ENG mode, n+1?

[brouhaha]

(01-13-2014 10:32 PM)Tim Wessman Wrote:  So I was just wondering why on the 48 series and onwards (maybe in earlier units too?) the ENG display mode actually seems to do n+1 and is mislabeled as "enter decimal places to display".

For example, on the 48-50, ENG 4 would show this:

123.456789: 123.46E0
1234.56789: 1.2346E3

and so on. So ENG 4 actually shows 5 digits and has nothing to do with "decimal places". What was the first place it started behaving like this? What is the reasoning behind the N+1 and why the mislabeling as "decimal places"?

I think the rationale was for "ENG n" mode to show the same total number of digits as "SCI n" would show. AFAIK, this originated with the HP-25 in 1975.

The description may well be poor, but I think the behavior is desirable. I wouldn't want an "ENG 3" mode that resulted in 4, 5, or 6 significant digits displayed; I'm happy with it always showing four significant digits.