Re: A Customer's Request For Open Source Software

[Marin David Condic <nobody@noplace.com>]

I agree that concurrency is difficult. What I'm talking about is that if 
you built a core accounting engine that presented itself to the rest of 
the application as an "object" and if that engine initially just 
operated within RAM (load and store to a file), you'd have a useful 
start. If you wanted to later go to a concurrent system you could either 
wrap the core in a server that serialized the access (serve just one 
user at a time in a read/modify/write kind of protocol) *or* if you 
thought that would be unreliable, you could rebuild the core with a 
database beneath it and present the same interface to the rest of the app.

Its mostly a way of saying "Start with a nice simple, achievable goal 
that produces something useful. If it succeeeds in comiing to fruition, 
worry about upgrades later." All too many projects that get discussed 
here end up on the trash heap of obscurity and decay because the owners 
get far too ambitious for their own good. Its a natural human tendancy 
and one that strikes us engineers particularly hard. It has to be 
overcome if you want to actually get something done.

MDC


Christopher Browne wrote:
> 
> 
> There is a strong tendancy for systems designed in this manner to NOT
> play well when they move over to allow concurrency.  I think I can
> characterize it all in one word: "Windows."
> 
> In spite of there being Windows NT around, which _was_ designed as a
> multiuser multitasking system, since so much of the software had its
> genesis with companies that assumed ONE user running ONE program on
> some variation of Windows 95, which was a thin layering of GUI atop
> MS-DOS, what we see now is that "Windows applications" are basically
> designed for a single user OS, and most don't play well if you have
> multipel instances of things around.
> 
> Concurrency is _hard_, and if you don't design it in at the beginning,
> it is quite likely that by the time you get around to it, the system
> design will probably preclude having it _really_ work...


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Marin David Condic
I work for: http://www.belcan.com/
My project is: http://www.jast.mil/

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