EBERARD@ADA20.ISI.EDU (Edward V. Berard) (05/03/87)
Recently, an instructor at one of the military academies told me how
she had selected a book for an introductory Ada class. She had
rejected Booch's book (Software Engineering With Ada) in favor of
another text. It was not so much the text she had selected that
bothered me, as it was her reason for rejecting Booch's book. "Booch
takes too long to get to any code.", she said, "I want to see
something like 'Hello World' real quick." [For those of you who have
never programmed in C, or, more precisely, read Kernighan and
Ritchie's book on the C programming language, the "Hello World"
program is the first C program covered in many introductory C
courses.]
Kernighan and Ritchie (K&R) and Booch represent two very different
views on teaching programming. K&R stresses the age old thinking which
says that students of software must see, write, and execute code
before anything else will be meaningful. Booch, on the other hand,
stresses that students should know what they are doing before they
attempt to write code. The K&R approach has its roots in software
antiquity.
Programming code is the "cocaine" of the software world. To many
programmers and managers it is all that matters. While software is
being designed, managers wait nervously and the programmers/coders
wait impatiently. One the design document is finished, the "real work"
can begin. With any luck the code which is produced may closely
resemble what is described in the design documentation.
To an outsider this infatuation with code seems strange. One hears
from many sources that coding usually takes up only 10 to 15 percent
of the software life-cycle. Why then do we focus so much attention on
the syntax and semantics of the programming language? Several reasons
come to mind:
1) Many of those who are already programmers and instructors
believe strongly that, only if one is intimately familiar with
code, can one fully understand the implications of any other
part of the software life-cycle.
2) Some in the Ada community feel that the software engineering
embodied in the Ada language will either be obvious to the
neophytes or that through constant use of the Ada language, good
software engineering concepts will be absorbed "via osmosis."
3) The concept of "instant gratification" is very much entrenched
in modern software production. Sitting at their terminals in
their offices or cubicles, programmers very much resemble "rats
in Skinner boxes" who continually press a lever (the RETURN key)
for constant reenforcement of their behavior. We are only now
beginning to see tools which will allow us to "execute a design."
4) Software people have little faith in those concepts that come
before the coding phase. "How can anyone possibly describe
something which is not yet coded?", they reason. There is little
emphasis on non-coding tasks in most commonly available
training.
It seems that most people have not understood the intentions of the
U.S. Department of Defense (DoD) regarding the Ada effort. It is
better engineered software that is desired, not merely "FORTRAN
rewritten using the syntax and semantics of the Ada language." Too
much emphasis has been placed on a tool (Ada) and not on the task
(better software).
Learning the details of the Ada language is at the "noise level" of
most software projects. In fact, only a very small part of any "Ada
education effort" needs to focus on the language itself. Concepts like
configuration management, software design methodologies, data
abstraction, concurrency, software testing, and project management
must be an important part of any Ada training effort.
Of course, there are many problems which must be solved, for example:
- Contracting offices and project managers must recognize that the
least significant part of any Ada training effort is the
learning of the syntax and semantics of the language. Yes, it is
important for programmers to learn the Ada language, but this is
a trivial task compared to learning about modern software
engineering.
- Many of those who "teach" the Ada language are unfamiliar with
the bulk of modern software engineering. For example, most may
only have familiarity with functional decomposition approaches
to software development. Few can name any references on software
quality assurance. A surprising number cannot cite any studies
which correlate coding style with debugging and testing
efficiency.
- When software engineering concepts are introduced into an Ada
curriculum, it is often introduced in a very "watered down"
form. This is so that those least prepared to develop quality
software can maintain their positions -- managers *and*
programmers.
- There is still a widely-held belief that all that is involved
with transitioning to Ada technology is a change of programming
language. In reality, software development and maintenance
practices will have to change, in-house and government software
standards will be impacted, and business practices will change.
[It is often those in the commercial sector who pick this up
more readily than those in the defense sector. Further, those
doing business applications using Ada technology more quickly
see the impact of Ada technology than those doing scientific and
engineering applications.]
I would recommend that those charged with procuring Ada training, and
those who determine the Ada qualifications of a potential contractor,
look beyond mere coding ability. We must recognize that probably the
greatest effort facing the advocates of Ada technology will be
reformation of "code junkies."
-- Ed Berard
(301) 695-6960
-------cabo@tub.UUCP (05/06/87)
In an otherwise very reasonable article in comp.lang.ada,
ucbvax!EBERARD (probably wrong address) writes:
() [...] K&R stresses the age old thinking which
() says that students of software must see, write, and execute code
() before anything else will be meaningful. Booch, on the other hand,
() stresses that students should know what they are doing before they
() attempt to write code. The K&R approach has its roots in software
() antiquity.
K&R is a book about a programming language (a good one at that, by the way).
Grady Booch's book is a book about software design in a programming language.
These are two entirely separate subjects. You can learn software engineering
methods without learning the syntax of the Ada language at the same time,
and you can learn programming in C without simultaneously learning software
engineering methods.
A book that both teaches software engineering and a programming language
seems to assume that the intended audience still needs to learn both subjects.
Probably a reasonable assumption for many people who are now learning Ada.
Even more so in that Ada does have a few fine points that only can be
unleashed in conjunction with knowledge about software engineering.
For the C language novice in 1978 (when K&R was written), such an assumption
would have been invalid; I would have been bored if K&R had placed more
emphasis on the methods I already had been comfortable with in languages like
Simula etc. that I had used before. Its successor, the book about the C++
language (Bjarne Stroustrup 1986) still assumes some basic knowledge about
software engineering when giving rules of thumb for the use of C++.
The Ada Reference Manual (which is comparable to the reference sections
of both K&R and BS) also does not give any guidelines for design and
testing methods (and we all agree it should not do that), but if you
know anything about design you immediately understand what packages and
all these Ada concepts are about, although these are complex enough that
a good text will help you use the right concept at the right time.
For the software engineering novice (as opposed to the C language
novice that K&R addresses), it is an interesting issue (e.g. see
comp.edu) whether some early experience in simple programming helps
understand software engineering concepts later or just helps people to
start programming without design.
For university education, I still prefer first to learn to put letters
on paper (i.e. programming) before learning to write entire books (i.e.
software design). However, just being able to put letters on paper
does not make you a writer (i.e. just being able to program does not
make you a programmer).
--
Carsten Bormann, <cabo@tub.UUCP> <cabo@db0tui6.BITNET> <cabo@tub.BITNET>
Communications and Operating Systems Research Group
Technical University of Berlin (West, of course...)
"Das Problem ist nicht, wie man den Ansturm neuer Tendenzen aufhaelt,
sondern, wie man die rechten Loesungen dafuer findet" -- Walter Gropiusrcd@ico.UUCP (Dick Dunn) (05/13/87)
In one part of a rather lengthy article, Edward Berard takes on Kernighan & Ritchie's _The_C_Programming_Language_. He was talking about an introductory text, so I'm not sure why he's picking on K&R, but he compares their book with Booch: > Kernighan and Ritchie (K&R) and Booch represent two very different > views on teaching programming. K&R stresses the age old thinking which > says that students of software must see, write, and execute code > before anything else will be meaningful. This is nothing more than an unthinking cheap attack on K&R. It would seem that Mr. Berard believes that K&R intends to teach programming simply because he thinks it ought to do so. However, if one manages to read as far as the fourth paragraph of the Preface, one finds: "This book is not an introductory programming manual; it assumes some familiarity with basic programming concepts..." Perhaps this was overlooked--after all, the Preface of a book may not be good reading (unless you want to know the purpose of the book:-), so let's have a look at the beginning of the "real" text. If we read as far as page 1 of "Chapter 0" we find the following terms used without prior definition: programming language, operating system, text-processing, data-base, characters, character strings, addresses, storage allocation, heap, garbage collection, file-access methods, single-thread control flow, coroutines I cannot, in my wildest dreams, imagine a normal neophyte being able to read this section...hell; he won't even be able to parse some of the sentences. It is not the case that K&R present the "programming first, thinking later" approach. They have set out to provide a ready introduction and reference for a particular programming language, and have succeeded in doing so. K&R have been set up. "We want an introductory text. We will label them an introductory text. Then we will demonstrate that they have failed." [Hey, look, the shop manual for my car doesn't provide spiritual guidance either.] A somewhat worse confusion over teaching "programming" (I would rather a less loaded term implying "the complete process of constructing functioning software") immediately follows in Berard's article: >...Booch, on the other hand, > stresses that students should know what they are doing before they > attempt to write code... The reality of teaching lies in between the code-first approach (mis- attributed to K&R, but it does exist elsewhere) and an approach which holds off the code until the concepts are ingrained...because the fact of the matter is that very few students can hang on to a substantial abstract framework without something concrete to which they can relate it. This is easy to observe in engineering and physical science undergraduate curricula. In the first year the students will be taking (let us say) calculus and some substantial classical physics which requires calculus. If the calculus courses follow a purely mathematical development of functions, series, limits, etc. without adequate illustration of the application of the concepts, the math instructors find that their students are learning calculus better--and faster--in their physics courses. (There are, of course, areas where it's hard to find the concrete materi- al--for example, some concepts in topology--but the production of software is not such an area.) I'm not going to argue that the coding should come first. That's not what I'm saying and it's not even in the back of my mind. It would be silly to teach that way...but it's equally silly to think that you can (let alone should) teach the concepts first and the programming later. That's as absurd (and antiquated) as the "waterfall model" of software lifecycle. Consider it an overreaction to the "code first" approach. It's all too simple: Teach the two together. Start developing the idea of a programming language and a programming environment as you develop the first concepts. By the time you've got enough concepts to think about interesting problems, you've also got enough concrete information to show what an actual solution to a simple problem might look like. And, I know it's heresy in this group where so many people think that there is One True Language, but you can use a couple of different programming languages to illustrate examples--if you're careful, that can prevent students getting hung up on one language. (This is somewhat how I was first taught. Perhaps the two languages were not the best choices--FORTRAN and BASIC--but hey, that was twenty-odd years ago, and it worked then.) Another way to look at what I'm saying: overemphasizing the coding is bad; ignoring it is just as bad. A little more from Berard's article: > Programming code is the "cocaine" of the software world. To many > programmers and managers it is all that matters... Replace "cocaine" with "currency". To many clients in the commercial world, the code is [almost!] all that matters, because they aren't interested in plans and studies except insofar as they help produce the end result, and they don't believe that they can sell specs-by-the-pound. The methodology is not the end product. >...While software is > being designed, managers wait nervously and the programmers/coders > wait impatiently... So get some good managers! Sheeeesh! As for the programmers/coders: If you divide your world into "those who design" and "those who implement the design" you have created a caste system. You have a social problem and you cannot solve it by waving methodology about. >...To an outsider this infatuation with code seems strange. One hears > from many sources that coding usually takes up only 10 to 15 percent > of the software life-cycle... This is a favorite litany of the methodology mavens...but if you think about it, it's only reasonable. Why is coding only 10-15%? Well, one set of reasons is that the code produced is so often late, inefficient, not robust, inscrutable, unadaptable, and nonportable. We spend the bulk of our time screwing around with code that's already written because it was lousy code in the first place...somehow I don't buy the idea that the solution is to improve our ability to screw around with the code! Couldn't we try just a little to reduce the need to screw around with it? If we had done a good job with the 10-15% of the work, a lot of the 85-90% remaining wouldn't have been necessary. A couple more comments from Berard: > 4) Software people have little faith in those concepts that come > before the coding phase. "How can anyone possibly describe > something which is not yet coded?", they reason... Rubbish. These aren't software people. > It seems that most people have not understood the intentions of the > U.S. Department of Defense (DoD) regarding the Ada effort. It is > better engineered software that is desired, not merely "FORTRAN > rewritten using the syntax and semantics of the Ada language." Too > much emphasis has been placed on a tool (Ada) and not on the task > (better software). I agree with this in a perverse sense: I do not understand it to be the intent of DoD to produce better engineered software instead of a new language. If that is what they desired, why did the requirements used in Ada development (the *man sequence) specify nitty details of syntax and semantics instead of focusing on requirements? Why did they spend a decade screwing around with a programming language before getting on to the environment? Berard is quite right that "too much emphasis has been placed on a tool...and not on the task..." - and the nature of the development of Ada is the best example of that misplaced emphasis. -- Dick Dunn {hao,nbires,cbosgd}!ico!rcd (NOT CSNET!) (303)449-2870 ...Nothing left to do but smile, smile, smile.
4526P@NAVPGS.BITNET ("LT Scott A. Norton, USN") (05/15/87)
In <1061@ico.UUCP>, hao!ico!rcd@ames.arpa (Dick Dunn) remarked, "A somewhat worse confusion over teaching 'programming' (I would rather a less loaded term implying 'the complete process of constructing functioning software') immediately follows in Berard's article:" I think the term he wants is "software engineering." The hard part about teaching software engineering is that the need for good engineering is not apparent at the classroom level. The programs that are written by individuals in an undergraduate software course are less than a thousand lines. They can be fully understood by one person. They do not undergo maintenance, and do not have to adapt to changes in the environment, new hardware, or changed specifications. They usually do not need to be robust, since they are not used by many different users or under tight constraints. There is certainly a skill called "Programming." Selecting algorithms and data structures, making loops start and stop in the right places, avoiding deadlocks; they are all part of programming. But, when you move to programs of over one million lines, the problems you face are different. Consistancy of the specification becomes more difficult. Testing and debugging become more difficult ( some people say impossible ) Training new staff is necessary as the work progresses. As people leave the project, the knowledge they have must be passed down to the remaining staff. Its not a difference in scale, its a difference in kind. If you teach a course in programming, you expect people to come out of it knowing how to write code. Give them clear specifications and they should be able to write modules that will meet the specs. But writing the specs, making the design decisions that determine the specs, managing the programmers, designing tests, chasing down the requirements that the system must meet, developing the documentation, training the staff ( not how to code, but what the project is supposed to do ) are part of the larger world of software engineering. Its a different dicipline, and can't be taught in a single course. Ada is supposed to be a language that makes it easier to match modules to specs, design tests, eliminate some tacit assumptions about interfaces, and make code more readable to ease the problems of bringing new people into a project or of doing maintenance. Ada will be successful if it improves not only coding, with its 15% of the load, but also these other areas. Programming : Software Engineering :: Word Processing : Writing a novel When I was in fourth grade, I thought that higher math was being able to do, like, really big long division problems. LT Scott A. Norton, USN Naval Postgraduate School Monterey, CA 93943-5018 4526P@NavPGS.BITNET