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Date: Mon, 26 Sep 2016 05:39:04 -0700 (PDT)
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Subject: Re: Question on bounded / unbounded strings
From: brbarkstrom@gmail.com
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Xref: news.eternal-september.org comp.lang.ada:31900
Date: 2016-09-26T05:39:04-07:00
List-Id: <comp.lang.ada>

On Monday, September 26, 2016 at 3:29:20 AM UTC-4, Dmitry A. Kazakov wrote:
> 
> > I expect Dimitry wouldn't like putting Bounded_Strings into
> > Direct_IO files, where they're useful for fields in records that act like
> > variable length character strings in databases.
> 
> Surely not. Bounded string is a private type (A.4.4).
> 
> You *never* use such for any external activity, that would make your 
> program non-portable and thus the DB too.
> 
> Therefore a text field of Direct_IO element record should always be a 
> subtype of String and never bounded or unbounded string.
> 
> BTW, in many cases it is better to use Direct_IO rather as a block I/O 
> medium. You never know if all application level objects would fit into a 
> single block. My implementation of external B-trees keeps tree nodes in 
> Direct_IO blocks with indices pointing to the blobs spread over other 
> blocks arranged as a persistent memory pool. So there is no limitation 
> to how large an item could be and no space loss of underfilled blocks.
> 
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de

I wouldn't copy a Direct_IO file from my Windows machine to my
Linux box and expect to use it without reconstructing the file.  But then
I'm not working in a corporate environment with heterogeneous systems.
I've got enough problems with getting the math in the algorithms to work
properly, whether doing critical path calculations or Bayesian analysis
of user properties.

Thanks for the interest, even so.

Bruce B.