the point of Dr. Charles McKay, head of the Software
   Engineering Research Consortium, in his Tri-Ada '88 presentation,
   "Standards for the Sake of Standards -- A Recipe for Failure".

   A prime example is Unix; the current POSIX effort aims to 
   standardize 1960's technology, thus resulting in a "lowest
   common denominator" which locks users into obsolescence.

   Ada's problem with Unix is that Unix, being 1960's technology,
   does not properly support lightweight processes.  Modernized 
   versions of Unix (e.g., MACH) which are designed to provide
   such support remove the difficulty.  Note that C or C++ programs
   making use of the same "heavyweight" tasking facility will be
   equally slow, since they rely on precisely the same system. 

   If one does not have to struggle with the limitations of *Unix*,
   then there is a wide selection of Ada compilers which run Ada 
   within that environment quite nicely.  Some, like the Telesoft
   TeleGen2 compiler, have global optimization facilities which
   result in better code than that which can be produced by current
   C compilers (as of Tri-Ada '88). 
   
> C began with real machines, real programmers.  The idea seems to have
> been:  [...] end up with a kind of high-structured, low-level language; 
> a thinking-man's assembler.  

   Yes, as one Usenetter's .signature states, "C combines the power
   of assembly language with the flexibility of assembly language".

   Fortunately, the economics of software development are in favor
   of using considerably higher-level languages.

> C++ appears to BE the very language which Ada was supposed to be
> (the spirit of the law) but never can and never will be.  

   Total rubbish; C++ retains all the low-level and dangerous
   facilities of C, which is obsolescent by modern software
   engineering standards.  As stated by Fairley (Software
   Engineering Concepts, page 228),  

      Modern programming languages provide a variety of
      features to support development and maintenance of
      software products.  These features include strong
      type checking, separate compilation, user-defined
      data types, data encapsulation, data abstraction,
      generics, flexible scope rules, user-defined exception
      handling, and concurrency mechanisms.  This chapter
      discusses these concepts...

   Now C++ has one useful feature which Ada does not: inheritance.
   But it is also (as its designer freely admits) lacking in
   generics and exception handling, and also does not provide
   a means of expressing concurrency in a standardized, portable way. 
   Since tools such as Classic Ada permit the use of inheritance with
   Ada (generating *standardized*, compile-it-anywhere code), this is
   something which can be worked around until Ada 9X brings it in directly. 

> Ada is what you might expect from a programming language designed by
> committee;  it is unbelievably slow, an unbelievable resource hog,

   This has been a property of some early Ada *compilers*, but is
   not a property of the Ada *language*.  Fortunately, compiler
   technology is now capable of delivering tight, efficient Ada
   object code, better than that being produced by C compilers.

   Compilation is slower because the Ada compiler is doing much
   more work for you; this reflects again the economics of software
   development in that machine time is cheaper than programmer time.

> [...] There is the August 21 89 issue of Government Computer News
> describing the problems which the huge FAA Advanced Automation System is
> having due to IBM Ada implementations and tools (or lack thereof).  

   Are you saying that this is the fault of the *language*, or of IBM?

> There is no real way to call [Ada] from a Cobol program.

   Ada users can call COBOL or any other language using pragma
   INTERFACE; COBOL needs to have a similar standardized means
   of calling other languages.  Given that it does not, ad hoc
   means of calling other languages have been devised; there is
   no reason why such techniques cannot be used to call Ada just
   as well as C or any other language.  But this is COBOL's problem,
   not Ada's.  
    
> the programming style being promulgated by DOD for Ada [descriptive
> variable names] is anti-conducive to the stated goal of readability;  

   To C hackers, who are accustomed to single-letter variables, yes.

   Software engineering specialists tend to have the opposite perspective.

> Second, DOD is often insisting on portability via Ada rather than
> portability via UNIX, POSIX calls etc.  This amounts to such things as
> insisting, for instance, that vendors provide direct Ada hooks to a
> database rather than simply writing an Ada -> C -> database hook.  Typical
> vendor response is either "F... You" or "Manana".

   And the response of the Ada community is to turn to companies
   such as The Ada Ace Group, Inc., a technical consulting company
   specializing in the development of Ada interface to software
   products and applications.  They provide customized pure Ada
   interfaces to existing commercial software products, such as
   databases, operating systems, and specific applications such 
   as X-Windows.  (Contact information: 4254 Indigo Drive, 
   San Jose, CA  95136; (408) 267-8296)  Do you really think the
   Ada community, with its emphasis on standardization and vendor  
   independence, is going to be stopped by an intransigent vendor?

> A military project involving Sun machines and Ada was abandoned after
> something like 4 years and $30 million effort because of unacceptable
> performance;  database screens were taking over a minute to come up.  The
> design work had all been done according to your formula, the individual
> modules had been designed, written, and tested, all according to the
> standard military schedules and formulas (2167 etc.).  Everything seemed
> hunky dory, only when they put the fricking thing together, it was too
> damned slow to use.  And, the remarkable thing is, the very system the
> military insists upon for management of software contracts prevented
> anybody from knowing they were in trouble until four years and millions
> had been blown.  The government people involved were essentially reduced
> to the role of actors in a Greek tragedy.
>  
> Asked for a solution, my firm weighed the choice between offering an Ada-
> to-C converter and silence, and opted for silence.

   How about applying a profiler and recoding the "hot spots"?
   If the slowness of Unix process handling is a problem, then
   a more modern version of Unix should be used.  Your company
   should have considered more than two options.

   There are problems in the government management process, but
   this pertains to the government and not to Ada.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada & IBM

[William Thomas Wolfe, 2847]

>> [...] There is the August 21 89 issue of Government Computer News
>> describing the problems which the huge FAA Advanced Automation System is
>> having due to IBM Ada implementations and tools (or lack thereof).  

    Apparently IBM has now changed its tune; its recent brochure
    entitled "Ada and IBM... Capability and Committment" states:

      IBM is committed to Ada.  Ada's support for modern software
      engineering concepts, its breadth of application, and its
      support for reuseable software components place it squarely
      in the forefront as a language of choice for both IBM's
      software engineers and for IBM's customers.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada & IBM

[ryer]

Last I heard, Ada is not on the list of _acceptable_ languages for IBM's
SAA (Systems Application Architecture?) applications.  (SAA is IBM's big
new advance in portability and interoperability and a fundamental part
of their strategy for computing in the 90's).  If a program
is coded in Ada, it can't comply with SAA, regardless of any other
compatibility or interfaces.  Has this changed?  It is easy to write
a brochure, but where's the beef?

Mike Ryer
(personal comment, not endorsed by my employer, Intermetrics)

Re: Ada & IBM

[William Thomas Wolfe, 2847]

From ryer@inmet.inmet.com:
> Last I heard, Ada is not on the list of _acceptable_ languages for IBM's
> SAA (Systems Application Architecture?) applications.  

   According to IBMers at Tri-Ada '89, Ada runs on three of the four
   platforms required for SAA-hood, and they're working on the fourth.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu
 

Re: Ada & IBM

[Jerry Callen]

In article <20600018@inmet> ryer@inmet.inmet.com writes:
>
>Last I heard, Ada is not on the list of _acceptable_ languages for IBM's
>SAA (Systems Application Architecture?) applications.  (SAA is IBM's big
>new advance in portability and interoperability and a fundamental part
>of their strategy for computing in the 90's).  If a program
>is coded in Ada, it can't comply with SAA, regardless of any other
>compatibility or interfaces.  Has this changed?  It is easy to write
>a brochure, but where's the beef?
>

>Mike Ryer
>(personal comment, not endorsed by my employer, Intermetrics)

Hi, Mike! Actually, the "SAA Languages" are just the languages
that IBM is promising to keep _compatible_ on all of the SAA "platforms."
(Geez, I hate that psuedo-word.) Just because a language isn't supported
by IBM as an SAA language doesn't mean you can't _use_ the language on
an SAA system. In particular, I think it behooves IBM to come up with a 
standard set of Ada bindings to the various SAA subsystems (communications
and database, especially) that WOULD be portable across the SAA
platforms. After all, Ada is already totally portable, eh? :-)

-- Jerry Callen
   ...!{uunet, gould, maybe others}!encore!jcallen
   jcallen@encore.encore.com

   Do what you want to with my signature, but leave my employer alone!

Re: Ada & IBM

[Dick Dunn]

billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe,
2847 ) writes in response to Ted Holden's comments about problems...
> >> ...due to IBM Ada implementations and tools (or lack thereof).  

>     Apparently IBM has now changed its tune; its recent brochure
>     entitled "Ada and IBM... Capability and Committment" states:

>       IBM is committed to Ada...

So what?  First, Ted did not address the question of whether IBM is
committed to Ada; he was talking about a report of real-world problems.

Second, "commitment" is not measured by glowing words in a brochure.  Do
you really think IBM would put out a brochure that said "Well, we're not
really keen on Ada, but it looks like we need it..."?

Wanna buy a bridge?  I'm committed to selling you the finest bridge.  It's
got support for modern engineering...hey, it supports lots of things.  It's
got breadth of application...you can apply it to any need as broad as the
bridge is wide...

Sheesh...it's marketing.  Do you believe every piece of advertising you
read?  Find out what's behind it.

What has IBM got for Ada?  Better yet, if you want to measure commitment,
find out how much new software THEY're writing in Ada (as opposed to
assembly language, or PL/S, or C, or...)

Do you really want a bold commitment from the company that gave us PL/I?
(Save the flames...yes, I know a lot of good software was written in PL/I.
It's still uglier than yesterday's roadkill.)
-- 
Dick Dunn     rcd@ico.isc.com    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...`Just say no' to mindless dogma.

Re: Ada & IBM

[William Thomas Wolfe, 2847]

From rcd@ico.isc.com (Dick Dunn):
> What has IBM got for Ada?  How are they using it?

   Compilers, a comprehensive Ada Programming Support Environment, 
   interfaces to IMS/VS, DB2, SAA, and SQL, an Ada equivalent of 
   CICS (called Ada Interactive Services), and so on.  Further info
   can be obtained from the IBM Ada Help Desk (1-800-387-0262). 

   IBM's Systems Integration Division is doing Ada projects in 
   its Colorado, Maryland, Texas, Virginia, and New York locations,
   ranging from embedded and real-time systems to commercial systems.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada & IBM

[Liam R. E. Quin]

billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu wrote:
>    [...] "Ada and IBM... Capability and Committment" states:
>      IBM is committed to Ada.  Ada's support for modern software
>      engineering concepts, its breadth of application, and its
>      support for reuseable software components place it squarely
>      in the forefront as a language of choice for both IBM's
>      software engineers and for IBM's customers.

No doubt the simple elegance of Ada appealed to IBM, depite their well-known
dislike of such small languages.

Lee

:-)
-- 
Liam R. Quin, Unixsys (UK) Ltd [note: not an employee of "sq" - a visitor!]
lee@sq.com (Whilst visiting Canada from England)
lee@anduk.co.uk (Upon my return to England at Christmas)

Re: Ada & IBM

[William Thomas Wolfe, 2847]

From lee@sq.sq.com (Liam R. E. Quin):
>>    [...] "Ada and IBM... Capability and Committment" states:
>>      IBM is committed to Ada.  Ada's support for modern software
>>      engineering concepts, its breadth of application, and its
>>      support for reuseable software components place it squarely
>>      in the forefront as a language of choice for both IBM's
>>      software engineers and for IBM's customers.
> 
> No doubt the simple elegance of Ada appealed to IBM

   Actually, it's rather surprising, since their background has
   largely consisted of primitive languages which offer little
   or no support for the software engineering process.  It's good
   to see IBM finally recognizing this major advance in software 
   engineering technology.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada & IBM

[Liam R. E. Quin]

[I wrote]
>> No doubt the simple elegance of Ada appealed to IBM
[Bill Wolf wrote]
>   Actually, it's rather surprising, since their background has
>   largely consisted of primitive languages which offer little
>   or no support for the software engineering process.  It's good
>   to see IBM finally recognizing this major advance in software 
>   engineering technology.

Uh, did I leave off the :-) signs?  I was not being serious. 

Let's not start religious Ada vs. <whatever> quarrels.
[mail me if you absolutely must, I'll try not to take EXCEPTION :-)].

Lee


-- 
Liam R. Quin, Unixsys (UK) Ltd [note: not an employee of "sq" - a visitor!]
lee@sq.com (Whilst visiting Canada from England, until Christmas)
Software engineering is largely a philosophy, a state of mind.

Re: Ada & IBM

[Ken Ritchie]

Recapping: IBM has elected to pursue Ada, surprising some folks(?) :-)

C'mon folks... doesn't anybody KNOW about IBM?
This had to be a MARKET DRIVEN decision, since
IBM (by their own assertion) IS MARKET DRIVEN!
The attractiveness of the smiling Countess ;-)
(dear Ada) can be only a secondary persuasion.

There's going to be a *BOOM* in Ada-based BUSINESS (i.e. $$) and
IBM's obvious intention is to be right where the action is!! 8-)

DISCLAIMER: I'm opinionated, who isn't?  
_______________________________________________________________________________

Ken Ritchie (d/b/a KCR)			Usenet:	...!uunet!netxcom!netxdev!kcr
c/o NetExpress Communications, Inc.	FAX/office:	USA (703) 749-2375

Ada Promises

[Doug Schmidt]

In article <7053@hubcap.clemson.edu>, billwolf%hazel (William Thomas Wolfe, 2847 ) writes:
>   This has been a property of some early Ada *compilers*, but is
>   not a property of the Ada *language*.  

I basically agree with this in principle, though Ganapathi and
Mendal's IEEE Computer article from February 1989 points out several
areas where the Ada's semantics of reordering operations restricts
code motion and strength reduction.  I'd assume that this penalizes
Ada on certain RISC processors since it limits the degree of
instruction scheduling possible.

>   Fortunately, compiler
>   technology is now capable of delivering tight, efficient Ada
>   object code, better than that being produced by C compilers.

Ironically, Ganapathi and Mendal conclude their article by stating
that:
 
  Use of the following Ada capabilities may hinder optimizations currently
  implemented in most Ada compilers:
  
  * exceptions
  * generic units
  * private and limited private types in package definitions
  * naming and modularity of package definitions, and
  * tasking

In other words, just about every major feature that differentiates Ada
from Modula 2 or Pascal exacts a penalty on optimization.  This is a
realistic and understandable phenomenon (C/C++ certainly contain their
share of features that disrupt optimization), but it also makes me
wonder just exactly what you mean with your claim that Ada compilers
produce better code than C compilers.

To avoid misunderstanding, can you please cite *specific* examples
(especially references to publically available literature) to support
your claim?  For example:

1. Precisely which Ada compilers produce better code than which C compilers?
   Not all compilers are created equal...

2. What are the benchmarks and where can they be obtained?  If, in
   order to generate good code, Ada programmers must limit themselves to
   a `Pascal subset' of the language exactly what advantages have
   accrued?

3. What are the hardware/OS platforms and what are the relative costs
   between the Ada and C compilers/environments?  After all, it is
   unfair to compare a $500,000 Rational Ada environment against
   a $120 copy of Turbo C on MS DOS ;-).

Without independently verifiable, empirical evidence it is difficult
to make an informed choice on this issue.  In the words of R. P.
Feynman:

  The fundamental principle of science, the definition almost, is this:
  the sole test of the validity of any idea is experiment.

Additional proof would greatly increase my confidence that Ada is more than
just another `promising' language (pun intended!).

thanks,

  Doug
--
Master Swordsman speak of humility;             | schmidt@ics.uci.edu (ARPA)
Philosophers speak of truth;                    | office: (714) 856-4034
Saints and wisemen speak of the Tao of no doubt;
The moon, sun, and sea speaks for itself. -- Hiroshi Hamada

Re: Ada compilers

[William Thomas Wolfe, 2847]

From schmidt@zola.ics.uci.edu (Doug Schmidt):
>>   Fortunately, compiler
>>   technology is now capable of delivering tight, efficient Ada
>>   object code, better than that being produced by C compilers.
> 
> 1. Precisely which Ada compilers produce better code than 
>    which C compilers? Not all compilers are created equal...

   The Telesoft TeleGen2 compiler, vs. all available C compilers,
   as of circa October 1988; contact Telesoft for details, since 
   the statement was made at the Telesoft User's Group meeting at
   the Tri-Ada '88 conference.  

> 2. What are the benchmarks and where can they be obtained?  If, in
>    order to generate good code, Ada programmers must limit themselves to
>    a `Pascal subset' of the language exactly what advantages have
>    accrued?

   I seem to recall "Dhrystone", among others, being cited.  There 
   were no limitations on the use of the Ada language.
 
> 3. What are the hardware/OS platforms and what are the relative costs
>    between the Ada and C compilers/environments?  After all, it is
>    unfair to compare a $500,000 Rational Ada environment against
>    a $120 copy of Turbo C on MS DOS ;-).

   I think the comparison might have focused on Sun workstations,
   but I'm by no means positive.  In any event, the point of contact is:

      TeleSoft, 5959 Cornerstone Court West, San Diego, CA, 92121-9891

   There were several articles in the Proceedings of Tri-Ada '88
   which considered at length the sophisticated optimization techniques
   which went into the TeleGen2 compiler; that might also be a good source. 
 
   There has been a new release of the TeleGen2 compiler since October 
   1988, and undoubtedly new releases of C compilers as well, so it 
   would probably be best to contact TeleSoft directly at the above 
   address for the most recent competitive statistics.  
    

   Bill Wolfe, wtwolfe@hubcap.clemson.edu

This has gotten stupid!

[Dick Dunn]

> > 1. Precisely which Ada compilers produce better code than 
> >    which C compilers? Not all compilers are created equal...
>    The Telesoft TeleGen2 compiler, vs. all available C compilers,
>    as of circa October 1988; contact Telesoft for details...

Oh, right, Telesoft is the unbiased judge of the universal superiority of
its own compiler!

>    the statement was made at the Telesoft User's Group meeting at
>    the Tri-Ada '88 conference.  

In other words, they made the statement in what amounts to a mutual ad-
miration society meeting.

> > 2. What are the benchmarks and where can they be obtained?...

>    I seem to recall "Dhrystone", among others, being cited.  There 
>    were no limitations on the use of the Ada language.

You "seem to recall"???  Your grandiose boasting is based on something you
don't quite remember?  Even if the one you think you remember is correct,
it's a tiny synthetic benchmark with well-known problems (acknowledged by
the author) and it is NOT suitable for comparisons of compilers.

> > 3. What are the hardware/OS platforms and...

>    I think the comparison might have focused on Sun workstations,
>    but I'm by no means positive...

But soft! 'Tis fair Amnesia come to stay a while.  Isn't it convenient how
little information there is here?  It's probably a comparison against pcc.

Bill told us that, thanks to sophisticated compiler technology, Ada
compilers can now give us better object code than C compilers.  But the
claim apparently applies only to one Ada compiler; the claim is made by
the vendor of that compiler; the claim is reported at a meeting for users
of the compiler; the benchmarks and hardware platforms used for the com-
parison are conveniently forgotten.

Pure vapor.

Bill, you argue best for Ada when you don't post.

Does anyone have any substance about code-generation quality of Ada
compilers?  I think it's a potentially interesting subject.
-- 
Dick Dunn     rcd@ico.isc.com    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...`Just say no' to mindless dogma.

Re: Ada

[Walter Rowe]

Ignore that last one ... got trigger happy ...
----------------------------------------------------------------------
>>>>> On 15 Nov 89 16:06:41 GMT, billwolf@hubcap.clemson.edu (Bill Wolfe) said:

billwolf> This is blatantly false; consider the November 1988
billwolf> article in IEEE Software ("Large Ada projects show
billwolf> productivity gains"):

billwolf> [...irrelevant text deleted...]
billwolf> on the project was counted only once.  Roughly 13 percent of
billwolf> the delivered software was reuseable.

Uhmmm ... correct me if I'm wrong here, but if a project is well
designed (ie. module specs are written to be general), I think there
would be a higher degree of re-usability for those modules, regardless
of the language used.  That's the purpose of writing generalized code.
Any good computer scientist/programmer knows that, right?

Imagine having to write sin(), cos(), etc, for every application you
needed them for.  This would of course be ludicrous, so those in the
know wrote good, generic routines to handle these functions and now
you take them for granted.

What I'm trying to say is that re-usability is not necessarily an
attribute of the programming language being used, but more likely it
is the result of using good system design techniques.  Who cares if
its C++, Ada, C, or Pascal?  If you approach the design correctly,
your solution will be general enough so as to apply to the greatest
number of variations of the same problem.  Thats what re-usability is
all about, isn't it?  Not re-inventing the wheel?

billwolf> Sounds like a continuing *success* to me ...

Sure, but so is Pascal (originally designed as a learning tool), but
its not highly used outside of Academia just like Ada is not highly
used outside of DoD.  Ever wonder why?
   
billwolf> A prime example is Unix; the current POSIX effort aims to
billwolf> standardize 1960's technology, thus resulting in a "lowest
billwolf> common denominator" which locks users into obsolescence.

I disagree.  Its not locking into obsolescence.  Its forcing one to
meet only a minimum set of requirements, which allows a maximum amount
of flexibility above and beyond those requirements.  As long as you
meet these minimum requirements, you still have the freedom to enhance
UNIX any way you see fit.  They aren't restricting you to these, but
saying that you must provide at least these things.

billwolf> Modern programming languages provide a variety of features
billwolf> to support development and maintenance of software products.
billwolf> These features include strong type checking, separate
billwolf> compilation, user-defined data types, data encapsulation,
billwolf> data abstraction, generics, flexible scope rules,
billwolf> user-defined exception handling, and concurrency mechanisms.

I have to agree with Bill on this point: more languages ARE beginning
to evolve into useful tools for productivity, rather than learning
tools, or tools intended for specific applications.  However, I think
in order to be most productive and efficient for a given application,
a language still must cater to that application to some extent (ie.
COBOL for record transaction processing, C for systems programming,
etc).

> [...] There is the August 21 89 issue of Government Computer News
> describing the problems which the huge FAA Advanced Automation
> System is having due to IBM Ada implementations and tools (or lack
> thereof).

billwolf> Are you saying that this is the fault of the *language*, or
billwolf> of IBM?

More than likely its IBM, although most of their projects seem to come
out of a committee, and in that respect, draw a striking resemblance
to Ada.  So, possibly both are at fault since Ada was designed by a
committee, too.  I think the basic point being made is that too many
hands in the pot spoil the soup, and I tend to agree with this.  Its
good to get outside opinions so that one can be as objective as
possible, but I still think that fewer people can supply a much more
rational decision.

> the programming style being promulgated by DOD for Ada [descriptive
> variable names] is anti-conducive to the stated goal of readability;  

billwolf> To C hackers, who are accustomed to single-letter variables,
billwolf> yes.  Software engineering specialists tend to have the
billwolf> opposite perspective.

Admittedly, I fall into the C hacker category, but I think Ted makes a
valid point here.  I'd much prefer to shuffle through a few pages of
documentation at the top of a print-out than have to look at unsightly
long variable/procedure/function names.  I support giving variables
meaningful names, just not unsightly long ones.

If the docs are good at the top of a file are good (ie. they clearly
and concisely convey the concept of what this code is suppposed to
do), then you shouldn't have to clutter the code with paragraph long
names.  You're trying to infer the logic being applied, not the
details of the individual statements (for alone they mean nothing
anyway).

billwolf> Bill Wolfe, wtwolfe@hubcap.clemson.edu

Walter Rowe, rowe@cme.nist.gov
---
My opinions are my own, and bare no reflection of the opinions
of the United States Government.

Re: Ada

[William Thomas Wolfe, 2847]

From rowe@cme.nist.gov (Walter Rowe):
> Sure, but so is Pascal (originally designed as a learning tool), but
> its not highly used outside of Academia just like Ada is not highly
> used outside of DoD.  Ever wonder why?

   The fact that good production-quality compilers have only been
   avaliable for the last year or two probably has a lot to do with it...

   Fortunately, as the IEEE Software article I cited demonstrates, 
   commercial use and acceptance of Ada is growing rapidly, both in 
   the US and overseas.  Non-DoD US users include General Electric, 
   Boeing Commercial Airplane, etc.; other companies, such as Arthur 
   Anderson, are considering converting to Ada now that the appropriate 
   compilers and tools are available.  Not because the DoD is using it,
   but as a simple result of business and engineering considerations. 

   Considering that the largest corporation in the WORLD, Nippon 
   Telegraph and Telephone, has maintained a committment to Ada 
   since 1982 (!!!), I'd say that Ada is certainly making excellent 
   progress in the commercial environment.  The fact that the
   DoD is requiring all its information systems work to be done
   in Ada is creating a great deal of infrastructure (e.g., the
   RAPID library of reuseable Ada information systems software
   components), which will further stimulate commercial use.  

   The experience so far has been that "once a team moved to Ada,
   they stayed with Ada.  Once Ada had been successfully used within
   a company, its use proliferated to other projects within the 
   company and to subcontractors and suppliers of that company within
   the industry."  (Ada Letters, Vol. VIII, No. 5, page 15).  Given
   that high-quality compilers have only been available for a relatively
   short period of time, and that the US Ada market was already US $1.25 
   billion as of September 1987, I think the progress so far has been 
   quite substantial.  Watch comp.lang.ada for continued updates.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada

[Pablo Fernicola]

In article <7088@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>
>   Fortunately, as the IEEE Software article I cited demonstrates, 
>   commercial use and acceptance of Ada is growing rapidly, both in 

In IEEE Software, Vol.5 Num. 3 page 26, we read

	"C++ has several advantages over Ada: ..."

>
>   The experience so far has been that "once a team moved to Ada,
>   they stayed with Ada.  Once Ada had been successfully used within
>   a company, its use proliferated to other projects within the 
>   company and to subcontractors and suppliers of that company within
>   the industry."  (Ada Letters, Vol. VIII, No. 5, page 15).  Given
		     ^^^^^^^^^^^^
		     Not a biased opinion, I hope :-)

A common syllogism nowadays is (from the same IEEE Software issue)

	Ada is good; object-oriented is good;
	therefore, Ada is object oriented.


>   Bill Wolfe, wtwolfe@hubcap.clemson.edu

BTW, it is good to hear from Bill again after the misc.jobs.misc debacle ...
--
pff@beach.cis.ufl.edu - Pablo Fernicola - Machine Intelligence Laboratory - UF
		IF YOU CARE ENOUGH TO READ SIGNATURES ...
	I am graduating next year and I am looking for a job.  
MS/BS EE, my graduate work incorporates OO-DBMS/Graphics/Robotics/AI

Re: Ada

[William Thomas Wolfe, 2847]

From pff@beach.cis.ufl.edu (Pablo Fernicola):
> In IEEE Software, Vol.5 Num. 3 page 26, we read
> 
> 	"C++ has several advantages over Ada: ..."

   But unfortunately seems to be missing fundamental features
   such as exceptions, generics, and concurrency...

> A common syllogism nowadays is (from the same IEEE Software issue)
> 
> 	Ada is good; object-oriented is good;
> 	therefore, Ada is object oriented.

   Written by the designer of C++, whose definition of object-oriented
   is "Object-oriented programming is programming using inheritance".

   The definition of "object-oriented" varies widely, but even if we
   accept this definition, we need only obtain Classic Ada (or some 
   equivalent preprocessing product) in order to use inheritance in
   an Ada environment, pending more direct support in Ada 9X.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu
 
   

Re: Ada

[Andrew Koenig]

In article <7115@hubcap.clemson.edu>, billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe, 2847 ) writes:

>    Written by the designer of C++, whose definition of object-oriented
>    is "Object-oriented programming is programming using inheritance".

Where on earth did you pick up that notion?
-- 
				--Andrew Koenig
				  ark@europa.att.com

Re: Ada

[Mats Luthman]

In article <7115@hubcap.clemson.edu>, billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe, 2847 ) writes:

>    Written by the designer of C++, whose definition of object-oriented
>    is "Object-oriented programming is programming using inheritance".

As far as I recall Bjarne Stroustrup supports the widely accepted definition
of "Object oriented language":

  A language that supports:

*  Data abstraction (encapsulation)
*  Inheritance
*  Dynamic binding

I guess that people who claim that Ada is object oriented don't agree with
this definition, at least not with the third requirement, but saying what
I cited above is (and was probably meant to be) an insult to B.S. and his
intellectual capability.

Mats Luthman

Re: Ada

[William Thomas Wolfe, 2847]

From ark@alice.UUCP (Andrew Koenig):
> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>>    Written by the designer of C++, whose definition of object-oriented
>>    is "Object-oriented programming is programming using inheritance".
> 
> Where on earth did you pick up that notion?

    From his article "What is Object-Oriented Programming", IEEE
    Software, May 1988... it's a direct quote.


    Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada

[Mats Luthman]

In article <7171@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>From ark@alice.UUCP (Andrew Koenig):
>> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>>>    Written by the designer of C++, whose definition of object-oriented
>>>    is "Object-oriented programming is programming using inheritance".
>> 
>> Where on earth did you pick up that notion?
>
>    From his article "What is Object-Oriented Programming", IEEE
>    Software, May 1988... it's a direct quote.
>
>
>    Bill Wolfe, wtwolfe@hubcap.clemson.edu


The article is 21 pages long, and is a thorough explanation of what
the author means by 'object oriented programming'. The trick of chosing
one sentence, ripped out of its context, is used again.

Mats Luthman











***

Re: Ada

[Markku Sakkinen]

In article <10171@alice.UUCP> ark@alice.UUCP (Andrew Koenig) writes:
-In article <7115@hubcap.clemson.edu>, billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe, 2847 ) writes:
-
->    Written by the designer of C++, whose definition of object-oriented
->    is "Object-oriented programming is programming using inheritance".
-
-Where on earth did you pick up that notion?

I would say that is the main theme of Stroustrup's paper from ECOOP'87
(What is "Object-Oriented Programming), a little simplified.
So, where on earth = in Paris (site of ECOOP'87) :-)
Obviously, it is hard to maintain that languages such as Ada and CLU
are not "object-oriented" in the least, unless one takes inheritance
as the single most important concept of OO.

Markku Sakkinen
Department of Computer Science
University of Jyvaskyla (a's with umlauts)
Seminaarinkatu 15
SF-40100 Jyvaskyla (umlauts again)
Finland

Re: Ada [and the object oriented metaphor]

[mjl]

In article <7115@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>   The definition of "object-oriented" varies widely, but even if we
>   accept this definition, we need only obtain Classic Ada (or some 
>   equivalent preprocessing product) in order to use inheritance in
>   an Ada environment, pending more direct support in Ada 9X.

The mind boggles: Hoare's Turing Lecture concerns about the safety of
the world have now been compounded by an order of magnitude!  I'm a
proponent of the OO approach, but this instance is all too reminiscent
of the "bag on the side of a bag" system of design so eloquently
described in Kidder's "The Soul of a New Machine." Ada is already a
tarpit of complexity.  While the natural world evolves by selection,
Ada seems destined to "evolve" by accretion.

Mike Lutz

P.S.  I'm can hardly wait for AdaLog and CommonAda, preprocessors
providing all the "benefits" of Ada as well as the logic programming
model of PROLOG and the list processing capabilities of CommonLisp.
[1/2 :-)]
Mike Lutz	Rochester Institute of Technology, Rochester NY
UUCP:		{rutgers,cornell}!rochester!rit!mjl
INTERNET:	mjlics@ultb.isc.rit.edu

Hoare, Ada, and safety/complexity

[John Goodenough]

There is a fairly widespread perception that Hoare's Turing Lecture represents
his complete opinion on Ada, as noted in a recent in article, Re: Ada [and the
object oriented metaphor] of 21 Nov 89 14:35:58 GMT mjl@prague.UUCP (Michael
Lutz):

>The mind boggles: Hoare's Turing Lecture concerns about the safety of
>the world have now been compounded by an order of magnitude!  ...

In 1987, Hoare wrote:

    ...an important goal in the design of a new programming language [is] that
    it should be an aid in specification, description, and design of programs
    as well as in the construction of reliable code.

    This was one of the main aims in the design of the language which was
    later given the name Ada.  As a result, the language incorporates many
    excellent structural features which have proved their value in many
    precursor languages such as Pascal and Pascal Plus.

    The combination of many complex features into a single language has led to
    an unfortunate delay in availability of production-quality
    implementations.  But the long wait is coming to an end, and one can now
    look forward to a rapid and widespread improvement in programming
    practice, both from those who use the language and from those who study
    its concepts and structures.

							     C. A. R. Hoare

    [in the Foreword to "Ada, Language and Methodology" by David A Watt, Brian
    A.  Wichmann, and William Findlay, Prentice-Hall, 1987.]

(Of course, the game of "proof by authority" is not all that interesting, but
if you're going to play it, ...)

John B. Goodenough					Goodenough@sei.cmu.edu
Software Engineering Institute				412-268-6391
-- 
John B. Goodenough					Goodenough@sei.cmu.edu
Software Engineering Institute				412-268-6391

Re: Hoare, Ada, and safety/complexity

[Richard Pattis]

Indeed, Tony Hoare wrote the foreword quoted (the complete foreword is about
twice as long).  Here is the context:  Hoare is a series editor for Prentice-
Hall International, and he writes a foreword for most books in the series,
including the one written by Watt, Wichmann, and Findlay.

In my reading of the foreword, it shows a masterful double meaning in every
sentence.  It looks as if Hoare is praising Ada, but he is really praising
(1) the ideas behind Ada and (2) learning about Ada (without praising using
Ada). Every sentence has a wonderful spin on it.  I advise everyone to read
this foreword skeptically; you'll surely smile a bit.

The authors are much more positive in their praise of language (I vastly
prefer teaching it, compared to Pacsal or Modula-2 in my CS-1/CS-2 classes).
But I don't think Hoare's preface can in any way be construed as being
positive towards Ada, nor as anything contrary to his Turing lecture.

Rich Pattis

Re: Ada vs. C++

[Paul S. R. Chisholm]

From pff@beach.cis.ufl.edu (Pablo Fernicola):
> In IEEE Software, Vol.5 Num. 3 page 26, we read
> 	"C++ has several advantages over Ada: ..."

In article <7115@hubcap.clemson.edu>,
billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu
(William Thomas Wolfe, 2847) writes:
>    But unfortunately seems to be missing fundamental features
>    such as exceptions, generics, and concurrency...

Exceptions:  Dr. Stroustrup just made a proposal for doing exceptions
in C++.  It looks pretty good.

Generics:  Dr. Stroustrup made a proposal sometime last year on
parametarized types.  His exception handling paper uses the same
syntax, so presumably he's reasonably comfortable with it.

Concurrency:  Most of the time, C++ programs (and programmers) should
use the facilities of the target platform.  Dr. Stroustrup has provided
support for "tasks" in both "C with classes" and C++; the AT&T C++
Language System comes with a Task class.  That's as close to standard
as C++ comes these days.  No, there's no direct support in the language
(special syntax, etc.) for supporting concurrency, for the same reason
there's no direct support for I/O:  it's better done in a library.

To summarize, C++ has the same support for exceptions and generics that
Ada has for inheritance.  (The Ada preprocessor you mention is a red
herring for DOD contractors, unless you propose they submit the
*output* of the preprocessor.)

>    Bill Wolfe, wtwolfe@hubcap.clemson.edu

Paul S. R. Chisholm, AT&T Bell Laboratories
att!pegasus!psrc, psrc@pegasus.att.com, AT&T Mail !psrchisholm
I'm not speaking for the company, I'm just speaking my mind.

Re: Ada

[Marco S Hyman]

In article <7088@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
       Non-DoD US users include General Electric, 
       Boeing Commercial Airplane, etc.; other companies, such as Arthur 
       Anderson, are considering converting to Ada now that the appropriate 
       compilers and tools are available.  Not because the DoD is using it,
       but as a simple result of business and engineering considerations. 

Large corporations such ad GE, Boeing, Arthur Anderson, etc., are not known
for state-of-the-art, pushing-the-envelope solutions to their problems.
These are the companies that buy IBM.  Ada is safe, approved by the
government, and, as I once heard Larry Rossler of the HP Language Labs
describe it, doomed to success.  Too many companies are throwing money at it
to fail.

       The experience so far has been that "once a team moved to Ada,
       they stayed with Ada.  Once Ada had been successfully used within
       a company, its use proliferated to other projects within the 
       company and to subcontractors and suppliers of that company within
       the industry."  (Ada Letters, Vol. VIII, No. 5, page 15).

I don't have any facts or figures but I suspect from my own past experience
that this is true of every successful tool/method introduced to a large
corporation.  A manager that tries something new usually goes out on a limb
and therefore works twice as hard to make it succeed.  When it does succeed
that manager makes sure all of his bosses know that he was the hero that
finally brought a software project in on time and within budget.  Since
software projects are not usually on time or within budget the new
tool/method is seen as the solution to all software woes.  Alas, it's
usually just better management plus the productivity increase that comes
with doing something new that really saved the day.

I'm not saying the new tool/method, be it Ada, C++, OOP, or whatever, does
not help.  I just wish that it wasn't seen as a panacea for all that ails
the current problems in software.  (BTW:  the current problems in software
haven't changed, IMHO, in the last 20 years -- there's just a lot more
software.) But I've changed the subject.  Sorry.

C++ and Ada are just tools, folks.  Sometimes they are the correct
tool for the job.  Sometimes they are not.

// marc
-- 
// Marco S. Hyman		{ames,pyramid,sun}!pacbell!dumbcat!marc

interesting statistic

[Dick Dunn]

Wolfe wrote:
[about Ada]
|    The fact that good production-quality compilers have only been
|    avaliable for the last year or two probably has a lot to do with it...
...and later in the same article...
|    Considering that the largest corporation in the WORLD, Nippon 
|    Telegraph and Telephone, has maintained a committment to Ada 
|    since 1982 (!!!), I'd say that Ada is certainly making excellent 
|    progress in the commercial environment...

Considering those two together, I'd say Ada's appeal must be nothing short
of amazing!  Call it two years that production-quality compilers have been
available, i.e., 1987...

I guess we can conclude that NTT maintained a commitment to Ada in spite of
a five-year lack of production-quality compilers???
-- 
Dick Dunn     rcd@ico.isc.com    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...`Just say no' to mindless dogma.

Re: interesting statistic

[William Thomas Wolfe, 2847]

From rcd@ico.isc.com (Dick Dunn):
> I guess we can conclude that NTT maintained a commitment to Ada in spite of
> a five-year lack of production-quality compilers???

    Conclusion correct... they were apparently doing MIS applications 
    in which the quality of the object code was not very important.


    Bill Wolfe, wtwolfe@hubcap.clemson.edu
 

Re: interesting statistic

[Cay Horstmann]

In article <7172@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>From rcd@ico.isc.com (Dick Dunn):
>> I guess we can conclude that NTT maintained a commitment to Ada in spite of
>> a five-year lack of production-quality compilers???
>
>    Conclusion correct... they were apparently doing MIS applications 
>    in which the quality of the object code was not very important.
>
>
>    Bill Wolfe, wtwolfe@hubcap.clemson.edu

I guess we therefore can conclude that Ada is perfectly suited for doing
MIS applications in which the quality of the object code is not very important.

If Ada has friends like Bill, does it need enemies?  :-)

Cay
> 

Re: interesting statistic

[William Thomas Wolfe, 2847]

From horstman@sjsumcs.sjsu.edu (Cay Horstmann):
>>> I guess we can conclude that NTT maintained a commitment to Ada in spite of
>>> a five-year lack of production-quality compilers???
>>
>>    Conclusion correct... they were apparently doing MIS applications 
>>    in which the quality of the object code was not very important.
% 
% I guess we therefore can conclude that Ada is perfectly suited for doing
% MIS applications in which the quality of the object code is not very 
% important.

    Quite correct.  Now that production-quality compilers are widely
    available, it is also perfectly suited for an extremely wide range
    of applications, and is being used accordingly.


    Bill Wolfe, wtwolfe@hubcap.clemson.edu

Ada allows one-char names (was Re: Ada)

[Steve Frysinger of Blue Feather Farm]

From article <ROWE.89Nov16140835@stella.cme.nist.gov>, by rowe@cme.nist.gov (Walter Rowe):
> billwolf> To C hackers, who are accustomed to single-letter variables,
 
> long variable/procedure/function names.  I support giving variables
> meaningful names, just not unsightly long ones.

I've been enjoying this debate, but for the sake of clarification I must
point out that Ada permits one-character variable names, and that most
C compilers I know allow variable names as long as Ada allows.  So I
submit that variable name length is irrelevant to this discussion.

Just wanted to keep folks who don't know Ada (or C) from misunderstanding!

Steve Frysinger

Forward into the past

[Dick Dunn]

billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu (William Thomas Wolfe,
2847 ) writes about UNIX and the Ada<->UNIX conflict that Ted Holden had
commented on:

>    A prime example is Unix; the current POSIX effort aims to 
>    standardize 1960's technology, thus resulting in a "lowest
>    common denominator" which locks users into obsolescence.

I picked this out of the latter half of an article where Bill was objec-
ting to Ted saying things that were "blatantly false" (Bill's words).  Bill
ought to be a little more careful about his own blatant falsehoods.

The POSIX work does, in fact, standardize some things which existed in the
'60's.  But it also covers mechanisms introduced in the '70's (e.g., job
control) and even into the latter part of the '80's (such as the "session"
mechanism).  Wouldn't it be rather disturbing to have a standard which
*excluded* technology older than 1970?!?

Standards are developed in two ways--either they codify existing practice,
or they attempt to constrain future practice.  Most standards in computing
are of the former sort.  The danger of a "codification" standard is, as
Bill obliquely points out, that it doesn't provide any guidance for the
future.  However, it does NOT lock people in; they are free to experiment
with extensions to this type of standard.  As new practice emerges beyond
the old standard, a basis for a successor standard is built.  Defining a
standard _a_priori_ without the benefit of existing practice is much harder
to get right.  You have to use the best research available to you, and hope
it's right.  It's sometimes necessary; sometimes an industry can't hope to
move forward without a standard.  (Consider TV, CDs, etc.)  Ada is in this
second class of standardization (unlike almost all other programming
languages).  It would help a lot if people who advocate either approach to
standardization would be less parochial and realize the tradeoffs.

>    Ada's problem with Unix is that Unix, being 1960's technology,...

Careful there!  People who live in glass houses...

To the extent that UNIX is 1960's technology, Ada is 1950's technology
and UNIX is the more modern of the two by a decade!  I'm serious...the
basic control structures, not to mention the "look and feel" of algorithmic
languages, was pinned down by the end of the 50's; it took another two years
to get it canonized in Algol 60 (with the "real" report out in '62).  Sure,
if I'm going to characterize Ada as a "'50's language" I have to ignore a
lot of important characteristics--but no more than are ignored by charac-
terizing UNIX as "1960's technology".

>    [UNIX] does not properly support lightweight processes...Modernized 
>    versions of Unix (e.g., MACH) which are designed to provide
>    such support remove the difficulty...

Bill is one of the people who has been arguing (over in comp.software-eng)
against the value of having a heavy operating systems course in a CS
curriculum...yet here we find that he thinks Mach is a "modernized version
of UNIX"???  I've seen trade rags muddle it that way, but it's wrong...
UNIX and Mach are not even the same type of animal.  But the more signifi-
cant misunderstanding is the idea that somehow lightweight processes should
have been in UNIX long ago.

The reason we have only recently seen a more widespread implementation of
lightweight processes is that it's only recently (meaning within the last
few years) become reasonably well understood just what the abstraction of a
"lightweight process" should be.  The understanding has been evolving along
with various experiments in hardware parallelism of various granularity.
The problem was not a matter of finding a workable abstraction, but of
choosing the right one(s).  The approach, in the UNIX community in
particular, is to try things first in research work, then let them gain
some wider experience in the more avant-garde places in industry, bring
them into the mainstream, and finally standardize them.  This cannot help
but look strange in the Ada world where standardization comes first and is
followed by trial.
-- 
Dick Dunn     rcd@ico.isc.com    uucp: {ncar,nbires}!ico!rcd     (303)449-2870
   ...`Just say no' to mindless dogma.

Re: Ada vs. Posix -- the battle continues

[mjl]

In article <7053@hubcap.clemson.edu> billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu writes:
>> In particular, the
>> ordinary systems which most people will be seeing in front of them for the
>> next 5 - 15 years, UNIX systems and PCs, will not run Ada accepteably.
>
>
>   A prime example is Unix; the current POSIX effort aims to 
>   standardize 1960's technology, thus resulting in a "lowest
>   common denominator" which locks users into obsolescence.

Actually, both Unix and Ada are products of the 1970's.  The difference
is that Unix, being primarily of commercial interest, has been able to
evolve, whereas Ada, a government sponsored thing-a-ma-bob, has
stagnated.  It's a shrine to the ideas of 1975, both good and bad.  The
fact that Unix has evolved in ways incompatible with Ada says as at
least as much about Ada as it does about Unix.

I followed the development of Ada from its inception as Strawman, and
became increasingly more depressed as the work proceeded.  The good
concepts Ada embodies are overwhelmed by its complexity (see Hoare's
excellent discussion of this in his Turing Lecture -- all of his
comments still apply).

Ada is the PL/I of the 70's, unusable until the mid-80's; is it destined
to be the choke-collar of DoD software development in the 90's?

Mike Lutz
Mike Lutz	Rochester Institute of Technology, Rochester NY
UUCP:		{rutgers,cornell}!rochester!rit!mjl
INTERNET:	mjlics@ultb.isc.rit.edu

Re: Ada & Posix

[William Thomas Wolfe, 2847]

From mjl@cs.rit.edu:
> Actually, both Unix and Ada are products of the 1970's.  The difference
> is that Unix, being primarily of commercial interest, has been able to
> evolve, 

   Thus generating the need for the POSIX effort.  Ada, on the 
   other hand, standardized itself to start with.  Furthermore, 
   its definition was frozen for ten years precisely in order to
   provide vendors with the ability to amortize their investments
   over that period of time.  Ada has always had its portability,
   whereas Unix is just now struggling to achieve it.

   Now that Unix is finally standardizing, work is also in progress
   (in the IEEE 1003.5 committee) to develop a standardized Ada binding
   to the IEEE 1003.1 POSIX standard.  From AlsyNews, September 1989:

      Ada applications will have a major portability advantage
      over C applications because Ada's strong typing will assure
      that an application accesses only the services that are in
      the POSIX packages.  A C application might inadvertently mix
      portable POSIX services with non-portable services provided
      by the local operating system.

   A full IEEE ballot on the Ada binding to POSIX is expected by year-end.


   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: Ada & Posix

[William Thomas Wolfe, 2847]

From billwolf%hazel.cs.clemson.edu@hubcap.clemson.edu:
>    Ada has always had its portability,
>    whereas Unix is just now struggling to achieve it.

   Consider also this quote from last Wednesday's Wall Street Journal:

      Currently, about 9% of the world's computers run Unix.
      It was feared that the computer industry's inability to
      agree on a single version of Unix would slow its spread.
      But because there is now a potential standard version of
      Unix, the operating system's popularity is expected to
      surge.  Analysts estimate that more than a quarter of the
      computer systems will run Unix by 1993.  "Having a clear
      common [standard] will encourage the perception that Unix
      is a mainstream product," said Eric Schmidt, vice president 
      of Sun Microsystems Inc.'s general systems group.

   Contrary to what some Usenetters seem to think, Unix is by no
   means universal; it is only recently discovering the need to
   impose the discipline of standardization, so that it might seek 
   more than its present single-digit level of market share.
 

   Bill Wolfe, wtwolfe@hubcap.clemson.edu

Re: A farewell to Ada

[Richard S D'Ippolito]

Painful as it was, I read your whole article, Ted.


When you say (in article <14033@grebyn.com>, Ted Holden):

>     Does Ada work any better for large scale systems?  Another article
>in the same Journal of Electronics Defense issue describing use of Ada on
>the 1,246,000 line Army AFATDS system claims that:
> 
>      "Ninety percent of the software requirements were met with no major
>      software problems."
> 
>as if this were good.  The man is claiming that he had major language-
>related problems with 124,600 lines of code out of 1,246,000.

how can you expect to be taken seriously?  Do you really believe the math
and premises behind your statement?  Wow!


Rich
-- 
We use kill ratios to measure how the war is going.
We use SLOC ratios to measure how our software is coming.
(Idea from Gary Seath)                                        rsd@sei.cmu.edu
-----------------------------------------------------------------------------

Re: A farewell to Ada

[Michael Schwartz]

OK.  You win. I have to put in my 2 cents' worth.  It's hard, because I
agree with many things that everybody has said.

Ada has been getting a bum rap.  Ada was not designed by committee, it
was designed by competition.  C, on the other hand, has been judged by
its applications.

Ada had no substantial applications to benchmark its design against.
The software engineering requirements imposed on Ada were for
programming in the large.  Precisely what Ada has been shown to be good
at.  Not surprisingly, Ada has not been found perfect for every
application area.  Where it has failed, Ada-9X proposals have been
submitted to change it.

C was developed for systems programming.  The worth of a compiler was
judged by the ability to build a good, modular, maintainable operating
system.  Where C failed, the language was changed.  And changed.  And
changed.

It has surprised no one that C is more responsive to change requests
than Ada.  Nor is it surprising that inexperienced software engineers
write better code in Ada than in C.  It has not escaped anyone's
attention that there are more inexperienced software engineers than
experienced software engineers.

Sorry for belaboring the obvious, but let's start somewhere.  Now let's
talk about Ada and Unix.  

Areas where Ada and Unix have problems:  a) System-dependent features
accessed from Ada b) Scheduler conflicts--Ada tasks vs Unix tasks c)
Ada image sizes and startup times

Of these areas, (c) is the most readily addressed.  I have heard a
number of Ada 9X proposals amounting to a mechanism to freeze the Ada
image after elaboration, but before execution.  So much for startup
times.  I have also heard several vendors tout smarter link-editors
which will help resolve image size problems.  I also hold hope for
shared library implementations; the Ada runtime can be shared among all
processes needing it.

Area (a) is one that requires Ada vendor support.  It is difficult to
think of a non-trivial software system without some system-dependent
feature.  After all, we buy different hardware precisely because of
these features.  In my mind, a major difference between a good Ada
compiler and a marginal one can be found in the support for operating
system signals, pragma interfaces, and representation specifications.
It is no anathema to me to have an Ada system contain bodies which are
Pragma Interface (C,...) EVEN IF I DON'T HAVE TO.  Maintenance costs
must be kept foremost.  Reducing maintenance costs is, after all, one
of the major considerations in developing Ada.  Let's not spoil this by
insisting that every Unix guru learn Ada.

Scheduler conflicts (b) remain a problem because Unix processes are not
the same as Ada tasks.  Several have pointed out that Ada tasks are
'lightweight'; they mean that Ada tasks are represented by different
execution threads (instruction pointers and stack frames) but the same
data space.  At least one Unix vendor has implemented a lightweight
process type in the Unix kernel.  It is possible that a good solution
will be to build an Ada compiler which maps its tasks to lightweight
Unix processes, letting the Ada scheduler be either eliminated or
vastly reduced.

In the absence of this solution, a multi-tasking Ada program must build
a monitor to mediate all operating system calls which may 'use up' its
most vital resource -- the Unix operating system process.  The
efficiency with which this may be done is directly related to both the
Ada compilation system's (ACS) ability to interface with Unix (see
(a)), and the 'goodness' of the Unix in question.

Since 'signals' are to Unix more or less what 'rendezvous' are to Ada,
the more events which can be propogated to the Ada monitor from Unix
via signals, the more efficient the implementation.  Broad support for
SIGIO seems to particularly help.

With current compiler technology, one published result we have obtained
is multi-tasking access through sockets within 20% of the performance
of a C program using standard fork() and exec() calls.  Both
applications were able to exchange over 5000 tcp/ip messages per
second with a cheap 68020 box.  Turning off the time-sliced tasking in
the Ada program helped significantly.

One other result is that using our Ada abstraction, new employees were
able to contribute to our project within one to two days, even with no
prior Unix experience.  Of course, a C abstraction is possible--but why
doesn't anyone use one?

A 'today' note: Dennis Ritchie spoke to the FRUUG (Front Range Unix
Users Group) last night about 9th Edition IPC.  He has developed a
different IPC abstraction for his research.  In syntax, it is similar
to our Ada (and C) abstractions.  Of course, it has kernel support :-).

There.  I feel better now ('thar she blows!)

Michael
-----------------------
schwartz@pogo.den.mmc.com  "Expect everything ... 
mschwartz@mmc.com                   and the unexpected never happens." 
ncar!dinl!schwartz                               --the phantom tollbooth

DISCLAIMER:  The opinions expressesed are not necessarily those of my 
	     employer or myself.

-- 
-----------------------
schwartz@pogo.den.mmc.com "Expect everything ... 
mschwartz@mmc.com                   and the unexpected never happens." 
ncar!dinl!schwartz                               --the phantom tollbooth

DISCLAIMER:  The opinions expressesed are not necessarily those of my 
	     employer or myself.