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Know How To Use a Slide Rule?

kdawson posted more than 6 years ago | from the try-your-hand dept.

Math 388

high_rolla writes "How many of you have actually used a slide rule? The slide rule was a simple yet powerful and important tool for engineers and scientists before the days of calculators (let alone PCs). In fact, several people I know still prefer to use them. In the interest of preserving this icon we have created a virtual slide rule for you to play with." Wikipedia lists seven other online simulations.

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I learned how to use my slide rule... (5, Funny)

moosejaw99 (1052622) | more than 6 years ago | (#20784119)

at around 10 years old. I've been using it ever since, and don't plan on ever stopping.

Re:I learned how to use my slide rule... (1)

ColdWetDog (752185) | more than 6 years ago | (#20784193)

Yep, still have my Pickett Model 500T Ortho Phase Log Log (whatever the hell that means) slide rule. A little stiff from decades of disuse, but hell, the batteries are fine!

Re:I learned how to use my slide rule... (1)

snowraver1 (1052510) | more than 6 years ago | (#20784205)

Hmm... Then maybe you can help me here. I can't find where the batteries go, and once we get that going, how do you load Pimpquest?

Of course (1)

linuxboredom (1054516) | more than 6 years ago | (#20784135)

I can use one (only a linear slide rule, though), but I definitely prefer a calculator. The calculator gets you much more precision at a quicker rate.

Re:Of course (5, Insightful)

mabhatter654 (561290) | more than 6 years ago | (#20784423)

but in reality, justifying precision more than 4 significant places is really difficult using proper scientific/engineering methods. For instance 4 decimal places in surveying takes you to an inch range even over a mile of distance with hand tools. Average slide rules can do 2-3 fancy ones can hit that last place.

Re:Of course (2, Insightful)

kalidasa (577403) | more than 6 years ago | (#20784495)

For engineering, you're right. For other sciences: well, let's just say that you wouldn't want to have to calculate an Earth-Mars transfer orbit with a slide rule.

Re:Of course (1)

zoward (188110) | more than 6 years ago | (#20784463)

Circular slide rules use the same logarithmic principles and scales (A,B,C,D,K,S,T, etc) that the linear ones do, so if you know how to use a linear slide rule, you know how to use a circular one.

Re:Of course (1)

rubycodez (864176) | more than 6 years ago | (#20784677)

and with a circular one you don't have that annoying "overflow from one end so I have to go from the other end" problem, it's actually the circular slide ruler going back to linear who's going to be bitching.

Re:Of course (3, Interesting)

rubycodez (864176) | more than 6 years ago | (#20784907)

but with a slide rule you can see a range of answers around the result for varying the factors. that process is extremely slow on a digital calculator. plus a slide rule forces you to think of the proper magnitude of the answer, with calculator people trust without thinking and "missed decimal point" or just fat-finger error gets believed more readily.

Of course (3, Interesting)

Kozar_The_Malignant (738483) | more than 6 years ago | (#20784153)

I did college physics, organic and physical chemistry with my trusty Pickett aluminum log-log slide rule. You needed one for real geek cred in those days.

Re:Of course (5, Funny)

Daniel_Staal (609844) | more than 6 years ago | (#20784271)

I've never had one required (courses tended to require graphing calculators by the time I got to them), but I found one in my grandpa's desk and learned to use it. Then I carried it with me to high school and gave it to anyone who asked to borrow my calculator.

Re:Of course (1)

arivanov (12034) | more than 6 years ago | (#20784627)

Same here.

Worked a treat.

As a matter of fact, it is probably faster to do some computations with it compared to a calculator or a computer if you know how to use it (I have forgotten it completely now) and if you are happy with its precision.

Re:Of course (2, Funny)

confused_demon (1161841) | more than 6 years ago | (#20784385)

I grew up after hand-held calculators were ubiquitous, and after slide rules were rare. However, it was also before calculators were allowed on exams, but slide rules were! So, I learned how to use a slide rule. Later on, I was allowed to use a slide rule with all my useful chemistry and physics equations written on it, even though programmable calculators were forbidden b/c they might have formulas stored in them.

back in the day (2, Interesting)

OffTheLip (636691) | more than 6 years ago | (#20784157)

When I took HS Chemistry a slide rule was required. The instructor spent a bit of time explaining how to use it and we were quizzed later. While it lacked the precession of modern calculators we managed to solve complex problems. My dad earned an engineering degree back in the 50's using only a slide rule.

Re:back in the day (1)

CryptoEngineer (755293) | more than 6 years ago | (#20784629)

I'm 50, and of the generation that went through the transition. In middle and high school we used slide rules, and books of log and trig tables for physics, chemistry, and maths. Calculators started to appear when I was about 13, and I got a 4 function model when the price came down to about 200 dollars. There was a *lot* of debate about the wisdom of letting students use them, as they wouldn't understand the algorithms involved in, say, long division, and in exams, students who had them would be at an unfair advantage (there are still some restrictons today, I understand). I went into college still using a slide rule (1975), but by the time I left, they were considered obsolete.

Slide tool was great when I was 10 (1)

Karaman (873136) | more than 6 years ago | (#20784159)

When I was 10 years old my father gave me one as a present! It made complicated calculations very easy task. It was even faster than the computer :)

I still use it (1)

Rosco P. Coltrane (209368) | more than 6 years ago | (#20784165)

Mainly to give rough answers to vaguely complex calculations, to check if this or that engineering decision is sound, or not way off the mark. For me, that's the main interest of a slide rule today: not precise answers, but quick validation of a calculation. For anything more precise, I juse my trusty HP48.

Buy your own! (2, Interesting)

PlatyPaul (690601) | more than 6 years ago | (#20784169)

In case you'd like to work with the real thing, take a look here [sliderule.ca] for some info on places to buy slide rules these days.

My mother recently bought one in a wave of nostalgia. I can certainly understand the physical appeal - the soft susurration of the pieces gliding against each other, the comforting grip of the leather carrying case, the art of perfectly lining up the dashes to the limits of human precision. If computers were that tactilely slick, nerds might rule the world.

Me! (1)

foobsr (693224) | more than 6 years ago | (#20784175)

When I started with what they call 'Gymnasium' over here, even pocket calculators were not at hand and the system/360 was not yet introduced ;)


Poll (0, Offtopic)

Artaxs (1002024) | more than 6 years ago | (#20784209)

The poll on that page has a great "Cowboy Neal" option.

I believe that the Government is doing all it can to ensure that toys are 100% safe

Strongly agree
Dont know
Strongly disagree
They should all come with a free set of steak knives

Hooray for progress (2, Insightful)

the_humeister (922869) | more than 6 years ago | (#20784215)

There's a reason we don't use slide rules, abacuses, buggy whips, etc. - we have better tools now. I used to have one when I was a kid back in the '80s, never really figured out what it was for, especially since we had scientific calculators instead.

Re:Hooray for progress (0)

Anonymous Coward | more than 6 years ago | (#20784759)

There's a reason we don't use slide rules, abacuses, buggy whips, etc.

Buggy whips?

Around here (4, Funny)

Tarlus (1000874) | more than 6 years ago | (#20784217)

The only slide rule around here is to not push the kid in front of you.

Re:Around here (1)

PlatyPaul (690601) | more than 6 years ago | (#20784369)

Then I guess you haven't built your own [sphere.bc.ca] yet, have you?

(website warning: fugly graphics design!)

Re:Around here (1)

Tarlus (1000874) | more than 6 years ago | (#20784479)

(website warning: fugly graphics design!)
Wow, no kidding... 1996 called...

Re:Around here (0)

Anonymous Coward | more than 6 years ago | (#20784909)

Yes, that rotating email gif used to be ubiquitous on the web. It still rocks.

I wish (1)

htricia (1133795) | more than 6 years ago | (#20784235)

Unfortunately I have never had a chance to learn to use a slide rule. I am a third generation math geek and there are plenty of old math books around but not a single slide rule to be found. I feel like I am lacking a certain level of geekness.

No (1)

Corporate Troll (537873) | more than 6 years ago | (#20784241)

It was still taught at school (University?) in the day and age of my parents. Not anymore in my day and age (I was born in 1976, use your slide rule to calculate my age ;-) ). Both my mom and dad still have theirs.

What???? (1)

BlackPignouf (1017012) | more than 6 years ago | (#20784247)

Please tell me when it really works! I got:

Yep (1)

zoward (188110) | more than 6 years ago | (#20784591)

Please tell me when it really works! I got:

Just for haha's I got out my trusty old Concise circular No. 300 and checked this. You only get three sig fig's, so it actually comes out to ~65500.

E6-B (1, Informative)

Anonymous Coward | more than 6 years ago | (#20784263)

The E6-B [mypilotstore.com] that every pilot learns to use in ground school is basically a special-purpose circular slide rule.

You know you're a math nerd when... (1)

paladinwannabe2 (889776) | more than 6 years ago | (#20784265)

You see the article and think "the virtual slide rule I created is better than this one!" Too bad my University stopped hosting it (they stop hosting student web pages 6 months after you graduate).

Um No. (4, Interesting)

VonSkippy (892467) | more than 6 years ago | (#20784269)

I also don't know how to use a Flintlock rifle, trap/clean/spit roast a hare, catch a fish with my bare hands, hitch a wagon to a horse, or build/make/use a butter churn.

Since I live in the 21st century, I don't really lose sleep over those things.

Re:Um No. (2, Insightful)

pclminion (145572) | more than 6 years ago | (#20784325)

Sounds like if the global shit ever hits the fan, you're simply going to DIE, because you have no ability to care for yourself.

Living in modern civilization is no excuse to be ignorant.

Re:Um No. (1)

Chineseyes (691744) | more than 6 years ago | (#20784405)

I think you severely underestimate peoples ability to adapt. If civilization as we know it were to collapse I'm sure most of the people on slashdot are intelligent enough to figure out how to survive on their own. Now if your argument was that they might not be physically fit enough to do so I might have to agree with you.

Re:Um No. (3, Informative)

rubycodez (864176) | more than 6 years ago | (#20784763)

actually, ignorant people in survival situations make all kinds of bad decisions and don't know how to treat or stabilize someone with injury. knowing poisonous from edible plants, cleaning properly cooking an animal without contaminating it, these are all things that people knew in that recent past but you'd better learn now rather than by trial and error (you die or are maimed for life if you're wrong)

Re:Um No. (1)

Wolvie MkM (661535) | more than 6 years ago | (#20784527)

So knowing how to use a slide rule will save humanity? Nice!

Re:Um No. (1)

pclminion (145572) | more than 6 years ago | (#20784577)

So knowing how to use a slide rule will save humanity? Nice!

Did you READ the guy's post? A slide rule might not save you, but being able to hunt, kill, clean, and cook an animal would probably be useful, don't you think?

The hilarity is that if civilization does go in the shitter, it's the so-called "hillbillies" who are going to absolutely own everyone's ass.

Re:Um No. (0)

Anonymous Coward | more than 6 years ago | (#20784713)

True, and if civilization DOESN'T "go in the shitter" the hillbillies will be hillbillies.

I think it's a reasonable choice to not know how to properly gut a pig if it means you don't have to gut a pig.

YMMV(and apparently does)

Re:Um No. (0)

Anonymous Coward | more than 6 years ago | (#20784827)

When I was a boy, we only had rocks for calculation, and we liked it! Integers rule!

And my slide rule converts into a crossbow, although computation suffers afterwards. But at least I can hunt fresh meat with it. When you're hungry in the woods, roast squirrel beats 5*ln 7.9 any day.

Do you hear that sound? (2, Funny)

benhocking (724439) | more than 6 years ago | (#20784829)

The hilarity is that if civilization does go in the shitter, it's the so-called "hillbillies" who are going to absolutely own everyone's ass.

For some reason, I'm hearing banjo music...

I did not need that visual.

Re:Um No. (1)

ColdWetDog (752185) | more than 6 years ago | (#20784587)

The veneer of civilization is thin, indeed. You never know how long the 21st Century is going to last. Get out of the basement and update your skillz:

I also don't know how to use a Flintlock rifle

That's pretty 18th century. You need to pick up the pace a bit [ak-47.us].

trap/clean/spit roast a hare

Again, you're a couple of centuries out of date. Get with the program here [amazon.com].

catch a fish with my bare hands

Alfred Nobel has the thing for you [illegal-fishing.org].

hitch a wagon to a horse

You actually do it the other way around (horse to wagon) - the horse is considered easier to move than the wagon, although in your case, given your apparent lake of experience with the things, I'll reserve judgment.)

build/make/use a butter churn

What part of the phrase "Google it" [google.com] don't you understand?

Re:Um No. (1)

everphilski (877346) | more than 6 years ago | (#20784777)

although in your case, given your apparent lake of experience with the things

Damn, you lay the sarcasm on thick :)

All I gotta say is, the amish are gonna pwn us all.

Still have mine... (1)

wtansill (576643) | more than 6 years ago | (#20784295)

Made it through chem 1, chem 2, and physics back in the day. I keep it around in case there's an extended power failure...

Re:Still have mine... (1)

MyLongNickName (822545) | more than 6 years ago | (#20784427)

In case you need to calculate how many cans of baked beans you can eat without killing yourself in a cloud of methane?

Re:Still have mine... (0)

Anonymous Coward | more than 6 years ago | (#20784851)

I still have two of mine - a K+E and a Post Versalog, both bamboo.

For extra nerd cred, I also taught slide rule for a couple of years.

the celticgeek

E-6 :) (1)

Subgenius (95662) | more than 6 years ago | (#20784357)

I tell ya, nothing like having a trusty E-6 sliderule device in your bag, just in case your batteries die. For some calculations, it is MUCH faster than an electronic flight computer.

Pocket slide rule (1)

Technician (215283) | more than 6 years ago | (#20784367)

I graduated high school when calculators ran on 4 AA batteries and would run for up to 8 hours. They were just under $150 for one that could add subtract multiply and divide and the big bonus, a percent key for the morons who couldn't move the decimal point two places.

I found the traditional slide rule large and bulky and often I would try to use the wrong index so my answer was off the scale off the other end (those who use them know what I'm talking about) so I was the owner of a circular slide rule. It fit my shirt pocket and had a pull out sheet with common conversions of weights and measures. I used the table as much as I used the slide.

One of the biggest uses for it was a sanity check of my math. If my math was out in left field for some stupid thing, the slide rule would quickly show my answer wasn't in the ball park.

Re:Pocket slide rule (0)

Anonymous Coward | more than 6 years ago | (#20784599)

I still have my circular slide rule exactly as you describe...the plastic sleeve has printed on it Physic is Phun

nerd phallus (4, Funny)

netsavior (627338) | more than 6 years ago | (#20784389)

the bigger the slide rule, the more accurate the calculation...

Re:nerd phallus (1)

snarkh (118018) | more than 6 years ago | (#20784831)

I presume you meant it as a joke, but it is true. You get more accuracy with a larger slide rule.
If you double the size of the slide rule, you double the accuracy for most tasks.

No, and what the hell is the index line? (4, Insightful)

cliveholloway (132299) | more than 6 years ago | (#20784391)

"The index line on scale C is always put over the number to be multiplied on scale D"

What's the point of explaining how it works if you don't explain what each of the terms used is?

Damn nerds...

Re:No, and what the hell is the index line? (2, Interesting)

ZERO1ZERO (948669) | more than 6 years ago | (#20784743)

I've read the site 10 times now - I still don't get how it works. Can someone explain it please. I'm not even sure I can even comprehend the instuctions. It seems to repeat it self - put the number on C over the number on D to be multiplied. Great done that - where's my answer.

And if you can use one... (1)

nweaver (113078) | more than 6 years ago | (#20784409)

(which I can, BTW, I stole my dad's many years ago, but I think it got lost in a random move), do you know WHY a slide rule works, and how to make a slide rule for addition and subtraction...

Circular Slide Rule (0)

Anonymous Coward | more than 6 years ago | (#20784413)

I use a circular slide rule at a few times in the week if I need to use a film camera to enlarge images that need to go to film.
They are great for proportions, especially in the print industry. It amazes me how many CSR's cant figure out proportions in this line of work.

Of course (4, Interesting)

Brett Buck (811747) | more than 6 years ago | (#20784433)

I use a slide rule DAILY. It's an extremely useful and (if you know what you are doing) both accurate and fast. For many engineering problems 3 or 4 sig. figs. is plenty enough. The advantages are well-known - the most important being the elimination of "false precision" that you can get with a mindless calculation with a 10-sig-fig calculator.

    They are also just good things to have around. A good slide rule (Aristo, Nestler, Faber-Castell, etc) is just such a fantastically well-made device that you really need to see it to appreciate. The precision is something you don't see these days. Even a lowly Pickett is nicely made.


Used!? (1)

sjvn (11568) | more than 6 years ago | (#20784445)

With 24 or so computers in the house, I still keep my now 30+ year old Dietzgen Polymath 1733 at my desk for quick math work. Like an abacus, if you really know how to use a slide rule, you can do basic math much faster than most people hammering on a calculator or PC numberpad.


Stupid virtual rule slide! (2, Informative)

BlackPignouf (1017012) | more than 6 years ago | (#20784461)

What is the point of having such a long rule, if you only see a part of it and cannot move both parts at the same time???????

At least, this one is usable:
http://www.antiquark.com/sliderule/sim/n909es/virtual-n909-es.html [antiquark.com]

Re:Stupid STORY! (0, Troll)

Zapped.Info (1113711) | more than 6 years ago | (#20784559)

What a complete waste of time and energy this story is...I'm not here for a history lesson or math 101...Geeze!

Calculate my age (1)

linuxwrangler (582055) | more than 6 years ago | (#20784465)

When I entered high-school I was using slide rules (still have some ranging back to great grandfather's). When I left high-school, programmable calculators were the rage.

The E6B [wikipedia.org] is still great for aviation.

Ahhh Nostalgia (1)

LorenzoV (106795) | more than 6 years ago | (#20784529)

I still have a Pickett metal slide rule with the yellow, not white, background color. I got it in 1964 when I went to tech school.

I also have a little gadget called an Addiator, a mechanical thingie that does addition and subtraction. They are both in the memorabilia box.

These days I use electronic calculators.

Yes, I'm that old.

no calculators (1)

hitchhacker (122525) | more than 6 years ago | (#20784561)

My freshman college physics professor didn't allow calculators on our exams, but he said we could use a slide-rule. So.. My dad lent me his and gave me a quick tutorial. I think I was the only student to show up with one. It actually slowed me down though (probably because I was still getting used to it).


I have (3, Informative)

ajs318 (655362) | more than 6 years ago | (#20784565)

When my grandad died, he left his "old" slide rules to my dad and me. My dad kept the original wood and cellulose one from the 1940s; I got the plastic one from the 1960s / 70s.

I soon got the hang of using it (and it can be quicker than a calculator sometimes), but I knew the general principle from before anyway. The main thing you have to remember is the slide rule only ever gives you the mantissa; you have to work out the exponent yourself. This means you have to do a rough mental calculation. People often put too much trust in calculators. When I was filling in order forms by hand in a previous job, I never used a calculator -- and I never got called out on a wrong total.

You had to know the "Reasonableness Test" (1)

Two99Point80 (542678) | more than 6 years ago | (#20784607)

A slide rule will give you a couple/few significant digits of the answer, but no notion of where the decimal point should be. Thus you had to have some sense of the magnitude of the expected result, which helped weed out implausibly large or small "answers".

An engineer I knew in the early '70s had a metal circular slide rule. Occasionally he would carry it around in both hands, with a matzoh cracker held against its underside with his thumbs. In the midst of a conversation, he would feign taking a bite of the slide rule, pushing the cracker forward at the last instant and crunching into it instead. The effect was startling...

Old School (1)

Enrique1218 (603187) | more than 6 years ago | (#20784609)

You have too much time on your hands. Why not simulate the abacus while your at it?! I study physics and I have not need for an slide rule. Matlab rules them all and everthing else is obsolete. I can't sit around all day doing mundane calculations. However, from my observations a tutor, calculators are being utilize too much in high school and the students suffer for it. It is one thing using technology to be productive and it is completely another thing to outsource thinking from your brain. Give them the slide rules, let them earn the calculators!

I taught myself how to use one (1)

3waygeek (58990) | more than 6 years ago | (#20784645)

back in the third grade (roughly 1971-72). I was in my local Target when I saw a cheap plastic slide rule on the shelf -- we were just starting to learn multiplication, and the package said that it could do that, so I figured what the hell, and bought it.

As promised, the slide rule was quite useful for multiplication and division. On the back of the slide, there were sine, log, and tangent scales -- that led me to look those things up in Dad's copy of Machinery's Handbook [industrialpress.com], which got me into trig and pre-calculus.

Later on, I upgraded to a bamboo K&E which I used well into college (mid-80s). Unfortunately it was stolen from my car shortly after I graduated, along with my HP41CV.

Pilots know how to use slide rules. (5, Informative)

fiid (4432) | more than 6 years ago | (#20784657)

The E6-B is a rotary slide rule that pilots use for calculating wind correction angles, time/speed/distance problems, conversion between units (i.e. weight of a certain number of gallons of fuel), and fuel consumption.

It's preferred over digital devices because they still work when the batteries go flat, they are easy to use with one hand, and some models are actually smaller.

http://en.wikipedia.org/wiki/E6B [wikipedia.org]

Dating for Slide Rule Help (1)

The Assistant (1162547) | more than 6 years ago | (#20784709)


  • Go to an online dating service.
  • Add needs to know how to use slide rule as requirement
  • Go on date with EVERY response
  • Learn how to use slide rule

It's THAT easy!!!!

Still have one. (1)

Hans Lehmann (571625) | more than 6 years ago | (#20784711)

I'm 49 years old; In high school my math teachers still had 6 foot long slide rules hanging above the blackboard, but by the time I graduated I was the proud owner of a TI calculator. Within that 2 year (or so) span, pretty much everyone I knew made the jump from only using slide rules to only using calculators. I still, however, have my Kueffel & Esser, made of bamboo, ivory & glass

I'm sorry, but the battery on mine ran out (1)

WillAffleckUW (858324) | more than 6 years ago | (#20784719)

And I just don't have any more pine resin to fill it with.

All the best scientists use wooden slide rules, not those fancy plastic ones. ...

where to find a real one (1)

phrostie (121428) | more than 6 years ago | (#20784725)

i was given one years ago, but somewhere along the way it was lost. does anyone know where to buy one?

it'd be a cool thing to have.

First I saw... (0)

Anonymous Coward | more than 6 years ago | (#20784727)

Was xcalc -analog. I think the analog option is long gone now, though.

In case of... (1)

gregoryb (306233) | more than 6 years ago | (#20784737)

That reminds me of my favorite engineering prof in college. He had his slide rule mounted in a glass case above his desk. Below the case was a hammer and a sign that read "In case of power failure, break glass."

Ok, back to work.

I feel bad (5, Interesting)

planckscale (579258) | more than 6 years ago | (#20784747)

My dad gave me his when I was a teen and said that he had used it for many years in college and the aerospace industry (Hughes). He gave it to me as a memento, and although he didn't keep it stuffed in his ass in Vietnam, it did carry a pretty significant sentimental value. It's lost; and although I did try to use it on several occasions, I only go so far as multiplication. It was a nice ivory color and had a leather carrying case. That thing probably helped launch 20 communication satellites.

The Good Old Days (1)

OldChemist (978484) | more than 6 years ago | (#20784783)

Nice to hear that people still find slide-rules useful in certain applications nowadays. However... A slide rule is good (or better WAS good) for introductory chemistry and physics classes because it forced you to keep track of the exponents for the calculation. That way you didn't (usually) get the ridiculous answers that people sometimes report who are addicted to calculators. But a modern calculator is a God-send for complicated problems that involve lengthy calculations. These are very easy to mess up with a slide rule. With a calculator you can usually do the calculation, twice, much faster than you could with a slide-rule. Generally if your two calcs agree you probably haven't screwed up anything. So far no one seems to have mentioned "circular" slide rules that had certain advantages in that the answer never ran off the end... OC

Mildot Master (4, Insightful)

dazedNconfuzed (154242) | more than 6 years ago | (#20784791)

Slide rules are still in active use by - of all people - snipers. The Mildot Master [mildot.com] is a sliderule for determining distances and ballistics for long-range precision shooting when using a rifle scope fitted with a "mildot reticle".

Simple, low-tech, durable and cheap - specialized slide rules are still useful for particular applications where computers are expensive & fragile overkill.

Never again (1)

John Jorsett (171560) | more than 6 years ago | (#20784817)

I guess everything comes back, but only for people who didn't experience it the first time. Calculators became affordable (barely) when I was in engineering school. I entered with a slide rule and graduated with an HP-45 calculator. While I still have my old slide rule (which was my dad's before me) for sentimental reasons, there's no way I'd ever want to use it again. I couldn't wait to get my hands on a calculator in school, and paid what would be over $1000 in today's dollars, which was an enormous amount of money for a poor college student. I think my monthly rent back then was $140 for the house I was living in.

Get off my lawn you kids.

When I was in school... (1)

ibn_khaldun (814417) | more than 6 years ago | (#20784883)

we used cuneiform on clay tablets. And the sexagesimal numbering system (base-60, but meanwhile cue puns...). Decimal is for wimps. You insensitive clods.

I used to know all that stuff.... (1)

mysticgoat (582871) | more than 6 years ago | (#20784893)

The sliderule was essential to my Dad's work, back in the day. He used it heavily in the thermodynamics engineering of jet engine parts, and later when working on the design of the Apollo heat shield.

A good sliderule in the 1950s was ivory laminated on teak, ebony, or lignum vitae, with a magnifying hairline cursor. The wood was selected for stability despite changes in humidity: ideally it would never warp, crack, expand or contract. The ivory surface was needed for the fine, closely calibrated lines critical to accuracy. The cursors were real hairs: stretched and sealed under optical quality glass lenses in a carrier designed and built with the same tolerances as a Swiss watch. A good sliderule cost several hundred dollars at the time: the equivalent cost today would be more than most desktop computers.

I learned to do basic sliderule operations before high school. Fortunately for me, the first four function calculators arrived on the scene before I faced any critical need for arithmetic. Those were the clunky, heavy things with red displays that could eat up a couple of nine volt batteries in a day's work. But that's another story.

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