Date: Fri, 28 Dec 2007 08:25:34 -0500 From: "Aryeh M. Friedman" <aryeh.friedman@gmail.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: BSD license compatible hash algorithm? Message-ID: <4774F94E.50203@gmail.com> In-Reply-To: <9bbcef730712280518k56696002w1437ec3469e2eeb2@mail.gmail.com> References: <5950EE0C-383D-4D6B-9991-A0DEABD2ADE4@u.washington.edu> <20071228003716.GB48997@lor.one-eyed-alien.net> <B8D4C3C6-B867-4550-9F17-4DC6930D10E2@u.washington.edu> <fl2qiv$qoh$1@ger.gmane.org> <4774EF27.90307@gmail.com> <9bbcef730712280454w6b6f5e17s33631223d5571f83@mail.gmail.com> <4774F42C.5030105@gmail.com> <9bbcef730712280510v14806e7exb960f5da5f05e4d@mail.gmail.com> <4774F651.7060905@gmail.com> <9bbcef730712280518k56696002w1437ec3469e2eeb2@mail.gmail.com>
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Ivan Voras wrote:
> On 28/12/2007, Aryeh M. Friedman <aryeh.friedman@gmail.com> wrote:
>
>> Depends on the size of the table... I work with a algrothem that
>> regularly has tables between 2^32 and 2^64 buckets (even though
>> the we use a slightly different terminology)
>
> This looks like an interesting project - are you using hashes not
> for speed but as a generic storage organization algorithm?
>
> And, I think at least some of the popular non-crypto hash
> algorithms could be easily extended to work with 64-bit integers -
> are you really using the "big" hashes for this?
>
Yes using it as a DB table indexing, the exact details are under an
NDA but I can give some numbers though like a table lookup on a 2^32
record table requires no more then 4 disk reads (averages out to
between 3 and 4) and 2k or RAM [namely gives O(log_k(n)) we have,
successfully used k>=256 even though k=256 is the most natural value,
time performence and O(1) when considering primary store requirements
only... in other words when the table size = 2^processor word size you
need word size/8 lookups at most to find anything])... hopefully once
the patents are in place I can give more details (I am hoping to make
the reference implementation as FOSS as possible {while not
invalidating the strength of the patent} [see my blog for details on
the business model I am planning])
- --
Aryeh M. Friedman
FloSoft Systems
http://www.flosoft-systems.com
Developer, not business, friendly
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