Re: Communications of ACM: Sir, Please Step Away from the ASR-33!

[Simon Wright <simon@pushface.org>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:

> UML is absolutely unusable for distributed systems, but I don't want
> to get into it. Suppose I need to invert a 10x10 matrix, and, please,
> no message boxes, customers get fancy when see that mess.

It would be very unproductive to model matrix inversion in UML. You'd
use a library function in your language of choice.

Unless, of course, the problem you have to solve is to invert a
1000000x1000000 matrix over a distributed system, in which case you must
deal with how to distribute the solution; and designing the necessary
software modules and communications between them would be of the
essence. At which point, why would UML be inappropriate? It [can be used
as] a language for discussing problems at an abstract level, so you can
see the wood for the trees.


>>> Relation is a Boolean
>>> operation of two arguments. 
>> 
>> I thought that a relation is a thing between two things.
>
> http://en.wikipedia.org/wiki/Binary_relation

No, no! it's relationship or association, _quite_ a different concept.


There's an excellent article at
http://knol.google.com/k/how-to-build-articulate-uml-class-models by my
hero Leon Starr.