HP-35 anniversary marks 40 years since the end of the slide rule

[gary]

Today marks the 40th anniversary of the release of the Hewlett-Packard HP-35
calculator, which took place 1 February 1972.

The first handheld scientific calculator, it included trigonometric and logarithmic functions.
Bill Hewlett himself had challenged his engineers to build it small enough so that it could
fit in a shirt pocket.

The story goes, it was designated the HP-35 because it had 35 keys.

It was an instant success and its introduction heralded the end
of the slide rule as the engineer or scientist's personal, portable calculating
device of choice.

Slide rules had reached their design high point just before the HP-35's release
with instruments such as this Faber-Castell Novo-Duplex.
See http://sliderulemuseum.com/Faber/S12...tell_2-83N.jpg
I still have one somewhere.

To read more about the HP-35's history and development, follow the links on this page here -
http://www.hp.com/hpinfo/abouthp/his...lsystems/0023/

When one considers that we were using plastic slide rules 40 years ago,
it gives reason to pause and wonder what people's personal computing requirements
will be like in another 40 years from now.

[Jeffkop (Jeff)]

Still have my old slide rule AND the hanimex calculator (1975 vintage) that replaced it. Well sort of replaced it .. we werent allowed to use calculators at school HAHAHAHAHA !!!!
http://www.vintagecalculators.com/HanimexBC900_1.jpg

IT was amazing how accurate a slide rule could be IF you knew how to use it .. 2 decimal places was a breeze and even with a bit of parrallex error

[bojan]

Yes, slide rule...
I still know how to use it (I think I do, that is..)

At those (good) old days, I was capable to do the mental calculations by manipulating the image of the slide rule in my mind, down to 20-25% accuracy - enough for initial estimation of the results (try to do it with digital calculator !!) .. Ahhh, where were those times gone...

[Baddad (Marty)]

I remember seeing my first 4 function calculater about 1973. It cost almost a month's pay.
Now a computer costs less than that.
I used to own an HP. with the red led readout. I was truly amazed at the number of significant figures it was capable of.

Cheers

[Omaroo (Chris Malikoff)]

Thanks for this Gary - great post.

I went through my final year of high school with my trusty HP-32E, and have never been able to calculate algebraically since. Instead, RPN logic is just so...well.. logical.

Thanks to Bert (Avandonk) and H0ughy here on IIS, my HP calculator collection has a few newer additions. This is part of my collection - those that work brilliantly still and can be used day to day. The rest still in the process of being re-built or fixed, and as soon as I have time I'll get them all working (hopefully) and into a glass cabinet.

Left to right are: HP-33E, HP-33C, HP-32E, HP-35, HP-12C, HP-41CV, HP-41CV, HP-38G and a Russian MK-61 from Elektronika - a functional early example of RPN calculatorness from behind the Iron Curtain. Awful keyboard I might add. I'd be double-checking every input. LOL

On its own is the HP-35 that Bert kindly donated - after a complete rebuild. It now works very well indeed.

LOVE my HP's!

Lastly - my current HP-35s which was released in 2007 to commemorate the 35th anniversary of the original HP-35. I use this now every day, and it's great calculator in its own right - it also brought back that familiar tactile firm but soft click in the keyboard that made the original HP's so much nicer to use than any Texas Instruments thingamajig at the time. It also brings back the old trapezoidal key face that supports four (and some five) functions (yellow, blue and alpha) per key. Very nice

[bojan]

BTW...
I used to have one of those back in '68 (no idea where it is now.. but then it was very handy):

[Barrykgerdes]

Originally Posted by gary

Today marks the 40th anniversary of the release of the Hewlett-Packard HP-35
calculator, which took place 1 February 1972.

The first handheld scientific calculator, it included trigonometric and logarithmic functions.
Bill Hewlett himself had challenged his engineers to build it small enough so that it could
fit in a shirt pocket.

The story goes, it was designated the HP-35 because it had 35 keys.

It was an instant success and its introduction heralded the end
of the slide rule as the engineer or scientist's personal, portable calculating
device of choice.

Slide rules had reached their design high point just before the HP-35's release
with instruments such as this Faber-Castell Novo-Duplex.
See http://sliderulemuseum.com/Faber/S12...tell_2-83N.jpg
I still have one somewhere.

To read more about the HP-35's history and development, follow the links on this page here -
http://www.hp.com/hpinfo/abouthp/his...lsystems/0023/

When one considers that we were using plastic slide rules 40 years ago,
it gives reason to pause and wonder what people's personal computing requirements
will be like in another 40 years from now.

Hi Gary
Yes I bought a HP35 in 1972. I got a special price as a student but even then it cost a lot of money.

The first real work I used it for was polar/cartesian conversions. I loved that reverse polish notation.

I loaned it to my son when I was in the UK 1976-78. I haven't seen it since.

I have now had to revert to my Faber-Castell slide rule, another student special from 1968, for quick calcs. I wonder how many youngsters can use a slide rule, or even maths tables from school days.

By the way do you remember any of those un-documented key combinations to display odd bits of useless data. and shelloil 71011345

Barry

[GeoffW1 (Geoff)]

Hi,

Yes, similar memories, I still have my Sun-Hemmi slide rule, in case with instruction book. And, a Chambers' 7 figure log tables !

I shied away from RPN and stuck with a conventional Texas Instruments SR-52. It eventually failed, and I repaired it with a blob of solder on the printed board. I wish now I'd kept it. It was a revelation in 1976 and cost an absolute fortune then.

Haha I think shelloil was one of the things the slick salesman showed me.

Cheers

[avandonk]

From memory a HP35 cost about $130 in those early days. At the time my salary was about $50 dollars per week.

As soon as I saw the TLC that Chris gave a HP33E I sent him I looked through all my collection of valuable artefacts or junk as my ex wife used to call it and found the HP35. The picture Chris has put up is nothing like the state the HP35 was in when I rediscovered it. I only had a very vague memory of saving it from the bin many years ago.

I was complaining to myself how long it took to stack/align and statistically average twenty 190MB tiff images with my now 'slow' computer until the thought of doing the same calculations by hand came to mind.

The scientific giants of the past did it all with pencil and paper. Fourier and Laplace are two.

Bert

[Rick Petrie]

Still have my 'hemmi 130' slide rule from my old surveying days.(pictured)
The HP 41C was a godsend in those days to compute all our surveying requirements. With the modern day computers all these old methods were quickly made obsolete and our total procedure from field work, computations, design to final plans was all done on the PC. It makes you wonder where technology is directing us????
Great post Gary.

[lepton3 (Ivan)]

Not as old as some here, but I was on the tail of slide rule / log tables use in High School. We still had to do mental arithmetic, and learn stuff like cos(30) = sqrt(3)/2.

Nowadays I see fresh engineers having trouble with dBs because they have limited feel for logs. Of course, all of that stuff is irrelevant to what is important today (i.e. facebook).

I bought my first HP calculator in 1983, a 15-C, for my engineering studies. The complex arithmetic and matrix inversion functions were a godsend in electronics engineering. The numerical integration function also saved me a couple of times in physics experiments.

My current workhorse is a 35-S. Having used a HP calculator from the start, I find it incredibly tedious to use a "normal" calculator. The stack works so well, keeping the results of intermediate calculations hanging around for when they are needed later.

-Ivan

[wavelandscott (Scott)]

I am glad you posted...you post such interesting stuff!

I caught the tail end of the slide rule era in High School...we could use a slide rule but not a calculator (not that anyone in class could afford one anyway).

You have inspired me to look for mine again. The first calculator we had on the farm was a Texas Instrument I can not remeber the model. My brothers and I were not allowed to touch it.

[ballaratdragons (Ken)]

Wow, memories!

I remember having to buy a thing called a 'Calculator' in my first year of Technical School in 1972 (remember Tech schools?).
I went to Blacktown Technical School as an apprentice Electrician.

It was nothing like those flashy HP-35's. It only did: add, subtract, multiply, and divide.
It cost my parents $80 and Dad was only getting about $80 a fortnight pay in the Air Force!!!

It looked exactly like this model but it might have been a different brand. Could've been Casio or Hanimex:

[strongmanmike (Michael)]

Originally Posted by gary

Today marks the 40th anniversary of the release of the Hewlett-Packard HP-35 calculator, which took place 1 February 1972.

Well fancy that, that was a Tuesday and was probably the first day of school for me, I started kindergarten (K1 at Belair Primary in Newcastle) at just 4 years and 9 months old

Time marches on and stops for no one......

Cool thread

Mike

[Paul Haese]

I had a HP25 at school (year 11) and then one in the Army for survey work. I later got a 11c which I regretably sold while at Uni in the 90's. I vaguely remember using a slide rule in the late 70s, but love the reverse polish notation of the HP calculators. Trip down memory lane.

[gary]

Thanks to everyone who made contributions to this thread including for
your shared reminiscences and wonderful pictures of slide rules and calculators.

Chris, I was aware from a previous thread that you had a collection and thanks for
sharing the picture of it. Wow! It looks fantastic!!!

Special thanks goes to HOughy and to Bert for their contributions to Chris's collection
and the crowning piece would surely have to be the HP-35 that Bert provided.
That is a piece of history.

Bert was trying to recollect the price for the HP-35 and one reference I found on the net
suggested US$395 when it was introduced in 1972 and US$195 when it ended
production in 1975. Relative to wages, they certainly were very expensive at the
time.

In that regard this quote from the HP web site is telling -

HP asked a local market research firm to do a market study. They did and determined that the HP-35 Scientific Calculator would never sell because it was too expensive. Bill said "We're going to go ahead anyway." The product was so popular that HP couldn't make them fast enough.

As is the quote from one of the HP PDF files where it says -

The initial goals set for its design were to build a shirt-pocket-calculator with four-hour
operation from rechargeable batteries at a cost any laboratory and many individuals
could easily justify.

"Any laboratory and many individuals could easily justify"!
You can picture scientists in the lab back in 1972 asking, "May I borrow the
HP-35 calculator today?"

Apparently the HP-35 had a grand total of 768 bytes of ROM and 49 bytes of
RAM but they managed to microcode everything into it, including the trigonometric,
logarithmic and exponential functions using iterative algorithms "first described
by Henry Briggs in 1624". So where Barry mentioned the giants of the past
doing everything with pen and paper, I think they would be pleased if they
could possibly have known how many of the techniques they devised would
be used in such advanced technology 350 years later.

Barry gave me a laugh when he reminded me of "ShELLOILL". It has been while
since I thought of that. Thank you!

On the HP-45, which was the successor to the HP-35, there was a hidden stop-watch
function that was officially undocumented but you could invoke by a special combination
of button presses. Alas, it was not accurately crystal controlled so its time
scale did not correspond to the normal time scale.

Paul mentioned owning a HP-25 and it was a wonderful calculator that gave
many of us our first opportunity at hands-on programming. It had 49 steps
of program memory and the most wonderful instruction manual along with
a separate book of programs. The Lunar Lander Game where one had to try and gently
touch-down the lunar module on the surface with a fuel budget idled away many
a spare moment.

Ivan mentioned the HP-15C which personally is the nicest calculator I have
ever used. I have owned one since its introduction and still use it nearly every
day. I particularly love the ergonomics of its case which you hold in "landscape
mode". This was an electrical engineer's dream calculator. Electrical engineering
is one of those rare professions that actually find complex number
arithmetic (i.e. that square root of minus stuff) incredibly useful.
Ivan mentioned the in-built integrate function but I have distinct memories of the
HP-15c's ability to handle complex number arithmetic and its inbuilt root
solving function called "Solve" allowing me to pass the "Systems and Controls II"
exam when having to do something like a Nyquist plot where you had to
solve complex polynomials. The alternative to doing it by hand would see
you filling multiple exam books with equations but the HP-15C allowed you to
enter the polynomial as a program and then just hit SOLVE.

When HP released a Limited Edition release of the HP-15C late last year,
I grabbed two. Now we have three HP-15c's in all. The original and a new
one we use everyday and we kept a new one in the box as the "emergency backup".

Thanks again to everyone for the memories. Every byte was a joy to read.

[matteo munari (Matteo)]

i have a couple of them if anyone is still interested

http://www.flickr.com/photos/2901947...57609195920064