Re: [GTALUG] Chromebook death dates

[Dave Collier-Brown via talk]

When I was a motorcycle mechanic I had a circular slide rule, with a
permanent mark at the coefficient for computing a catenoid, as I did a
lot of 2-stroke exhaust systems. Some hilariously wrong, some which got
me a reputation as a wizard.

--dave

On 6/1/23 18:08, D. Hugh Redelmeier via talk wrote:

| From: Scott Allen via talk 

| I thought the circular ones were an interesting idea but I only had a
| cheap plastic straight one.
| https://www.sliderule.tokyo/products/detail.php?product_id=8

Yeah, I had a cheap one from Coles Book Store discount bin.

With a regular slide rule, you had to realize when to wrap around:
5 x 5 would go off the right end so you had to go left to 2.5 (and
to increment the in your head expoent).  With the circular slide rule, the
wrapping was automatic but you still had to increment the exponent.

One of our classrooms had a very large demo slide rule.  7'?  It was
yellow so I think that it was a Pickett

That should have given 4 digits of accuracy

A colleague in the Computing Centre at Waterloo showed me a helical slide
rule.  It must have been something like this:
http://retrocalculators.com/otis-king.htm
The result is an extra digit of accuracy without being too large

| The year after I learned "slide rule" in high school, training was
| dropped because calculators were becoming the norm.

Every new techology begets grumbles about what was lost.

- analogue leads to elegant, precise, timeless devices

- a slide rule forces you to have a feel for the answer.  At a minimum,
   the power of 10.

- a 10-digit answer from a calculator makes you think you have the 10
   digit answer.  Almost nothing you measure (as opposed to count) has that
   much accuracy.

Me?  I like discrete problems.  Perect for digital computers.  I have
calculated precise and accurate numbers that are thousands of digits long.

Of course some have calculated millions of digits of the decimal
representation of Pi.  Not with a slide rule.
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--
David Collier-Brown, | Always do right. This will gratify
System Programmer and Author | some people and astonish the rest
dave.collier-br...@indexexchange.com |  -- Mark Twain


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Re: [GTALUG] Chromebook death dates

[D. Hugh Redelmeier via talk]

| From: Scott Allen via talk 

| I thought the circular ones were an interesting idea but I only had a
| cheap plastic straight one.
| https://www.sliderule.tokyo/products/detail.php?product_id=8

Yeah, I had a cheap one from Coles Book Store discount bin.

With a regular slide rule, you had to realize when to wrap around:
5 x 5 would go off the right end so you had to go left to 2.5 (and 
to increment the in your head expoent).  With the circular slide rule, the 
wrapping was automatic but you still had to increment the exponent.

One of our classrooms had a very large demo slide rule.  7'?  It was 
yellow so I think that it was a Pickett

That should have given 4 digits of accuracy

A colleague in the Computing Centre at Waterloo showed me a helical slide 
rule.  It must have been something like this:
http://retrocalculators.com/otis-king.htm
The result is an extra digit of accuracy without being too large

| The year after I learned "slide rule" in high school, training was
| dropped because calculators were becoming the norm.

Every new techology begets grumbles about what was lost.

- analogue leads to elegant, precise, timeless devices

- a slide rule forces you to have a feel for the answer.  At a minimum, 
  the power of 10.

- a 10-digit answer from a calculator makes you think you have the 10 
  digit answer.  Almost nothing you measure (as opposed to count) has that 
  much accuracy.

Me?  I like discrete problems.  Perect for digital computers.  I have 
calculated precise and accurate numbers that are thousands of digits long.

Of course some have calculated millions of digits of the decimal 
representation of Pi.  Not with a slide rule.
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Re: [GTALUG] Chromebook death dates

[James Knott via talk]

On 2023-06-01 15:30, James Knott wrote:
I still have the 2nd one.  It's a Sharp EL-545, which also still 
works.  I guess it's pushing 25 years old or so and it also still 
works.  It came with a thick instruction book.


Correction, 35 years.

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Re: [GTALUG] Chromebook death dates

[James Knott via talk]

On 2023-06-01 12:32, James Knott wrote:
then a couple of Sharp calculators, the first of which used batteries 
and the 2nd light powered.


I still have the 2nd one.  It's a Sharp EL-545, which also still works.  
I guess it's pushing 25 years old or so and it also still works.  It 
came with a thick instruction book.


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Re: [GTALUG] Chromebook death dates

[Scott Allen via talk]

On Thu, 1 Jun 2023 at 15:05, D. Hugh Redelmeier via talk
 wrote:
> Pickett was a good brand.  I really didn't like plastic slide rules
> because they were jerky to operate: stiction.

I thought the circular ones were an interesting idea but I only had a
cheap plastic straight one.
https://www.sliderule.tokyo/products/detail.php?product_id=8

The year after I learned "slide rule" in high school, training was
dropped because calculators were becoming the norm.

-- 
Scott
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Re: [GTALUG] Chromebook death dates

[James Knott via talk]

On 2023-06-01 15:05, D. Hugh Redelmeier via talk wrote:

I remember seeing the initial ad campaign.  A big price drop from other
calculators.  But it only had 4 functions.  I had been given a scientific
calculator by then, if I remember correctly.  Oddity: floating point but
no scientific notation -- crazy.


Yep, it was a 4 banger.  Fixed point at 2 digits.  It also took a fair 
effort to press the keys, IIRC.  A couple of years later, I bought a 
couple of their desktop calculators, from a surplus place in the 
states.  SD Sales?  Even though they were made in Toronto, I still had 
to pay duty to bring them across the border.




| BTW, as I mentioned the other day, I still have a slide rule from my high
| school days.  It's a Pickett Microline 120 and it still works 56 years later!
| By the time I got to Ryerson, I was using a calculator.



Pickett was a good brand.  I really didn't like plastic slide rules
because they were jerky to operate: stiction.




Well, what do you expect for $2?  
Anyway, I was just a kid starting high school at the time. Incidentally, 
there's a bit of a story about my first day in electricity class, which 
is what I bought that slide rule for.  On the first day of class, the 
teacher was talking about resistance and how all conductors had it.  I 
then asked "What about superconductors?".  He'd never heard of them 
(this was Sept. 1967, when few people had).  I knew about them, because 
I had read about them in an encyclopedia that I had at home.  So, the 
next day, I brought in that volume to show him.  IIRC, superconductivity 
was discovered by a German physicist in 1914, when he inserted lead wire 
in liquid helium.


My grade 12 electronics teacher had a big, multi-scale slide rule, which 
could handle reactance (capacitance & inductance) directly.


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Re: [GTALUG] Chromebook death dates

[D. Hugh Redelmeier via talk]

| From: James Knott via talk 

| My first calculator was a Rapidman 800, which sold for about $100 at Eaton's,
| IIRC.


Interesting vignette:


I remember seeing the initial ad campaign.  A big price drop from other 
calculators.  But it only had 4 functions.  I had been given a scientific 
calculator by then, if I remember correctly.  Oddity: floating point but 
no scientific notation -- crazy.

| BTW, as I mentioned the other day, I still have a slide rule from my high
| school days.  It's a Pickett Microline 120 and it still works 56 years later! 
| By the time I got to Ryerson, I was using a calculator.



Pickett was a good brand.  I really didn't like plastic slide rules 
because they were jerky to operate: stiction.

Some fancy Pickets were supposedly made from magnesium to avoid this 


I liked Sun Hemmi slide rules because they were made of bamboo.  I still 
have one somewhere.  Or maybe two.
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Re: [GTALUG] Chromebook death dates

[James Knott via talk]

On 2023-06-01 12:22, D. Hugh Redelmeier via talk wrote:

I loved calculators but I actually rarely need them.  I've stopped
buying them.  But not before I bought too many.

The first calculator I bought was a used Sinclair.  You, Stewart, will
know of those.  Amazing but very cheaply built.  It didn't last and I
no longer have it.


My first calculator was a Rapidman 800, which sold for about $100 at 
Eaton's, IIRC.  My next one was a Novus Mathematician, which used RPN 
and then a couple of Sharp calculators, the first of which used 
batteries and the 2nd light powered.  These days, I use an Android app 
called RealCalc.


BTW, as I mentioned the other day, I still have a slide rule from my 
high school days.  It's a Pickett Microline 120 and it still works 56 
years later!  By the time I got to Ryerson, I was using a calculator.


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Re: [GTALUG] Chromebook death dates

[D. Hugh Redelmeier via talk]

| From: Stewart C. Russell via talk 

| Easier said than done. Remember that the entire HS maths curriculum in the US
| is effectively owned by TI calculators, and their lock-in allows them to sell
| a 1980s-tech 'approved' calculator for ~$100.

Aren't "moats" great (Warren Buffet's term, I think)!

| Compare this to the $1 scientific calculators you can get in dollar stores
| (and supermarkets near "back to school" time). These are perfectly adequate,
| but not "approved". A retired academic friend, ex CalTech, introduced me to
| these super cheap calculators. He's done a whole suite of accuracy benchmarks
| on a number of models, and they come out as well as the market leaders.

Old geezer mode:

I remember in the 1970's attending a couple of talks at U of T by
Velvel Kahan about floating point accuracy.  Always amazing and hair
raising.  One was about calculator accuracy.

,  a very notable numerical 
analyst.

- a key architect of IEEE floating point

- moved to UC Berkeley before I got to U of T.  But he still had
  colleagues there.  Notably T. E. Hull who I studied with.

- showed that IBM SYSTEM/360 floating point had disastrous loss of 
  accuracy due to base-16 quantization.  At his suggestion, IBM fixed this 
  (mostly) by adding a "guard digit".  This entailed physically upgrading 
  each machine already in the field!  It also halved the performance of 
  some machines because their FP ALUs weren't wide enough for the new 
  requirement.

- developed the program "paranoia" to test for bugs in IEEE FP
  implementations

In that talk, he showed that all calculators made bozo errors, many
unique to a calculator.  As a consultant to Victor, he got their
errors fixed.  I don't remember whether HP and TI listened to him.

This makes me very wary of random-brand calculators.

(I've taken at least three Numerical Analysis course.  My main take-awy is 
that getting FP right is really hard.  Naive calculations are often wrong 
with no hints of problems.)



I loved calculators but I actually rarely need them.  I've stopped
buying them.  But not before I bought too many.

The first calculator I bought was a used Sinclair.  You, Stewart, will
know of those.  Amazing but very cheaply built.  It didn't last and I
no longer have it.



The next was a Commodore (later known for the PET, the Commodore-64
and the Amiga).  Something like this:

The weird mushy keys showed up again in the PET keyboard.

The most recent (years ago): Dollarama sold nice Sharp D.A.L calculators for 
$2.99.

While I was buying and not using cheap calculators, by cubicle-mate
Henry Spencer was buying and open-carrying fancy HP ones.  I got a
couple of cast-offs and they were wonderful, but still not useful.

I got a Sharp calculator out for tax time this year, but it just
wasn't what I needed.  I used bc(1) and LibeOffice Calc instead.  Neither
was quite what I wanted but they were good enough.  Maybe a Mathematica
notebook or something like that wuld be better (I've never used that).
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