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From: "Magnus Sparf" <magnus-s@dsv.su.se>
Newsgroups: comp.lang.ada
Subject: Re: Direct_IO problem -- generic package problem
Date: Fri, 13 Jul 2001 10:16:00 +0200
Organization: National Defence Research Establishment, Sweden
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<tmoran@acm.org> skrev i meddelandet
news:4Pm37.178065$%i7.116159417@news1.rdc1.sfba.home.com...
> >Instantiate Direct_IO with constrained subtypes of Matrix for the types
> >of interest.
> i.e.
> >My own ideas is to create separate databases for all eight databases
> >that uses DB (CAR_DB, BOAT_DB, HOUSE_DB...) with specified values for
> >MATRIX, but that seems like a lot of work and not very objectoriented.
>   If you are doing direct IO all the records in a given file need to
> be the same size anyway, so it certainly is reasonable to instantiate
> Ada.Direct_IO once for each of the eight database files.  Did the
> old program actually mix different size records in a single file?  How
> did it know where to look for record N?

No,  the program created a separate file for each database.
The big problem for me with this program is that the part about the
database(s) i totally uncommented and there is no documentation what so
ever. And the person who originally designed is gone since 13 years ago and
probably doesn�t remember anything.

> As for OO, if you have a
> root Matrix tagged type make it abstract, then each of the eight
> children should have its own overide of its input/output routines
> using the appropriate instantiation.

Sounds like a great concept

/Magnus
magnus-s@dsv.su.se