QUESTIONS AND ANSWERS: The dMILL All-Networks Productivity Kit for Clipper


QUESTION: Isn't Clipper a multiple-user product right out of the box?  ANSWER:
The single-user features in Clipper 5.2 are very strong, but the multiple-user
features are very weak.  To make the multiple-user features of Clipper as
strong as the single-user features, the dMILL All-Networks Productivity Kit
for Clipper (with the Clipper 5.2 option) provides 6,000 lines of Clipper 5.2
code and almost as much documentation as Clipper itself (the equivalent of
1,000 pages in manuals of the size of the Clipper manuals).


QUESTION: Isn't the dMILL All-Networks Productivity Kit for Clipper another
NetLib clone?  ANSWER: NO!!!  NetLib is a vertical product which gives access
to features of the network operating systems Novell, NetBIOS, and Vines.  The
Kit is a horizontal product which supports development for all DOS-based
networks.  It is an infrastructure product designed to improve the
productivity of all parties concerned with multiple-user development, from
programmers to managers to end-users.


QUESTION: OK, so how would a programmer decide which one to get?  ANSWER:
Since the Kit helps you solve all of your network-independent problems, you
should buy the Kit before you buy any vertical, network-dependent product such
as NetLib.  If your Clipper programs will need direct access to the services
of a particular network operating system - and using the RUN command to
execute command-line utilities won't give enough access - you will also need a
product like NetLib.

   ALL multiple-user programmers need the Kit and SOME multiple-user
   programmers need NetLib.


QUESTION: If I buy the Kit, do I also need the dMILL Network Course for
Clipper or the Professional Option?  ANSWER: The Course is part of the Kit.
You can buy the Course separately but you cannot buy the Kit without the
Course.

   The Kit contains a Summer '87 source code library.  The Professional Option
for Clipper 5.01 is a Clipper 5.01 version of this library.  The Professional
Option for Clipper 5.2 is a Clipper 5.2 version of this library.  Clipper 5
programmers can use the Summer '87 library, but the Professional Option uses
Clipper 5 features to encapsulate the library code and data.  Clipper 5
programmers already know about the advantages of encapsulation, a method which
is so powerful that Summer '87 programmers are advised to upgrade to Clipper 5
to gain its benefits!

   The Clipper 5.2 library fully supports RDDs and multiple-record locking.


QUESTION: I have enhanced LOCKS.PRG which comes with Clipper.  Does the Kit
really offer that much more over my enhanced LOCKS.PRG?  ANSWER: Unless you
have spent over a year on your enhancement, the chances are that the Kit
offers A GREAT DEAL MORE!!!  Consider the following diagram, adapted from "The
Mythical Man-Month" by Frederick Brooks (Figure 1.1, p. 5):


                                P*3 --->
     ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÑÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»
 P*3 º    In-house Program           ³  A Programming System         º
  |  º    or                         ³  Component                    º
  |  º    Personal Program           ³  (Interfaces, Integration)    º
  |  ÌÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍØÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ͹
  V  º  Commercial-Quality Product   ³  Commercial-Quality Systems   º
     º  (Generalization, Testing,    ³  Product                      º
     º   Documentation, Maintenance) ³                               º
     ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÏÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ



   Your enhanced LOCKS.PRG is an example of a program in the upper-left box.
Brooks says that as a rule of thumb, it takes about 3 times the effort to make
your product into a commercial-quality product with generalized inputs and
outputs, thorough testing, user documentation and installation procedures, and
maintenance (bug-fix releases, releases to support new operating system
versions, and so on).

   Also as a rule of thumb, Brooks says it takes about 3 times the effort to
make your program into a component in a system of interacting component
programs. This effort reflects the design, debugging, implementation, and
documentation of the interfaces to the other components in a programming
system.  A commercial-quality programming system is about 9 times more effort
than a stand-alone in-house program.

   Assuming that your enhancement of LOCKS.PRG includes a complete semaphore
facility, the Kit is about 9 times more extensive.  This is because the dMILL
All-Networks Productivity Kit is a commercial-quality set of interacting
programming components.  If your enhanced LOCKS.PRG does not include a
complete semaphore facility, the Kit is probably about 50 times more extensive
than your enhanced LOCKS.PRG.