1996-05-23 - Re: The Crisis with Remailers

Header Data

From: “Perry E. Metzger” <perry@piermont.com>
To: R.Hirschfeld@cwi.nl
Message Hash: 45fd708490812da5db8fea112a91385412fcf770988aa90ccf603977e3d09cfa
Message ID: <199605221904.PAA23720@jekyll.piermont.com>
Reply To: <9605221739.AA03647=ray@groen.cwi.nl>
UTC Datetime: 1996-05-23 08:33:54 UTC
Raw Date: Thu, 23 May 1996 16:33:54 +0800

Raw message

From: "Perry E. Metzger" <perry@piermont.com>
Date: Thu, 23 May 1996 16:33:54 +0800
To: R.Hirschfeld@cwi.nl
Subject: Re: The Crisis with Remailers
In-Reply-To: <9605221739.AA03647=ray@groen.cwi.nl>
Message-ID: <199605221904.PAA23720@jekyll.piermont.com>
MIME-Version: 1.0
Content-Type: text/plain

R.Hirschfeld@cwi.nl writes:
> Despite the ugliness of floating point arithmetic (lack of
> associativity, for example) and my general distaste for it, I would
> have to agree that 64-bit floats are higher precision than 32-bit
> fixed-points, since more than half the bits are mantissa.

However, accounting systems DO NOT use 32 bit fixed point arithmetic.

One client of mine had around $10Billion under management. Do you
think they were doing their accounting on a system that could only
deal with fixed point numbers of 45Million or so? Hell, individual
trades are larger.

Floating point systems are built to do approximate math on a very wide
range of number sizes. Accounting systems require exact math -- down
to the cent. Floats aren't suitable.

Anyone who needs to understand why should go off and read Knuth,
Volume 2.