Re: evolution of arithmetic, was bytes, The joy of FORTRAN

On Thu, 06 Mar 2025 05:11:35 GMT, Charlie Gibbs wrote:

On 2025-03-06, Lawrence D'Oliveiro <ldo@nz.invalid> wrote:
 

On Wed, 5 Mar 2025 03:00:44 -0000 (UTC), John Levine wrote:
>

sometimes it's something like the the nearest 1/100 of a percent which
would be four digits after the decimal point.

>
But percentages typically do not go into the millions, do they. The
term for those hundredths of a percent is “basis points”. So for
example if the OCR is set by the Reserve Bank at 5.75%, then arithmetic
involves multiplication/division by a factor like 1.0575, which should
be doable quite accurately for many common money amounts within 15
figures.

 
Mainframes in the '70s and '80s tended not to have support for 64-bit
integers.

Remember the CDC and Cray machines had 60-bit or 64-bit word lengths.

Decimal arithmetic was the only game in town, and techniques
developed appropriately.

Derivatives trades became popular in the 1980s, as I recall. The need to
operate in real time tended to rule out mainframes.

I think NeXT machines were commonly used in that (niche) market, once they
became available.