Record-access libraries (Was: Re: VMS vs. UNIX file system)

Arturo Perez Ext. aperez at blazer.uucp
Tue Oct 4 04:24:14 AEST 1988


>From article <e1Lt8#2CJhqZ=eric at snark.UUCP>, by eric at snark.UUCP (Eric S. Raymond):
> In article <3717 at encore.uucp>, bzs at xenna (Barry Shein) writes:
>> Eric, I disagree and think you dismiss the value of record access
>> libraries too glibly. There's more to it than fixed and blocked record
>> formats.
>> 
>> Consider various associative schemes like ISAM or B-TREE management...
> 
> I agree that libraries like UNIX dbm are a Good Thing -- but then ISAM, B-TREE
> management, and other associative retrieval schemes are not within the scope
> of the original question. Let's not muddy the waters by confusing 'record
> access' in the RMS "fixed and blocked record" sense with more general database
> access techniques.

Why needlessly restrict the scope of the argument? I admit, the question I
originally asked was a query regarding the availability of record-access 
libraries under Unix.  However, I believe that any retrieval method is
a valid conception of "record."  After all, aren't we just trying to
optimize the retrieval of data from the file?  Isn't that what ISAM,
and fixed records and all that other cruft is about?  

I can almost (but not quite :-) concede your point that is isn't worth
optimizing the access of fixed block files.  But say I had a fixed block
file that I only accessed randomly, occasionally sequentially but not
too often.  Wouldn't it be a useful embedded attribute of the file?
That way the kernel wouldn't waste too much of its time trying to do
readahead for me, which I won't be using anyway. 

I guess I am starting to diverge.  However, I do believe that there
are uses for standard access methods that take these things into 
account.  What I don't understand is why isn't anyone providing them.






Arturo Perez
ComputerVision, a division of Prime
primerd!cvbnet!aperez
The difference between genius and idiocy is that genius has its limits.



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