What's a Number, physically?

[kennedy]

How does FileMaker store Numbers?

IEEE Single-precision? IEEE Double-precision?

Multiple-precision? Fixed-point? Text?

This can have dramatic effect on applicability. For example, if single-precision float, then its wholly unsuitable for many financial apps. But obviously fixed-point (good for accounting) wouldn't work well for scientific and engineering apps. Multiple-precision would be best, though it could be very expensive.

How about calculations? What form are they done in? Similar points, though somewhat less critical, if the app designer is careful.

[LiveOak]

Single precision and double precision are somewhat relative to the word size of the machine being used. I would guess that FM stores numbers as fixed point representations, as it doesn't seem to be able to handle large floating point numbers. It certainly seems capable of what would be considered multiple precision by some standards. Whether all numbers are stored in multiple precision or some sort of automatic switching takes place based upon value, only the designers would know.

-bd

[kennedy]

Based on more experiementation, I think Number fields are actually just stored as Text fields with different default treatment. Witness that it will actually store any text string you want... but then displays it (by default) with any non-numerics removed. But the full string is there.

In contrast, calculations on numbers appear to be limited to 15 decimal digits of precision, which would imply it uses double-precision floating point. Is that guaranteed across all platforms? Is IEEE guaranteed?