friedl@vsi.UUCP (Stephen J. Friedl) (05/13/88)
Hi net.{guys,gals},
A number of months ago I became exposed to the Yourdon
Structured Analysis methodology (DeMarco's book) and was very
impressed with it. I had previously done systems (20k-50k lines)
with no more than good programming skills, and the *design* skills that
I learned were really helpful.
At any rate, I am very naive in this area, having only seen
one Way of Doing Things and also for not having done large
systems. I have a general kind of interest in exposing myself
to another Way of Doing Things and have one in mind.
The Byte Book Club main selection for this month is
_SADT: Structured Analysis and Design Technique_ by David A.
Marca and Clement L. McGowan ("with a forward by Douglas T.
Ross").
(A) How is SADT?
(B) How is this particular book?
(C) If one wanted to be exposed to a couple of ways
of doing SA, what is a good second choice?
Thanks folks,
Steve
--
Steve Friedl V-Systems, Inc. (714) 545-6442 3B2-kind-of-guy
friedl@vsi.com {backbones}!vsi.com!friedl attmail!vsi!friedlroot@ahe3b1.UUCP (Root) (05/15/88)
From article <660@vsi.UUCP>, by friedl@vsi.UUCP (Stephen J. Friedl): > SADT: Structured Analysis and Design Technique by David A. > Marca and Clement L. McGowan ("with a forward by Douglas T. > Ross"). > > (A) How is SADT? > (B) How is this particular book? > (C) If one wanted to be exposed to a couple of ways > of doing SA, what is a good second choice? > From my reading of the book, SADT is an extremely powerful system modeling technique with potential way beyond software engineering. In fact, it appears to have gotten more use in organizational analysis and design than anywhere else (E.G. job design and control). The basic conceptual unit (the SA box) : | | CONTROL V ----------------- | | INPUT ------> | (subject) | ---> OUTPUT | | ----------------- ^ | MECHANISM can be combined and/or successively decomposed to model virtually any task. The running example in the book is an analysis of a Tool Shop. Example subjects: Pick Tools, Setup Machining Place, Evaluate Job Progress. Example control flows: Blueprints, Job Completion requests, Job order steps. Example Outputs/Inputs: Unfinished Parts, Tool Crib, etc. The book is an extremely detailed 'step-by-step' cookbook which includes a great deal of information about how to manage and organize the products (including standards,etc.) of an SADT analysis (Each set of SA box diagrams is called a KIT, the construction of a KIT is called an AUTHOR/READER cycle). The latter half of the book gives example KITS from 4 application areas. The technique is of course copyrighted and sold by a Mass. company called SofTech. The most frustrating aspect of the book to me was the enigmatic claim in the preface by the technique's inventor: 'There are two main styles of SA modeling: activity models stress the happenings of the system; data models stress the things of a system. Both use the same box-and-arrow graphic language, in dual ways (the roles of boxes and arrows interchange)'. That unfortunately was the last reference to data modeling; the rest of the book concentrates exclusively on activity modelling. I have absolutely no doubt that a properly executed SADT would serve as a superb basis for a software construction project. It would take a long time and it would highlight the context within which the system would be expected to operate, but it might raise very sticky questions about the functioning of the organizational unit being modeled. (i.e. make sure that a corporate sponser is prepared to question the operation of the WHOLE unit, not just the 'computerized' part of it). As the authors present the method, I have doubts about its utility/cost ratio. But as a structured technique for requirements analysis or 'getting a feel for the problem' it makes a useful addition to the armamentorium of the individual system analyst/designer. Don Schopflocher Alberta Hospital Edmonton Psychiatric Treatment Center 'Yes and I must be nuts to be in this business'
mcgrath@kodak.UUCP (bill mcgrath) (05/16/88)
high level, abstract definition of enterprises which are supported by systems. It is used by DOD in its Integrated Computer Aided Manufacturing (ICAM) process to represent system development capabilities of vendors and configuration control and management abilities. Yourdon is a systems development methodology with diferent and more rigororous rules with the goal of building a system. The goal of SADT is to gain an understanding of an enterprise and document it. It will break down in doing detail design. All of this is arguable. Most system design methods are extensions of Yourdon not SADT. Yourdon rules and procedures constrain thinking around high level definition of an enterprise. Read 'Diagramming Techniques for Analysts and Programmers' by Martin and McClure, Prentice-Hall. There are others. Bill McGrath
mcgrath@kodak.UUCP (bill mcgrath) (05/16/88)
In article <660@vsi.UUCP> friedl@vsi.UUCP (Stephen J. Friedl) writes: >Hi net.{guys,gals}, > > A number of months ago I became exposed to the Yourdon >Structured Analysis methodology (DeMarco's book) and was very >impressed with it. I had previously done systems (20k-50k lines) >with no more than good programming skills, and the *design* skills that >I learned were really helpful ADT is a methodology with rules and procedures to analyze and present high level, abstract definition of enterprises which are supported by systems. It is used by DOD in its Integrated Computer Aided Manufacturing (ICAM) process to represent system development capabilities of vendors and configuration control and management abilities. Yourdon is a systems development methodology with diferent and more rigororous rules with the goal of building a system. The goal of SADT is to gain an understanding of an enterprise and document it. It will break down in doing detail design. All of this is arguable. Most system design methods are extensions of Yourdon not SADT. Yourdon rules and procedures constrain thinking around high level definition of an enterprise. Read 'Diagramming Techniques for Analysts and Programmers' by Martin and McClure, Prentice-Hall. There are others. Bill McGrath
rockmore (A. Joseph Rockmore) (05/26/88)
there are a couple of products available that implement sadt (actually idef). i have no direct experience with any, but for one who is interested in using idef they are worth looking into. in particular, check out meta software's design/idef tool (617/576-6920)...seems to be what one would want. bye the way, we used idef for *documentation* on a large multi-developer software project (written in lisp and fortran!) and found it adequate. we tried to use it as a design tool and found it woefully lacking. ...joe