Significant digits in a float?

[Mark H Harris]

Since calculators had started to appear, I never did get formal
training in slide-rules. The LL scales still require me to glance at a
guide book...

I regret that I never risked the $35 dollars when my college bookstore
was closing out the slide-rule display. They had the top Post bamboo
laminate rule at half price. At the time I'd bought an HP-25 calculator
[they phased out the HP brand a year or two later -- apparently RPN was too
confusing].

Half way through my senior year the HP-65 "gold key" calculator was
available for about $800.00 dollars. That sucker was programmable and
had magnetic strip recorder for off-loading storage... but I digress. We
all had our priorities... one guy bought one; the rest of us bought
cars. ---for about the same price too!

I used my rule well into college; the first calculator I owned was
the Rockwell 63R --- "The Big green numbers, and the little rubber feet!"

marcus

 

[Steven D'Aprano]

On Tue, 06 May 2014 09:59:22 -0500, Mark H Harris wrote:

[...]

I used my rule well into college; the first calculator I owned was
the Rockwell 63R --- "The Big green numbers, and the little rubber
feet!"

Guys, heaven knows I'm guilty of the occasional off-topic post myself,
and I'm not obsessive about these things, but there comes a time in every
off-topic thread where the right thing to do is to label it off-topic.
And this thread has long passed that time!

 

[Joel Goldstick]

HP 35. $350 in 1973 or 4. Still have it somewhere. Tom yay!

 

[Mark H Harris]

I’m surprised no one has jumped in to defend/tout the Dietzgen slide rules
(which I always thought were the ultimate). Mine (their Vector Log Log) is
one of their Microglide series that had teflon rails inserted in the body
and is still totally stick-free after nearly 50 years.

http://www.marksmath.com/slide-rules/img/ed-n1725.jpg

The above link is nice for the Dietzgen Microglide. It doesn't have the
CF/m DF/m scales, but is a very nice Vector type log log. Most of my
drafting equipment from the same era was Dietzgen; it looked like the
previous video post featured the same/

My dad has one of these; but I can't get him to part with it yet...



marcus

 

[Dennis Lee Bieber]

Actually, I think you're right. I never used the a yellow rule, but
I will say that my N4-T never caused me any eye-strain (but I was
younger then).

T was "Traditional" (ie; black on white)

The N4-T was a flat white also... very easy to read. I really don't
know what all the 'yellow' hype was all about.

Same thing as yellow chalk on a green board, vs white chalk on a black
board... Less extreme brightness levels, focusing on where the eye is most
sensitive (yellow-green)

 

[Adam Funk]

Special markers for: dozen, gross; a scale for "non-metric measures" to
metric equivalents -- US Bushel, UK ("brit") bushel, US gallon, UK gallon,
short and long tons, a few Russian units, "Pud" and "R.t." which appear to
map to cubic inch and cubic foot; markings for % (discount and mark-up)

And a scheme for simple interest calculations (which may explain why
the CF/DF scales are longer than the C/D scales): "Move the main cursor
line over the principal on scale DF -- the principal must be taken only on
scale DF -- set the rate per cent on the scale CI, under the short cursor
line, and read the interest on the scale DF or D in line with the number of
days on the scale CF or C." {yes, just to the left of the normal cursor is
a short line only over the inverted C scale}

Interesting, thanks.