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From: kahn@kahn.pdial.interpath.net (Larry Kahn)
Newsgroups: comp.lang.ada
Subject: Re: WE NEED A GOOD Ada SORT PACKAGE!
Date: 6 Nov 1994 15:28:06 GMT
Organization: Dynamics Research Corp.
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 <39b7dl$1hit@obelix.uni-muenster.de> <39f622$p7d@gnat.cs.nyu.edu>
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Date: 1994-11-06T15:28:06+00:00
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In article <39f622$p7d@gnat.cs.nyu.edu>, dewar@cs.nyu.edu (Robert Dewar) says:
>
>Jahn, the idea of doing quicksort directly on a disk gives me a headache
>just thinking about the poor disk arm!
>
>no, you definitely can't do this if you are interested in efficiency,
>even on disk files you definitely need some multi-phase merge sort.
>For Realia-COBOL, I implemented the disk sort with a 64 way polyphase
>merge, and it seems to be the fastest external sort around, or at least
>was at the time I was paying attention to COBOL!
>

I have a shell sort example of a generic in Ada but it does the sort in memory..

For the tests we Did it was faster than a quicksort probably due to the overhead
of the quicksort code (this on a dec compiler with around 5000 items)

don't remember where the trade off point was where quicksort was faster
but sure there was one.....

The original source was from the following book:

-- from Software Components With Ada, Grady Booch, page 469

Laurence G. Kahn
Senior Software Engineer
Dynamics Research Corp.