The physics prof who gave me my start would always get this kind of fond, nostalgic look in his eye whenever anyone mentioned "the days of punch card programming". So, naturally, I took an old slide rule and mounted it in a shadowbox with lettering that said "IN CASE OF EMERGENCY BREAK GLASS" when I got ready to graduate. He got a tremendous kick out of it.
Ask HN: Is there anyone here who still uses slide rules?
111–120 of 131 posts
Re: Ask HN: Is there anyone here who still uses slide rules?
#112in spite of my age, I'm one of first digital native. I never used it and nobody explained me how to use. At same time I avoid most of analog instruments: multimeters, scope meters, calipers.
Re: Ask HN: Is there anyone here who still uses slide rules?
#113I have four now, and even go out of my way to use them a bit.
My favorites from my collection are a little Dietzgen No 1773, which is surprisingly featureful for something that can fit in a pocket, and a Faber-Castell Novo-Biplex 2/83N, which is kind of one of the big guns for slide rules.
Re: Ask HN: Is there anyone here who still uses slide rules?
#114I have four now, and even go out of my way to use them a bit. My favorites from my collection are a little Dietzgen No 1773, which is surprisingly featureful for something that can fit in a pocket, and a Faber-Castell Novo-Biplex 2/83N, which is kind of one of the big guns for slide rules.
What I _really_ want, now that I have the Faber-Castell, is a Curta.
Re: Ask HN: Is there anyone here who still uses slide rules?
#115Earlier quoted context omitted.
I've never used a slide rule but recently developed an interest in them (and also in nomograms [1]) My fascination stems from a belief: that slide rule usage helps users develop a certain intuition for numbers whereas the calculator doesn't. To illustrate, suppose someone tries to multiply 123 and 987 with a calculator but incorrectly punches in 123 and 187. My hypothesis is they'll look at the result but won't suspe…
With a slide rule you always have to estimate the expected answer in your head before you begin any calculation. So you develop a feel for how quantities scale with multiplication. With a slide rule you can only multiply the significant digits, not the magnitudes -- which you have to do in your head. So you do exactly the same thing with the slide rule to multiply 123 and 987, 1.23 and 9.87, and 1,230 and 9,870. In a…
You don't have to multiply the powers of ten in your head. In your examples, the slider of the slide rule must be moved to the left of the body of the rule. This means the number of digits left of the decimal point in the answer is the sum of the number of digits left of the decimal point in the two multiplicands.
If the slider had been to the right of the body, the number of digits left of the decimal point in the answer is the sum of the number of digits left of the decimal point in the two multiplicands MINUS 1. .
Re: Ask HN: Is there anyone here who still uses slide rules?
#116Back in 1969 I had a summer job in the engineering department of a factory. The Chief Engineer was an old guy who was a slide rule artist. He taught me how to solve second degree equations (ax^2 + bx + c = 0) with just a slide rule. The standard formula that I had learned in high school includes adding and subtracting, which a slide rule cannot do. His method involved pulling out the slider of the slide rule and inserting it backwards. Then, through some clever manipulation using the D and B scales (which now faced each other) and the A and C scales, he could actually solve the equation with just the slide rule. I wish I could remember exactly how it was done.
Re: Ask HN: Is there anyone here who still uses slide rules?
#117The children's maths/puzzle book "Nut-Crackers" (John Jaworski and Ian Stewart, 1971) had a slide rule printed at the back of the book - two strips each numbered 1-50 - to cut out and try out.
The authors commented "If you get really interested you can make much more accurate slide rules, or you can buy them for about £1." I fear not any more...
Re: Ask HN: Is there anyone here who still uses slide rules?
#118I do not use, and have never used, a slide rule. My grandfather was an aeronautical engineering / materials scientist for McDonnell Aircraft, and did a lot of foundational work on heat shields for early space flight (or so I am told). He was eventually named a McDonnell Douglas Fellow, back when there were fewer than 15 Fellows - the company, at the time, took out a full-page ad in Aerospace Magazine announcing it. I…
Me too! My grandfather worked in construction among other things and gave me his slide rule some years before he died. He showed me how to use it but I don't remember (though what he gave me came with instructions).
I too cherish it.
Re: Ask HN: Is there anyone here who still uses slide rules?
#119Earlier quoted context omitted.
With a slide rule you always have to estimate the expected answer in your head before you begin any calculation. So you develop a feel for how quantities scale with multiplication. With a slide rule you can only multiply the significant digits, not the magnitudes -- which you have to do in your head. So you do exactly the same thing with the slide rule to multiply 123 and 987, 1.23 and 9.87, and 1,230 and 9,870. In a…
You don't have to multiply the powers of ten in your head. In your examples, the slider of the slide rule must be moved to the left of the body of the rule. This means the number of digits left of the decimal point in the answer is the sum of the number of digits left of the decimal point in the two multiplicands. If the slider had been to the right of the body, the number of digits left of the decimal point in the a…
Yes. I don't recall doing this, though. Maybe because in scientific and engineering calculations we often worked in scientific notation so 'digits to the left of the decimal point' wasn't meaningful - we had to keep track of the exponents.
Re: Ask HN: Is there anyone here who still uses slide rules?
#120Earlier quoted context omitted.
A key idea is that addition for logs is equivalent to multiplication. To multiply two numbers you line them up on a log scale and then read out the sum, which is equivalent to the product. There is much more they can do but that was one aha moment when my dad showed me his.
I've never used a slide rule but recently developed an interest in them (and also in nomograms [1]) My fascination stems from a belief: that slide rule usage helps users develop a certain intuition for numbers whereas the calculator doesn't. To illustrate, suppose someone tries to multiply 123 and 987 with a calculator but incorrectly punches in 123 and 187. My hypothesis is they'll look at the result but won't suspe…
It's not the number of actions, it's because the slide rule is analog and physical. The smaller numbers are to the left, the larger to the right, and you have to slide the rule to the first number, then the hairline cursor to the second number. There's no way you could mix up a large number like 987 with a small number like 187.