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HP-15C - useless today?
Message #1 Posted by Reth on 5 Dec 2011, 2:08 a.m.

After playing a bit with the HP-15C LE (keyboard fixed) I'm under the impression, that apart of nostalgic reasons it is no worth getting it at all. Its low internal accuracy makes it hopeless and also makes HP-35S look acceptable. Both can't compare with the BRILLIANT Free 42S by Thomas Okken and more so with Byron Foster's implementation for iPhone. I wander who would use it today for real work?

      
Re: HP-15C - useless today?
Message #2 Posted by Les Wright on 5 Dec 2011, 3:16 a.m.,
in response to message #1 by Reth

I am glad I have one as a collector, and I use it more than the near-mint 1985 version I paid too much for and am afraid to look at funny. But since I discovered wp34s and how easy it is to flash a calc and assemble and disassemble programs, I just don't pay much attention to it these days. Indeed, Samson has its back-ordered HP15C LEs marked up 50 %, but the 30b is priced to clear at 30 bucks. I just ordered another of the latter to perpetuate my wp34s fascination :D.

Les

      
Re: HP-15C - useless today?
Message #3 Posted by From Hong Kong on 5 Dec 2011, 3:46 a.m.,
in response to message #1 by Reth

Quote:
After playing a bit with the HP-15C LE (keyboard fixed) I'm under the impression, that apart of nostalgic reasons it is no worth getting it at all. Its low internal accuracy makes it hopeless and also makes HP-35S look acceptable. Both can't compare with the BRILLIANT Free 42S by Thomas Okken and more so with Byron Foster's implementation for iPhone. I wander who would use it today for real work?


It depends on where you use it. I think only rocket science needs a higher internal accuracy. In such case, you might need a sophisticated computer rather than a calculator.

            
Re: HP-15C - useless today?
Message #4 Posted by Reth on 5 Dec 2011, 5:18 a.m.,
in response to message #3 by From Hong Kong

Quote:
... only rocket science needs a higher internal accuracy...

Not at all.

In the case of a rope looped around the Earth, what clearance would provide 1m extension if the rope were lifted? Try to solve this on 15c or 35s. Piece of cake for the 42s.

                  
Re: HP-15C - useless today?
Message #5 Posted by Thomas Radtke on 5 Dec 2011, 5:42 a.m.,
in response to message #4 by Reth

Quote:
In the case of a rope looped around the Earth, what clearance would provide 1m extension if the rope were lifted?
About 15cm ;-).
                  
Re: HP-15C - useless today?
Message #6 Posted by Paul Dale on 5 Dec 2011, 5:49 a.m.,
in response to message #4 by Reth

Simplicity itself even on a four banger.

The answer doesn't depend on the radius of the circle the loop forms so the big numbers completely disappear. A tiny bit of algebra before hand makes easy work of this :-)

- Pauli

PS: about 0.159154943091895m

                        
Re: HP-15C - useless today?
Message #7 Posted by Crawl on 5 Dec 2011, 9:20 a.m.,
in response to message #6 by Paul Dale

I think he's asking this question, not if the rope was hovering uniformly in space over the entire earth.

                              
Re: HP-15C - useless today?
Message #8 Posted by Crawl on 5 Dec 2011, 9:36 a.m.,
in response to message #7 by Crawl

Not that that's something that should be impossible for the HP15c, either.

Taking the Taylor series, you get the answer is

R/8*(12x/R)^(2/3)

This gives 121.6440...

whereas solving the equations exactly (which you can almost certainly also do with the HP15C, though I don't have mine with me now) gives

121.6447...

                                    
Re: HP-15C - useless today?
Message #9 Posted by Jeff Kearns on 5 Dec 2011, 1:59 p.m.,
in response to message #8 by Crawl

Valentin's 'original' answer is as follows.

Quote:

"A little geometry will duly solve this. Let's call the Earth's radius r, the subtended angle between the point of maximum height and the point of tangency we'll call x, and let's say the length of the cable not in contact with the Earth is 2a. The corresponding circular arc length is 2rx. Let d be the extra length added to the cable. Then 2a = 2rx + d. Hence a = rx + d/2, and so a/r = x + d/2r.

We also have, tan(x) = a/r. Therefore the equation to solve for the angle x is:

tan(x) = x + d/2r

Once we've got the angle x by solving it, we then have that the required height h over the ground is:

h = r(sec(x) - 1)

For our particular problem d = 1, r = 6,400,000, so we must solve:

tan(x) = x + d/2r = x + 1/12,800,000

which gives:

x = 0.00616549902401 radians

and from this, the height h is:

h = r(sec(x) - 1) = 6,400,000*(sec(0.00616549902401) - 1) = 121.644736 m

If the man can stretch his arm to a height in excess of 120 m (360 feet) while comfortably sitting at ground level, he must be Mr. Reed Richards, alias "Mr. Fantastic", so his brother-in-law's name should be Johnny Storm, alias "The Human Torch", both members of the well-known Fantastic Four superhero team.

This is my 20-step program for the HP-15C which will return the height for any given extra length. First store the constant 12,800,000 (2r) in R0 and set RAD mode:

01 LBL A 02 STO1 03 0 04 SOLVE B 05 COS 06 1/X 07 1 08 - 09 RCL*0 10 2 11 / 12 RTN 13 LBL B 14 TAN 15 LASTX 16 - 17 RCL 1 18 RCL/0 19 - 20 RTN

Running it, we can get for instance:

For d = 1 m: 1 GSB A -> 121.6448 m (h) d = 0.1 m: 0.1 GSB A -> 26.2080 m d = 10 m: 10 GSB A -> 564.6400 m

As you may see, even a mere 0.1 meter (some 4 inches) of extra length can raise the highest point to a height of more than 26 meters (nearly 80 feet). Mr Fantastic would still be needed."

The 15C is more than up to the task and is neither useless nor obsolete. It was my 'main' calculation tool in a mechanical engineering program in the 1980s and would still serve as such today.

Jeff Kearns

Edited: 5 Dec 2011, 2:08 p.m.

                                          
Re: HP-15C - useless today? Not anymore!
Message #10 Posted by Reth on 5 Dec 2011, 3:19 p.m.,
in response to message #9 by Jeff Kearns

Thanks a lot, Jeff, that's exactly what I was after. And I found what I did wrong using the solver. I take my words back!

It's not for sale (yet) ;)

                  
Re: HP-15C - useless today?
Message #11 Posted by Martin Pinckney on 5 Dec 2011, 9:34 a.m.,
in response to message #4 by Reth

Quote:
Not at all.

In the case of a rope looped around the Earth...


This is a real problem? Or was this offered tongue-in-cheek? While I'm not a 15c nerd, it's nonsense to say that it's 10-digit accuracy is inadequate for practical problems that a hand-held is meant to solve.
                  
Re: HP-15C - useless today?
Message #12 Posted by Mark Storkamp on 5 Dec 2011, 9:39 a.m.,
in response to message #4 by Reth

And does the 42 take into account thermal expansion and contraction for the sides in sun or shade? What about tension and elasticity? The 15C is just fine for REAL problems, maybe not so much for the made up variety.

      
Re: HP-15C - useless today?
Message #13 Posted by Frido Bohn on 5 Dec 2011, 4:03 a.m.,
in response to message #1 by Reth

For real work I would use a computer.
For doing maths I would use then either a CAS software, program routines myself or even take a spreadsheet application.
As long as I have a computer within reach I would prefer it over any calculator.

There may arise situations where the use of a computer is impractical. May be then somewhere in the field or somewhere without electricity.
In such cases a device would be advisable with an optimum between versatility and battery life. This would be not a smartphone, I guess.

For me, the main impulse to be engaged with the nostalgia calculators is that there is easily accessible expert knowledge about them. Nowadays, dozens of years after they were introduced, there is countless material about them so one can gather in-depth knowledge about their innards on hardware and software basis. A crucial point for me is that those old calculators have a history: they have an accomplished biography documented in countless periodicals or newsletters. A whole generation was deeply involved with them - and of course, still is.
The impact these calculators had on their lives will be barely seen with modern devices which are too transient and interchangeable, although their capacity may be more advanced in some orders of magnitude. I simply can't imagine that we will have such a huge community who cares about TI-Nspire or HP-50g in 30 years.

            
Re: HP-15C - useless today?
Message #14 Posted by Thomas Radtke on 5 Dec 2011, 5:04 a.m.,
in response to message #13 by Frido Bohn

Quote:
For doing maths I would use then either a CAS software [...]
Interesting. In SpaceTime 3 and 4, calculating Eigenvalues fail using built in numerical routines on certain PDAs (s. discussion in the respective ST forum). The pure CAS solution works, however. Trust no one except really proven systems like..? The 15C? ;-)

This calculator is not useless and not obsolete. But there are people who have no use for it or *find* it obsolete. There's a difference.

                  
Re: HP-15C - useless today?
Message #15 Posted by Reth on 5 Dec 2011, 5:23 a.m.,
in response to message #14 by Thomas Radtke

Quote:
This calculator is not useless and not obsolete.
Because of: ...??? Or just because you think so.
                        
Re: HP-15C - useless today?
Message #16 Posted by Thomas Radtke on 5 Dec 2011, 5:31 a.m.,
in response to message #15 by Reth

Quote:
Because of: ...??? Or just because you think so.
I'm using it, so it's useful (to me). I went back from more 'modern' solutions to the 15C, so it's hardly obsolete (to me).
                        
Re: HP-15C - useless today?
Message #17 Posted by Dave on 5 Dec 2011, 4:02 p.m.,
in response to message #15 by Reth

The reason why the 15C is neither useless nor obsolete is that in the 30 years it was out of production, HP failed to make any model equal to it in terms of functionality, form factor and price. Like an idiot, I sold my 15C years ago thinking HP's next model would be better. Well, it wasn't, and neither was the next model or the next. So I'm ecstatic to have a brand new 15C which is just as elegant and useful as it was 30 years ago. Because I have no reason to believe HP will ever make another model as good as the 15C, I bought enough spares to last the rest of my life.

                              
Re: HP-15C - useless today?
Message #18 Posted by Michael de Estrada on 5 Dec 2011, 4:22 p.m.,
in response to message #17 by Dave

Amen.

                              
Re: HP-15C - useless today?
Message #19 Posted by Mike Morrow on 5 Dec 2011, 5:14 p.m.,
in response to message #17 by Dave

Quote:
HP failed to make any model equal to it in terms of functionality, form factor and price.

Nonsense! I've got two 15C and two 15C-LE units, and I've used this model since 1985. However, it does not compare favorably to the 1988 HP 42S in any detail except that the 15C is visually much more attractive. But visual beauty, IMHO, is not enough to trump all the many other aspects in which the 15C is grossly inferior to the later 42S.

                                    
Re: HP-15C - useless today?
Message #20 Posted by Michael de Estrada on 5 Dec 2011, 5:36 p.m.,
in response to message #19 by Mike Morrow

                                          
Re: HP-15C - useless today?
Message #21 Posted by geoff quickfall on 5 Dec 2011, 5:44 p.m.,
in response to message #20 by Michael de Estrada

zing!

                                          
Re: HP-15C - useless today?
Message #22 Posted by Kerem Kapkin (Silicon Valley, CA) on 5 Dec 2011, 6:01 p.m.,
in response to message #20 by Michael de Estrada

LOL !

                                    
Re: HP-15C - useless today?
Message #23 Posted by Dave on 5 Dec 2011, 9:27 p.m.,
in response to message #19 by Mike Morrow

Apples and oranges. The 42S did not replace the 15C. It replaced the 41. The 32S replaced the 15C, and it was less functional, as was the 32Sii, 33S and 35S. There are plenty of HP calcs that do a lot more than the 15C and 42S, but none have the trifecta I posted.

                                          
Re: HP-15C - useless today?
Message #24 Posted by Bill Platt on 5 Dec 2011, 10:09 p.m.,
in response to message #23 by Dave

I disagree with you (on this sort of absurd academic point).

I feel that the 32s replaced the 11c, the 42s replaced the 15c with the ability to use 41 programs.

With no I/O, there was never even the slightest possibility that the 42s could be seen as a replacement for the 41 system. That had to wait for the 28 and then 48 series. In some ways even they didn't do it. Who have you ever heard of using a 48 to do data gathering of multiple HPIL inputs? (Maybe the PC simply came to replace by then...and so I didn't notice?)

Edited: 5 Dec 2011, 10:10 p.m.

                                          
Re: HP-15C - useless today?
Message #25 Posted by Mike Morrow on 6 Dec 2011, 7:04 p.m.,
in response to message #23 by Dave

Quote:
The 42S did not replace the 15C. It replaced the 41. The 32S replaced the 15C, and it was less functional, as was the 32Sii, 33S and 35S.

One should not just "make up" the history and the development of HP calculators. Those familiar with HP calculators can cite real facts to show that the above statements are baseless in every particular.

In absolutely NO informed appraisal can the HP 42S be considered a replacement for the HP 41C series. It was designed to be program semi-compatible, but that is all and that does not the 42S a "replacement" for the 41C make.

Many might consider it a somewhat important detail to recall that the HP-41C is, er, expandable, while the 42S is, er, NOT expandable. It is nonsense to claim the keyboard/LCD/printer-only I/O 42S is "the replacement" for a device that can control multiple diverse devices on an HPIL loop, use input from a bar code reader, use a magnetic card reader, employ various other I/O and time modules, and utilize RAM and ROM memory of very many sorts. Exactly how does that "replacement" HP 42S "replace" any of such capabilities, or is that just some small and negligible and inconvenient detail?

Additionally, the 42S itself has many advantages never found in any configuration of the 41C. Its Saturn processor is faster and produces results that have several orders of magnitude better accuracy and precision. The scope of the 42S mathematical function set is far greater than that of the 41C, including exhaustive complex domain support, matrix manipulation, a numerical solver, and a numerical integrator. The 42S is smaller and lighter than the 41C, and operates almost forever on its three 357 cells.

Compare the 41C to the 15C. The scope of the 15C mathematical function set is far greater than that of the 41C, including exhaustive complex domain support, matrix manipulation, a numerical solver, and a numerical integrator. The 15C is smaller and lighter than the 41C, and operates almost forever on its three 357 cells.

Hmmm...one might just conclude that the 42S was the replacement for the 15C, and not the replacement for the 41C. Or someone like me who has been buying HP calculators for 35 years could tell you that no one, neither HP nor customer, ever considered the HP 42S as the replacement for the HP 41C.

With respect to the 32S and the 15C, the 32S/SII isn't close to being a functional replacement for the 15C. Like all Pioneers, there are several improvements over earlier models, such as (1) limited alpha display, (2) greater speed, (3) better accuracy/precision, and (4) portrait rather than landscape keyboard. But anyone who replaced his 15C with the 32S/SII was likely very disappointed after finding that his new calc lacked many of the features and functions of the 15C, not the least being competently-executed complex domain support. I bought a 32SII to replace a 15C in 1997, when the 42S was no longer available from HP. I immediately retired that new but painfully inadequate grade-schooler's calc to storage. Happily, I was shortly thereafter able to obtain three HP 42S units. All of them together are physically incapable of replacing my one 1984 HP-41CX. But I didn't buy the 42S as a replacement for the 41CX. Nobody did.

                                                
Re: HP-15C - useless today?
Message #26 Posted by Dave on 7 Dec 2011, 3:42 p.m.,
in response to message #25 by Mike Morrow

Quote:
One should not just "make up" the history and the development of HP calculators. Those familiar with HP calculators can cite real facts to show that the above statements are baseless in every particular.

In absolutely NO informed appraisal can the HP 42S be considered a replacement for the HP 41C series. It was designed to be program semi-compatible, but that is all and that does not the 42S a "replacement" for the 41C make...


You make an interesting argument, but that doesn't make it true. You are the one making up history (HP42S Wiki). I guess Jake Schwartz makes up HP history too when he writes HERE that "Toward the end of 1988, HP introduced the non-expandable HP42S Pioneer model as a successor to the HP41 series." While it's true the 42S wasn't a very good replacement for the 41, it was indeed released as a replacement nonetheless. The 32S wasn't a very good replacement for the 15C either, but that doesn't change the fact that it was. The 15C and 42S have never been in the same class, so it is unfair to compare them.

The 42S belongs in a museum because it has been far surpassed by later models. The 15C has not, and currently fills a niche no other calculator can fill. Its ultimate successor the 33S, or arguably the 35S, can't do matrices and has very limited complex number support.

So history is on my side. And the 15C still has no equal.

Edited: 7 Dec 2011, 3:46 p.m.

                                                      
Re: HP-15C - useless today?
Message #27 Posted by Don Shepherd on 7 Dec 2011, 4:19 p.m.,
in response to message #26 by Dave

Not that this will stop World War III about to play out on these very pages, but according to Wlodek's book the 42s was, in many ways, a Pioneer replacement of the HP-41 series, but at some stage it was repositioned as a 15c replacement instead.

So maybe you both are right.....and, remember, it's the season of peace.

                                                      
Re: HP-15C - useless today?
Message #28 Posted by M. Joury on 7 Dec 2011, 4:40 p.m.,
in response to message #26 by Dave

Quote:
The 42S belongs in a museum because it has been far surpassed by later models. The 15C has not, and currently fills a niche no other calculator can fill. Its ultimate successor the 33S, or arguably the 35S, can't do matrices and has very limited complex number support.

Huh? I am not going to argue whether the 42S replaced the 15C or the 41C (although I personally always thought if it as a 15C replacement since it filled that niche for me but never replaced my 41) but I really don't understand the above argument.

Are you saying that the 42S is outdated because it has been superseded by newer more powerful calculators and at the same time claiming that the less powerful 15C has not been? What niche does the 15C fill that can't be filled by the 42S (setting aside UI preference for menus vs. overloaded keys). And what exactly has replaced the "far surpassed" 42S as a pure scientific programmable calculator? Sorry, maybe I am misunderstanding what you are trying to say.

Cheers,

-Marwan

                                                            
Re: HP-15C - useless today?
Message #29 Posted by Dave on 8 Dec 2011, 11:21 a.m.,
in response to message #28 by M. Joury

Quote:
Are you saying that the 42S is outdated because it has been superseded by newer more powerful calculators and at the same time claiming that the less powerful 15C has not been? What niche does the 15C fill that can't be filled by the 42S (setting aside UI preference for menus vs. overloaded keys). And what exactly has replaced the "far surpassed" 42S as a pure scientific programmable calculator? Sorry, maybe I am misunderstanding what you are trying to say.

Cheers,

-Marwan


The successors to the 42S far surpassed it with the addition of RPL, CAS, I/O, Display, etc.

But none of the successors of the 15C have as much functionality, i.e., matrices and complex numbers, as I said before.

If you want to argue that the 42S is the successor to the 15C, then fine, it's a far better calculator in every way, as are the 28, 48, 49 and 50. But it's not the successor by any stretch of the imagination. If the 42S did replace the 15C, then where does the 32S and it's successors fit in?

Regardless of your opinion of the family tree, what other model has the same combination of simplicity, pocketability and low price as the 15C? The 42S certainly doesn't, and neither does any other model.

                                                                  
Re: HP-15C - useless today?
Message #30 Posted by bill platt on 8 Dec 2011, 11:57 a.m.,
in response to message #29 by Dave

Dave,

The 32s is the successor to the 11c. Have you ever used an 11c?

If you put the two side by side, if you compare memory, features, etc as well as market position and also what the salespeople were saying in the early 90s, the 32s and 32sii are the 11c replacement--not the 15c.

Also as I said before, the 33s and 35s were developed directly freom the 32sii.

Also as I said before, the feature set in the 42s contains every single feature in the 15c and then some.

Also look at the introduction of the 42s relative to the retirement of the 15c.

If you want to do a detailed look, you can use the museums feature comparison tool (very cool!) and I also recommend perusing Craig's site:

http://www.finseth.com/hpdata/hp42s.php

http://www.finseth.com/hpdata/hp15c.php

http://www.hpmuseum.org/cgi-bin/compare.cgi?calc1=HP-15C&calc2=none&calc3=none&calc4=none&calc5=HP-42S&calc6=none&calc7=none&calc8=none&shade=ON

http://www.hpmuseum.org/cgi-bin/compare.cgi?calc1=HP-11C&calc2=none&calc3=none&calc4=none&calc5=HP-32S&calc6=none&calc7=none&calc8=none&shade=ON

and finally:

http://www.hpmuseum.org/cgi-bin/compare.cgi?calc1=HP-32S&calc2=none&calc3=none&calc4=none&calc5=HP-42S&calc6=none&calc7=none&calc8=none&shade=ON

Edited: 8 Dec 2011, 12:03 p.m.

                                                                  
Re: HP-15C - useless today?
Message #31 Posted by M. Joury on 8 Dec 2011, 1:29 p.m.,
in response to message #29 by Dave

I see what you are saying but it doesn't fly with me. Even if one accepts that the 42S was not a replacement for the 15C (and I am not arguing that point one way or the other--I do make the opposite case below) the argument that the 42S is obsolete because there are newer machines that were specifically designed to replace it that do more while the 15C is not obsolete because the machine specifically designed to replace it did not do a good job of that (your argument is that the 32S was supposed to replace the 15C) is somewhat disingenuous.

Basically the 42S is a far more capable machine than the 15C. Sure, it is a little bigger and uses menus but it is still a much more capable RPN machine than the 15C is. If the 15C has a place in today's world than the 42S does as well.

Anyhow, what exactly replaced the 42S? You claim that the 42S replacement(s) are the RPL line. Well even if one can make an argument for that (I always saw the RPL line as replacing the 41) it (the 42) still has advantages. it is a small, easily pocketable, scientific calculator using straight RPN (favored over RPL by many). Also, if you look at the dates of production according to the HP Museum web site you will note that the 42S was still being produced after the 28C/S and 48S/X were both discontinued. Sort of shoots down the argument that the 28 and 48 were replacements for the 42. Also note that the 48SX came out in 1990 while production of the 41 ended in 1990 (halfway through the production run of the 28S BTW). So timeline-wise the 48SX was the replacement for the 41.

Here are some of the dates:

HP-41C/V/X:  1979-1990
HP-15C:      1982-1989
HP-42S:      1988-1995
HP-28C:      1987-1988
HP-28S:      1988-1992
HP-48SX:     1990-1993

Given the above dates and the functionality offered by each of these models the 28C/S are really just a detour they don't replace anything. The 48SX replaces the 41C. And the 42S replaces the 15C. One could read this differently except that no one can realistically make the argument that the 42S was replace by either the 28 or the 48.

And the argument that the 15C was "low price"? Well the 42S was actually introduced at a lower price point. I don't know what the 15C was selling for at that point in time but my guess is that it was pretty close.

-Marwan

Edited: 8 Dec 2011, 1:32 p.m.

                                                                        
Re: HP-15C - useless today?
Message #32 Posted by bill platt on 8 Dec 2011, 2:57 p.m.,
in response to message #31 by M. Joury

And don't forget that HP even offered a 41 emulation or something for the 48SX--if I remember correctly it was an expansion card that had some sort of routine for running the 41 programs? I can't remember but someone here will :-)

                                                                              
Re: HP-15C - useless today?
Message #33 Posted by M. Joury on 8 Dec 2011, 3:58 p.m.,
in response to message #32 by bill platt

Yes, indeed. I have one :-). What more can one ask for proof?

It is an expansion card that emulates the HP-41. It can run programs and keyboard calculations, has full support for all HP-41 built-in functions (such as keyboard assignment/user mode) and can also be expanded by calling out to an RPL program (for example you can emulate the time and date functions of the 41 by using the time and date functions of the 48). You do this by writing an RPL routine that gets called in a special manner and assign it to an XROM number. I can't remember the details right now (it has been a while) but I created routines to support a number of the time module functions.

Cheers,

-Marwan

                                                                  
Re: HP-15C - useless today?
Message #34 Posted by Steve Fennell on 8 Dec 2011, 1:50 p.m.,
in response to message #29 by Dave

This was an interesting writeup. The first paragraph was enlightening on the 42s development.

Long Live the HP 42s

                                                                        
Re: HP-15C - useless today?
Message #35 Posted by M. Joury on 8 Dec 2011, 1:59 p.m.,
in response to message #34 by Steve Fennell

Thank you. Very interesting. Seems like the original intent was to replace the 41C and then later when HP decided that their high-end future calc was going to be the 48 they hobbled the device and realigned it as a 15C replacement.

Cheers,

-Marwan

                                                                  
Re: HP-15C - useless today?
Message #36 Posted by M. Joury on 8 Dec 2011, 2:13 p.m.,
in response to message #29 by Dave

Here is the issue that I have with your argument. The following two statements appear to be mutually exclusive:

Quote:
The 42S belongs in a museum because it has been far surpassed by later models. The 15C has not, and currently fills a niche no other calculator can fill.

Quote:
If you want to argue that the 42S is the successor to the 15C, then fine, it's a far better calculator in every way,

Who cares what was supposed to replace what. If it is a "far better calculator in every way" than how can you in the first quote say that it "belongs in a museum". If it is a batter machine it is a better machine and it does not much matter what came before or after it--it is still a better machine.

This is exactly the argument I was making with my first response. Why are we bothering to argue about what came first and what replaced what--if the 42S is better than the 15C it remains better than the 15C whether it was meant as a replacement for it or as a replacement for the 41.

You really can't have it both ways--claim that the 42S belongs in a museum while the 15C is still a usable machine and in the very next breath state that the 42S is a "far better calculator in every way".

-Marwan

Edited: 8 Dec 2011, 4:02 p.m.

                                                                        
Re: HP-15C - useless today?
Message #37 Posted by Dave on 8 Dec 2011, 6:18 p.m.,
in response to message #36 by M. Joury

Quote:
Here is the issue that I have with your argument. The following two statements appear to be mutually exclusive:

Who cares what was supposed to replace what. If it is a "far better calculator in every way" than how can you in the first quote say that it "belongs in a museum". If it is a batter machine it is a better machine and it does not much matter what came before or after it--it is still a better machine.

This is exactly the argument I was making with my first response. Why are we bothering to argue about what came first and what replaced what--if the 42S is better than the 15C it remains better than the 15C whether it was meant as a replacement for it or as a replacement for the 41.

You really can't have it both ways--claim that the 42S belongs in a museum while the 15C is still a usable machine and in the very next breath state that the 42S is a "far better calculator in every way".

-Marwan


You are confusing my exasperation with logic. I'm letting you have it both ways because I'm tired of arguing these silly semantics. The bottom line is the 42S is ugly and complicated. The 15C is elegant, simple and has no equal (literally).

I can't read HP executives' minds, but it was pretty clear to me as a consumer at the time that the 42S was intended to replace the 41, and that the only model anywhere close to the defunct 15C at the time was the 32S. The 42S was in a completely different class. I accept argument that the 15C was actually never replaced, which is why it's so great to have it back now.

If the 42S was such a perfect replacement, then why is there a much bigger demand for the 15C than the 42S? I think it comes down to styling and a perfect, though much more limited, function set for a pocket calculator.

                                                                              
Re: HP-15C - useless today?
Message #38 Posted by M. Joury on 8 Dec 2011, 6:56 p.m.,
in response to message #37 by Dave

Excuse me? It was not me that asked to have it both ways. All I said was that the 42S should not be relegated to a museum because if the 15C was such a great calculator than the 42S still has a place in the world.

The 42S is ugly? Personal opinion--don't try to tell me what I should like and that the 42S is (basically what you are saying) worthless because you find it ugly.

I don't care which calculator was meant to replace which. I have repeated that multiple times. Stop trying to fabricate an issue out of what came first and what came next. Simply put the 42S is more powerful than the 15C. That is a fact. Whether you prefer the looks of the 15C (which I like BTW) or not, whether you like the menu system of the 42S or not, etc. the 42 is simply a more powerful calculator.

Actually I would say that the 15C WAS replaced but that the 42S was never replaced.

Complicated? As far as menus go perhaps. As far as coding goes? The 42S is FAR easier to program simply because it has mnemonics and you don't have to rely on key codes. You can separate programs into their own logical entities so that numeric labels can be reused. It is much faster. And a whole slew of other improvements over the 15C (don't bother to tell me again that it wasn't meant as a replacement for the 15C--that does not justify the claim that it is a museum piece).

No one wants the 42S back? Try that one again! There are a LOT of people on this forum that would fall over themselves to buy a new 42S. Why do you think that the WP34S firmware was developed? Because people wanted a replacement for the 42S. If the 42S is a museum piece than so is the WP34S--so why are so many people on this forum interested in it? Maybe you are referring to sales on eBay? I have not tracked it recently but 12 years ago I sold a new-in-box HP-42S for $200+. I wonder what a NIB 42S would fetch now?

I really don't care which machine you like more. I personally think that the 15C is a great little calculator. What I had a problem with is that based on your personal opinion (you have given me no real data other than to argue about which calculator replaced which and to tell me that the 42S is ugly and complicated--I find it to be neither) you relegated the 42S (which I use far more often than my 15C) to an also ran, outdated, museum piece while holding up the 15C (you personal choice) as the only logical choice. That is not logic, that is personal preference which you have every right to. I have shared my opinions often enough on this forum to know that each and every one of us here have our favorites and when I state a preference I always add that "for me" or "for what I use it for" such and such works best. I like RPN, others like Algebraic, they are no more right or wrong than I am. These are all personal choices and all valid. I am very, VERY, careful not to say that such a calculator is better and that this other model is junk because that may not be true for someone else.

-Marwan

                                                                                    
Re: Bring Back 42s
Message #39 Posted by Kerem Kapkin (Silicon Valley, CA) on 8 Dec 2011, 9:52 p.m.,
in response to message #38 by M. Joury

+1 Bring back 42s (nice to have the 15C back, will be even better if get the 42s back, perhaps 42sx or 42s+)

Edited: 8 Dec 2011, 9:56 p.m.

                                                                              
Re: HP-15C - useless today?
Message #40 Posted by bill platt on 8 Dec 2011, 9:14 p.m.,
in response to message #37 by Dave

Your sarcasm was too obtuse for me (been 35 years since geometry) but now I get it!

Of course! If you were a 41 user back then and saw the 42, you would have been like, "this could have been so awesome!" But damit, what the hell?! No I/O?

And I have goo give you the idea that while the 32s is a very slight incremental improvement to the 11c, the 42s is a pretty big jump from the 15c.

                                                      
Re: HP-15C - useless today?
Message #41 Posted by Jake Schwartz on 7 Dec 2011, 5:04 p.m.,
in response to message #26 by Dave

Quote:
I guess Jake Schwartz makes up HP history too when he writes HERE that "Toward the end of 1988, HP introduced the non-expandable HP42S Pioneer model as a successor to the HP41 series."

I can't remember who that HP R&D guy was who attended a meeting of a local PPC chapter in the Corvallis area, but supposedly he showed to a few folks a prototype of a 42S with I/O. (Wlodek, you probably know who that is - was it Chris Bunsen, by any chance?) Apparently there were two simultaneous internal "camps" working on RPN and RPL and HP chose to go with RPL for the flagship position, relegating the 42S to having "O" without "I" and elevating the work toward the HP48SX, to be released on 3/6/90 (although without anything close to HP-IL).

Quote:
The 42S belongs in a museum because it has been far surpassed by later models.

If we were to restrict ourselves to RPN programmabbles, I'd say that the 42S was easily the pinnacle, with absolutely nothing more powerful. For those who prefer RPN programming to RPL, it is a shame that the 42S language never was ported to or further improved in a successor to this day.

Jake

                                                      
Re: HP-15C - useless today?
Message #42 Posted by bill platt on 7 Dec 2011, 6:25 p.m.,
in response to message #26 by Dave

Having bought an 11c the first year they came out, I can assure you, with absolutely no equivocation whatsoever, that the 32s was never marketed as a replacement for the 15c--it was marketed as an 11c replacement. The 33s and the 35s are 32sii clone/mods.

The 41/42 relationship is interesting, and perhaps Jake and Wlodek can fill us in with behind the scenes stories. But what I remember when I went to replace my lost 11c was that the 32sii was presented as its replacement...

                                                      
Re: HP-15C - useless today?
Message #43 Posted by Mike Morrow on 9 Dec 2011, 11:08 p.m.,
in response to message #26 by Dave

I see that you are unable to respond to my statement:

Quote:
It is nonsense to claim the keyboard/LCD/printer-only I/O 42S is "the replacement" for a device that can control multiple diverse devices on an HPIL loop, use input from a bar code reader, use a magnetic card reader, employ various other I/O and time modules, and utilize RAM and ROM memory of very many sorts. Exactly how does that "replacement" HP 42S "replace" any of such capabilities, or is that just some small and negligible and inconvenient detail?

There are no knowledgeable people who consider the HP 42S the replacement for the HP-41C series, for very obvious reasons...not today, not 23 years ago. Your argument that in the early design phase it was intended to be implemented as a replacement is gratuitous and specious in toto. The only thing that counts is what appeared on the market that customers could buy.

You obviously are not adequately familiar with the HP 42S and the HP-15C to be able to competently evaluate the relationship of the HP 42S to the HP-15C. Additionally, your statement that many more prefer the HP 15C rather than the HP 42S is demonstrably false, and, once again, completely gratuitous. A substantial part of your argument seems to be based simply on the Pioneer design being uglier than the Voyager design. I agree with that assessment, but within that ugly Pioneer design is a calculator that is orders of magnitude better than the HP-15C or HP 15C-LE. Beauty does not trump capability.

And...to return for the moment to the original thread, I agree that there is no real reason for the existence of the HP 15C-LE, except that it allows a lot of people to spend a fair amount of money on something they can pretend is an HP-15C. It is most definitely not the equivalent of the original HP-15C. It has many deficiencies in comparison to the original, and one and only one advantage...speed! But a very limited device like the HP-15C was seldom if ever used for calculations for which speed was of any real value. The inferior mechanical design and the significant errors in implementation of the HP-15C design (PSE bug, power management, self-tests, emulation rather than native uP code that wastes 90 percent of battery energy) ensure that the 15C (not LE) remains the machine to own, if its grossly superior HP 42S replacement is out of reach!

                                                            
Re: HP-15C - useless today?
Message #44 Posted by uhmgawa on 12 Dec 2011, 1:47 a.m.,
in response to message #43 by Mike Morrow

Quote:
And...to return for the moment to the original thread, I agree that there is no real reason for the existence of the HP 15C-LE, except that it allows a lot of people to spend a fair amount of money on something they can pretend is an HP-15C. It is most definitely not the equivalent of the original HP-15C. It has many deficiencies in comparison to the original, and one and only one advantage...speed! But a very limited device like the HP-15C was seldom if ever used for calculations for which speed was of any real value. The inferior mechanical design and the significant errors in implementation of the HP-15C design (PSE bug, power management, self-tests...

Emotionally, I (and I'm sure others) would like to argue with your assessment above. Unfortunately you speak the truth as thus far it primarily is a nostalgic collectable item.

I'm still mystified what HP's motivation was in this effort as I don't see how a return on the development investment would have produced a meaningful profit. So if it was a bow to their loyal following I really hope none of this discussion is received as an attempt to punish a good deed.

Quote:
emulation rather than native uP code that wastes 90 percent of battery energy)..

I don't think this is a valid claim. In any case we'd need to emulate the decimal ALU operations of the legacy 14 digit NUT processor via a functional reimplementation on the host processor. The fact we're feeding from a legacy voyager rom image vs. a rewrite of such has significant benefit. It is much easier to verify you've produced accurate NUT ALU emulation than verify a complete functional rewrite of the entire firmware. And a functional rewrite of 15c firmware isn't going to fit in 15KB of rom without substantial encoding of the ALU operations. We get that for free by running the native firmware with nearly each operation being encoded into 10 bits. So emulation is arguably the most efficient way to get the job done.

The problem with battery life lies simply with the chosen ARM core clock rate. A legacy NUT voyager draws approximately 1.1ma (15c) 730ua (11c/12c/16c) executing instructions at a target rate of 3947/s. An at91sam7l128 in the configuration used for an encore voyager is capable of a 36Mhz clock rate at a current consumption of ~20ma. Current draw parity with a legacy nut voyager occurs at about a 2Mhz clock rate. Assuming a 100x aggregate performance differential for the sam7 at 36Mhz, running at 2MHz would provide a ~6.7x improvement at the legacy current draw. Add to this the power source has changed from 3x SR44 to 2x CR2032, the latter of which provides over double the mAH capacity of the former. Running at 2Mhz with 2x CR2032 cells we're well in the recommended continuous current draw range for a CR2032 with a worst case continuous user program execution runtime ballpark of 400 hours. Or we could increase current consumption to the system equivalent of a legacy 15c while still remaining in the recommended load range for CR2032 cells, and achieve a throughput of ~14x.

Aside from core clock rate overkill, it is regrettable some firmware-external functionality wasn't provided in the emulator such as a facility to get code in/out of the device -- even if only as a means for wholesale backup of user programs. A bare-bones ubiquitous usb serial interface shouldn't have added more than US$3 manufacturing cost, if that.

Edited: 12 Dec 2011, 11:23 a.m.

                                                                  
Re: HP-15C - useless today?
Message #45 Posted by Mike Morrow on 13 Dec 2011, 1:37 p.m.,
in response to message #44 by uhmgawa

I wrote:

Quote:
The inferior mechanical design and the significant errors in implementation of the HP-15C design (PSE bug, power management, self-tests...

John wrote:

Quote:
Emotionally, I (and I'm sure others) would like to argue with your assessment above. Unfortunately you speak the truth as thus far it primarily is a nostalgic collectable item.

The current HP-12C models share the identical loss of mechanical quality of the HP 15C-LE, so that's just what the market will bear. My assessment does not mention an important ameliorating characteristic of the HP 15C-LE: It's far less expensive than the original HP-15C. I bought my first HP-15C new in 1985 for $100, which equates to $210 dollars in 2011. I suspect that if sufficient sales volume could be assured at that price, HP could produce a version that was equal in mechanical quality to the original, while using non-emulated firmware written from scratch for a fast SoC, just as was done recently by HP for the HP 30b and is being done independently for the WP 34S. But, for the $80 I paid for each of my HP 15C-LE units the quality-to-price ratio is still reasonably good, if one is an HP RPN nut.

Quote:
I'm still mystified what HP's motivation was in this effort as I don't see how a return on the development investment would have produced a meaningful profit. So if it was a bow to their loyal following I really hope none of this discussion is received as an attempt to punish a good deed.

I agree...I don't wish to be too critical of this little HP 15C-LE experiment. In a perfect world, the HP 17bii would have survived in the HP product catalog rather than the HP 12C clones. Perhaps then an HP 42S-LE would nave been issued, filling the very huge gap that has existed in RPN programmables since the HP 42S was discontinued 17 years ago. The HP 15C-LE fills no similar gap.

I wrote:

Quote:
...emulation rather than native uP code that wastes 90 percent of battery energy)

John wrote:

Quote:
I don't think this is a valid claim.

I think it's a valid claim. However, I agree that non-emulated firmware was never a reasonable expectation.

Emulations can waste an astonishing percentage (about 90 percent) of the battery's energy to accomplish a specific task, compared to a non-emulated machine. For example, here is data from a specific benchmark (2500-iteration Savage, see message 68 in this thread.):

On the 15C, it takes 5840 seconds. (original)
On the 15C-LE, it takes 48 seconds. (emulated SAM7 firmware)
On the 30b, it takes 6 seconds. (non-emulated SAM7 firmware)

The 15C-LE and the 30b use similar hardware and clock speeds. Yet the 30b completes this specific complex task eight times faster than the 15C-LE. It produces a result that has better precision and accuracy, with the error smaller by several orders of magnitude. My conclusion that it requires about nine times more energy for the 15C-LE system to complete the same task (ignoring the loss of precision) as the 30b is likely not far wrong. Emulation is thus responsible for a gross waste of battery energy without benefit to the calculation. Whatever energy is lost due to the pointless high speed of the 15C-LE is multiplied by the inefficiency of the emulation process. It causes the 15C-LE to run at least eight times longer than a hypothetical non-emulated version to perform the identical task.

I agree that there could be no other process other than emulation for the introduction of the 15C-LE. Since the 15C-LE is mostly a short-term odd-ball quirky product for "real fans", this doesn't matter much. Where emulation really hurts the HP product line is the HP 50g. At least it's better (except for alarms) than the original Saturn for speed, but only by about a factor of three. In fact, the same benchmark cited above takes 65 seconds on the HP 50g, 35 percent longer than the 15C-LE!

Edited: 13 Dec 2011, 2:51 p.m.

                                                                        
Re: HP-15C - useless today?
Message #46 Posted by uhmgawa on 14 Dec 2011, 5:18 p.m.,
in response to message #45 by Mike Morrow

Quote:
Emulations can waste an astonishing percentage (about 90 percent) of the battery's energy to accomplish a specific task, compared to a non-emulated machine. For example, here is data from a specific benchmark (2500-iteration Savage, see message 68 in this thread.):

On the 15C, it takes 5840 seconds. (original)
On the 15C-LE, it takes 48 seconds. (emulated SAM7 firmware)
On the 30b, it takes 6 seconds. (non-emulated SAM7 firmware)

The 15C-LE and the 30b use similar hardware and clock speeds. Yet the 30b completes this specific complex task eight times faster than the 15C-LE. It produces a result that has better precision and accuracy, with the error smaller by several orders of magnitude. My conclusion that it requires about nine times more energy for the 15C-LE system to complete the same task (ignoring the loss of precision) as the 30b is likely not far wrong. Emulation is thus responsible for a gross waste of battery energy without benefit to the calculation. Whatever energy is lost due to the pointless high speed of the 15C-LE is multiplied by the inefficiency of the emulation process. It causes the 15C-LE to run at least eight times longer than a hypothetical non-emulated version to perform the identical task.


Where a strict emulation approach can fall short are cases where the host processor is capable of a significantly more efficient native operation, from which the guest could benefit, but isn't easily inferred from the guest instruction stream. A good example here is the guest synthesizing a multiply operation via iterated shift/add operations, but the host cpu possesses a native multiply instruction. We really can't take advantage of the host multiply in general as we don't know when the guest is performing a multiply operation. We could decompile the guest code and patch the image, but again this isn't a general solution.

So in this sense, a functional simulator can free us from the programming model to which the emulator is bound. And in doing so if we can now leverage host resources previously unavailable, there is clearly a liability for an emulation approach -- but only necessarily in this case. Perhaps this is semantic hair-splitting but it isn't a limitation of emulation as an approach per se but a limitation of the programming model in use relative to the capability of the host cpu.

Quote:
Where emulation really hurts the HP product line is the HP 50g. At least it's better (except for alarms) than the original Saturn for speed, but only by about a factor of three. In fact, the same benchmark cited above takes 65 seconds on the HP 50g, 35 percent longer than the 15C-LE!

Actually I'm not a big fan of emulation either. The only justifiable case IMHO is when attempting to preserve the useful life of a precious bag of bits as in the 15c firmware. The moment we have need to modify those bits functionally (vs. administratively) the return falls off rapidly.

This discussion may soon be moot as I expect binary emulation in the context of pocket calculators will soon be significant only for technical historians.

      
Re: HP-15C - useless today?
Message #47 Posted by Dave Mabry on 5 Dec 2011, 9:47 a.m.,
in response to message #1 by Reth

Quote:
After playing a bit with the HP-15C LE (keyboard fixed) I'm under the impression, that apart of nostalgic reasons it is no worth getting it at all.

Does that mean you have a used one to sell? Seriously.

      
Re: HP-15C - useless today?
Message #48 Posted by Calum Tait on 6 Dec 2011, 4:50 a.m.,
in response to message #1 by Reth

I think of old calculators as like old cars. You can use a classic car as your "daily driver" as long as you can get parts for it, has room to transport you and your chattels and it more or less keeps up with the other traffic on the road. It just needs to be able to get you to where you want to travel and be pleasing to the eye or your personal sense of style. An old calculator must be able to do the calculations you need to do for your work or hobbies, must be reasonably reliable and be portable if that is required. I think the 15C, for many people, will do all the calculations they require reasonably reliably and does so with style and in a small form factor. Obviously there are some applications where it's limitations make it less useful but that can be said for all calculators, old or new. To argue that it doesn't have feature x or y or is slower than a more modern model is missing the point. You wouldn't use a Model T Ford on a motorway but if you never drive on a motorway, that isn't a problem. You can use a modern car for long distance touring or a computer for problems requiring high processing power. If it does what you need, then you don't need something else. I can't see how the 15C can be obsolete.

            
Re: HP-15C - useless today?
Message #49 Posted by Jeff Johnson on 6 Dec 2011, 9:59 a.m.,
in response to message #48 by Calum Tait

It's fun listening to this esoteric group bantering back and forth. I enjoy the energy and passion surrounding various models. While I appreciate the "purists" and their discussion of the finer points of various calculators (including "extreme" calculations, which are fun, and sometimes practical), there is indeed a group of us that use real calculators for "grunt" calculations on a daily basis. I do basic Algebra, Trig, Log type problems to calculate phase angle voltages, Line of Sight distances, microwave path losses, etc. I don't want to fire up Excel to do those calculations in the office, and it's even less practical when I'm out in the field. The scientific calculator is an EXTREMELY useful tool for my type of work. And, no, it's not just as easy to do those calculations on the soft HP calc on my Tablet PC. I'll grab a real, physical calculator every time, because it's faster to find and use. I can do my calculations equally well on my HP-45, HP-28c, HP-41c, HP-32sII, HP-25, HP-35s, or HP-50g. Until I retire, I will NEED a real calculator. Others may not, but that doesn't mean calculators are useless, including the venerable HP-15c. I will buy one when they become available at the retail price :o)

                  
Re: HP-15C - useless today?
Message #50 Posted by Martin Pinckney on 6 Dec 2011, 10:10 a.m.,
in response to message #49 by Jeff Johnson

Quote:
... there is indeed a group of us that use real calculators for "grunt" calculations on a daily basis ... I'll grab a real, physical calculator every time, because it's faster to find and use ... Until I retire, I will NEED a real calculator. Others may not, but that doesn't mean calculators are useless, including the venerable HP-15c.
Agreed. I find the 27s (it would be 42s if I were an RPN nut) to be more useful because of the alpha capability. But I can see how the 15c has a lot of appeal because of it's simple interface, everything's right there on the keyboard. If one prefers that type of interface, it would be hard to beat the 15c for an elegant implementation of the essential scientific calculator.
                        
Re: HP-15C - useless today?
Message #51 Posted by bill platt on 6 Dec 2011, 10:51 a.m.,
in response to message #50 by Martin Pinckney

I left one of my 27s machines on a KLM flight from Schipol to JFK in August :-(. Also a logitech M505 mouse.

I wonder how many great calculators are gathered up each year from the magazine pockets of airliners?

                              
Re: HP-15C - useless today?
Message #52 Posted by Martin Pinckney on 6 Dec 2011, 11:30 a.m.,
in response to message #51 by bill platt

Quote:
I wonder how many great calculators are gathered up each year from the magazine pockets of airliners?
Good question. At least they are not confiscated at security - yet.

Ever check out how many Leathermans are offered on eB** per month from airport confiscations? What part of "you cannot bring a sharp object on the plane" do they not understand?

                                    
Re: HP-15C - useless today?
Message #53 Posted by M. Joury on 6 Dec 2011, 2:38 p.m.,
in response to message #52 by Martin Pinckney

Actually you can. It is legal to take a pair of scissors of up to 4 inches onto an aircraft. Or so we have been told. We discovered this when my daughter tried to do exactly this so that she could work on some arts and crafts project she had. When we saw it we figured: A. They were going to give us a hard time and B. They would confiscate it. But no, we were informed that it was perfectly legal.

Do you know that you can take a pair of figure skates onto an aircraft? I am assuming that means that you can also board with speed skates. Have you ever seen how sharp those things are? And you could always sharpen them further.

On the other hand I was in a rush one day and forgot to take a mini Swiss army knife with a tiny little blade off my key-chain. That they of course confiscated.

And of course liquids are not allowed but milk and formula are exempt and can be taken on board.

Like a lot of things, airport security does not make a whole lot of sense.

-Marwan

Edited: 6 Dec 2011, 4:39 p.m. after one or more responses were posted

                                          
Re: HP-15C - useless today?
Message #54 Posted by bill platt on 6 Dec 2011, 3:49 p.m.,
in response to message #53 by M. Joury

It is purposely nonsensical. Its purpose is simply crowd control. Boot on your face. Do as we say.

Obviously if they were serious about the problem, All men would be banned from airplanes ;-)

                                                
Re: HP-15C - useless today?
Message #55 Posted by M. Joury on 6 Dec 2011, 4:48 p.m.,
in response to message #54 by bill platt

One of the "funniest" (as in illogical) experiences I have ever had...

My family flew up to Vermont from Richmond, VA a few years ago. My wife was going up there for an interview but we were scheduled to fly out separately and return together due to my work schedule. As it turned out we flew out together because a snow storm kept me from getting to work that day. At any rate that is not the point. The "funny" part occurred on the return.

We arrived at the airport together and we were going through security together. I am of pretty obvious Middle Eastern descent and my wife is an Italian blonde. At any rate we were going through security and my daughter and I passed through just fine but my wife got stopped and every item in her bags was taken out. When she asked why it was only her she was told that she was traveling alone (she was not on our itinerary since the tickets had been purchased separately) and that since I was traveling with our daughter I was obviously no threat. As it happens my daughter was at that point carrying my wife's carry on and she (my daughter) walked right through with no issues AFTER SECURITY SAW MY WIFE PLACE SOMETHING IN THE CARRY-ON! Gotta love how safe we are with the TSA taking care of us.

Cheers,

-Marwan

                                                      
Re: HP-15C - useless today?
Message #56 Posted by Bill (Smithville, NJ) on 6 Dec 2011, 6:12 p.m.,
in response to message #55 by M. Joury

Hi Marwan,

Well security is a funny business. Part of my job is designing security systems for the various buildings we design. I always meet with the client and ask a variation of the following question " What do you wish to acheive or what is the purpose/goal?" Often, they don't have any clear idea. How they answer this question determines whether they are looking for real security or show security. There may be several departments from the client and they will give conflicting requirements depending on their own viewpoint.

A usual conflict is protecting the building or equipment versus the people in the building and what are you protecting against.

So much of security is for show only. After 9/11, the casino where my wife worked, increased security in the garages - they were afraid someone would sneak a bomb into the garage and then blow up the casino garage (not really sure why they thought this). So my wife goes to work, they stop the cars in front of her and check their trunks and under the cars and then politely greet my wife and wave her thru since they know her. Security is only as good as the people implementing it and following thru on it.

The funny part is that a few years later, her casino was bought, and they blew it up to make way for a new casino (which they never built).

Bill

Edited: 6 Dec 2011, 7:45 p.m. after one or more responses were posted

                                                            
Re: HP-15C - useless today?
Message #57 Posted by bill platt on 6 Dec 2011, 6:33 p.m.,
in response to message #56 by Bill (Smithville, NJ)

Haha ironic.

Garages? Bombs? Probably from the 1st attempt at the World Trade Centers. On everyone's mind back then, including mine. I knew people on the top floor of that building who had to go to the roof to escape the smoke--which went up to the top floors and filled them.

I think anyone serious about security must read the chapter "Safecracker Meets Safecracker" in Feynman's autobiographical book.

                                                                  
Re: HP-15C - useless today?
Message #58 Posted by Bill (Smithville, NJ) on 6 Dec 2011, 7:47 p.m.,
in response to message #57 by bill platt

Hey Bill,

You realize by using the word "Bomb", our messages have probaly been scraped up and someone is now reading them to see if there is a threat. Crazy world.

Bill

                                                                        
Re: HP-15C - useless today?
Message #59 Posted by bill platt on 6 Dec 2011, 8:35 p.m.,
in response to message #58 by Bill (Smithville, NJ)

yep. J. Edgar looks like a 2-bit small timer compared to the dossiers on all of us today...

                                                                              
Re: HP-15C - useless today?
Message #60 Posted by Geoff Quickfall on 6 Dec 2011, 9:24 p.m.,
in response to message #59 by bill platt

I think the following story quite represents the idiocy of some aspects of screening. In case some don't realize, I go through security at airports around the world as part of my job (pilot).

Here is a first hand account of a brush with LHR (London Heathrow Security, flight and cabin crew bypass). I mention bypass for flight crew because you would think that these screeners would be looking for a different aspect of prohibited goods:

ME: "what in particular are you searching my flight bag for?"

SCREENER " Pardon me sir."

ME: " I would like to know, so that, if possible, I could leave it at home and preclude an invasive search of my FLIGHT BAG"

SCREENER "Oh, well, anything that will allow you to take control of the aircraft."

Now remember, I am a pilot of the flight, I am at crew bypass screening, I have uniform on, international (including HomeLand security) recognized electronic pass as well as pilot licence. So just WHAT in my flight bag were they looking for???

So now I just go to work, expect the least common denominator of common sense, then laugh about the insanity of it all.

Cheers, Geoff

p.s. the 15C rules, except for the 41CL and WP34S and 71B and 34 and 67 and 65 and 25 and ... personal choice which includes appearance, functionality (dependent on what you do or require it to do).

Cheers, again!

                                                                                    
Re: HP-15C - useless today?
Message #61 Posted by Ángel Martin on 7 Dec 2011, 2:01 a.m.,
in response to message #60 by Geoff Quickfall

LOL - yes, we don't want those dangerous pilots controlling the aircraft!!

Thanks for the early morning (my time) humor Geoff..

                                                                                    
Re: HP-15C - useless today?
Message #62 Posted by bill platt on 7 Dec 2011, 7:39 a.m.,
in response to message #60 by Geoff Quickfall

That is funny but stupid, too!

Here is another one for you:

Until the existence of the "smart phone" I used to use any of my calculators on the plane, with no restrictions. Now, I get told to "turn off your electronic devices:.

So far, they haven't told me to turn off my watch yet. Oh, I forgot. I don't wear a watch anymore.

                                                                                          
Re: HP-15C - useless today?
Message #63 Posted by Jim Yohe on 7 Dec 2011, 11:31 a.m.,
in response to message #62 by bill platt

So if you had on an HP-01 you could still use a "calculator" and they wouldn't know it or couldn't do anything about (I assume).

And I see there are still calculator watches made. Found this site for a more modern one (albeit they all seem to be from Casio):

http://www.calculatorwatchstore.com/

The CMD40B can even act as a remote control. LOL

Edited: 7 Dec 2011, 11:55 a.m.

                                                                                                
Re: HP-15C - useless today?
Message #64 Posted by Geoff Quickfall on 7 Dec 2011, 12:26 p.m.,
in response to message #63 by Jim Yohe

I wear the watch and carry the 41C in the shell through London on purpose:

Just my humour is all.

In fact, for a pilot, Tel Aviv is easier to get through then London or the US. However in the US the rules may be changing for flight crew, using a bypass instead of lining up with the passengers would shave an hour off our time and not degrade security in the least.

Geoff

                                                                                                      
Re: HP-15C - useless today?
Message #65 Posted by Jim Yohe on 7 Dec 2011, 1:04 p.m.,
in response to message #64 by Geoff Quickfall

I remember this from an earlier post by you. Beautiful Nixie watch! I think you said you put that tag around the battery. What battery model number is actually being used in it?

Never mind. I see it's a CR2 750mAh.

Edited: 7 Dec 2011, 2:57 p.m.

                                                                                                      
Re: HP-15C - useless today?
Message #66 Posted by Håkan Thörngren on 7 Dec 2011, 5:01 p.m.,
in response to message #64 by Geoff Quickfall

That 41C shell looks way cool, where did you find it?

                                                                                                
Re: HP-15C - useless today?
Message #67 Posted by Geoff Quickfall on 7 Dec 2011, 12:29 p.m.,
in response to message #63 by Jim Yohe

Take it a step further Jim, what happens with a pace maker, heart monitor, blood pressure monitor and etc?

Years ago before the madness started my Capt went through the magnitometer and beeped. Emptied his pockets and beeped again:

SCREENER: "your still beeping."

CAPTAIN: "I have an artificial hip."

SCREENER: "Show me."

cheers ;-)

                                                                                    
Re: HP-15C - useless today?
Message #68 Posted by Jeff Johnson on 7 Dec 2011, 11:09 a.m.,
in response to message #60 by Geoff Quickfall

Pretty funny, Geoff. I work as Tech Support for the FAA's Indianapolis ARTCC. Although I haven't had anything to do with Security since our security people split off and became TSA, I have continued to be amused by the screening of pilot's belongings. Same goes for arming pilots. Can that be *more* dangerous, when you're already trusting your LIFE to that pilot? If a pilot wants to kill everybody on board, he doesn't need ANY carry-ons. Sanity and logic apparently have little say-so in security. Similar things happen at our FAA facilities. They go out of their way to screen, check, limit, train, restrict us as engineers, technicians, controllers, etc, yet I could walk into a cipher-locked room in our basement and in 10 seconds, ground traffic from LA to Boston with nothing but a set of bolt cutters. Aside from my obvious termination, there would also be delays for many, many hours and millions of dollars lost by the airlines. Where does screening stop and trust begin? Tough question.

                                                                                          
Re: HP-15C - useless today?
Message #69 Posted by bill platt on 7 Dec 2011, 6:20 p.m.,
in response to message #68 by Jeff Johnson

It's actually a really easy question. If you can be trusted as an employee, you can be trusted. Period. :-)

                                                      
Re: HP-15C - useless today?
Message #70 Posted by bill platt on 6 Dec 2011, 6:30 p.m.,
in response to message #55 by M. Joury

LOL Italian blond. They are knock-out killers, for sure!

                                    
Re: HP-15C - useless today?
Message #71 Posted by Les Bell on 7 Dec 2011, 2:07 a.m.,
in response to message #52 by Martin Pinckney

Quote:
Ever check out how many Leathermans are offered on eB** per month from airport confiscations? What part of "you cannot bring a sharp object on the plane" do they not understand?

My Leatherman is engraved "Aircraft Owners and Pilots Association" and is intended for use on aircraft. I leave it behind when flying commercially, although I did once use it to fix up some loose cabin trim on a Qantas flight.

--- Les
[http://www.lesbell.com.au]

                              
Re: HP-15C - useless today?
Message #72 Posted by Michael de Estrada on 6 Dec 2011, 11:37 a.m.,
in response to message #51 by bill platt

That's why the Victor V12 is made.

                        
Re: HP-15C - useless today?
Message #73 Posted by Thomas Radtke on 6 Dec 2011, 12:42 p.m.,
in response to message #50 by Martin Pinckney

Quote:
Agreed. I find the 27s (it would be 42s if I were an RPN nut) to be more useful because of the alpha capability.
Please correct me if I'm wrong: The 42S is missing the RPL solver, which makes the 27S so incredibly useful. If I'm not completely wrong, there's no RPN scientific offering it. The 32SII and successors come close, but are quite limited due to being fixed to single letter variables.
                              
Re: HP-15C - useless today?
Message #74 Posted by Martin Pinckney on 6 Dec 2011, 12:51 p.m.,
in response to message #73 by Thomas Radtke

Quote:
Please correct me if I'm wrong: The 42S is missing the RPL solver, which makes the 27S so incredibly useful. If I'm not completely wrong, there's no RPN scientific offering it. The 32SII and successors come close, but are quite limited due to being fixed to single letter variables.
The 42s has a Solver, but it is not as easy to use, because you first have to write a program to solve the equation, instead of just writing the equation. However, once you've written the program, the 42s Solver is just as easy to use.

There was one RPN model with the 27s type of Solver, the 17bii, but you are correct, it's not scientific.

                                    
Re: HP-15C - useless today?
Message #75 Posted by Thomas Radtke on 6 Dec 2011, 1:24 p.m.,
in response to message #74 by Martin Pinckney

Quote:
The 42s has a Solver, but it is not as easy to use, because you first have to write a program to solve the equation, instead of just writing the equation.
That's fine, but the RPL solver, first appeared in the 18C, allows to solve for any variable. This isn't easily possible with the 42S, is it?
                                          
Re: HP-15C - useless today?
Message #76 Posted by Martin Pinckney on 6 Dec 2011, 1:45 p.m.,
in response to message #75 by Thomas Radtke

I'm not sure what you mean by "RPL Solver", but I assume it is the type that is in the 27s/17b. AFAIK the 42s Solver does allow solving for any variable once you have entered a correct program representing the equation.

For some problems you have to enter an initial guess, but this is also true on the 27s as well.

                                          
Re: HP-15C - useless today?
Message #77 Posted by M. Joury on 6 Dec 2011, 2:45 p.m.,
in response to message #75 by Thomas Radtke

Absolutely can. From a user's perspective looks just like the 17bii. Coding the problem is of course different.

Here is a simple example:

Temperature conversion:

01 LBL "Temp"
02 MVAR "oF"  
03 MVAR "oC"
04 RCL "oC"
05 1.8
06 *
07 32
08 +
09 RCL "oF"
10 -
11 END

This would be the equivalent of:

oCx1.8+32=oF

on the 17bii.

Cheers,

-Marwan

Edited: 6 Dec 2011, 6:21 p.m. after one or more responses were posted

                                                
Re: HP-15C - useless today?
Message #78 Posted by Thomas Radtke on 6 Dec 2011, 3:31 p.m.,
in response to message #77 by M. Joury

Martin, Marwan, thanks for the explanation. I've never owned a 42S and never heard of this way to code a solver program. Missed this in nearly 20 years of using HP calcs. Amazing.

Edited: 6 Dec 2011, 3:32 p.m.

                                                      
Solve for any variable
Message #79 Posted by Masaki Adachi on 7 Dec 2011, 10:10 a.m.,
in response to message #78 by Thomas Radtke

Quote:
RPL solver, first appeared in the 18C, allows to solve for any variable. This isn't easily possible with the 42S, is it?

Quote:
Absolutely can.

I too, missed this. but then my first HP calculator was 28C. All other HP product calculators I obtained since then had a Equation solver (HP200LX, 48G,33S,35S) where i could just enter a equation. I never thought hp42S solve (in my case free42) could do this.

That "discovery" begs a question. Is it also possible to do this with WP34S? I could not figure this out from reading the manual.

                                                            
Re: Solve for any variable
Message #80 Posted by M. Joury on 7 Dec 2011, 11:10 a.m.,
in response to message #79 by Masaki Adachi

I don't believe so.

One issue would be that the HP30b/WP34S display does not support a menu system like that of the 42S/17bii/27S etc. So another approach would have to be devised to support such functionality.

Cheers,

-Marwan

                                                                  
Re: Solve for any variable
Message #81 Posted by Masaki Adachi on 7 Dec 2011, 11:23 a.m.,
in response to message #80 by M. Joury

Quote:
One issue would be that the HP30b/WP34S display does not support a menu system like that of the 42S/17bii/27S etc. So another approach would have to be devised to support such functionality.


On HP33S/35S for instance,procedure is as follows.

Key 'EQN'

Scroll and select the equation that you want to solve.

Key 'Solve" then enter 'A'

then the calculator asks for 'B?' and then 'C?' (for equation A+B=C)

so interface-wise, it appears do-able with 20b/30b LCD display.

Edited: 7 Dec 2011, 11:26 a.m.

                                                                        
Re: Solve for any variable
Message #82 Posted by M. Joury on 7 Dec 2011, 12:35 p.m.,
in response to message #81 by Masaki Adachi

Yes. But much less elegant :-).

Cheers,

-Marwan

                                                                  
Re: Solve for any variable
Message #83 Posted by Thomas Radtke on 7 Dec 2011, 11:31 a.m.,
in response to message #80 by M. Joury

Quote:
So another approach would have to be devised to support such functionality.
A solver could ask for a register to solve for instead of using the x-register. The user would then be required to fill in given values into the remaining registers before calling solve. Maybe a useful extension..?

With some luck, it already works this way (don't know the wp34s either :-D).

                                                                        
Re: Solve for any variable
Message #84 Posted by Marcus von Cube, Germany on 7 Dec 2011, 12:34 p.m.,
in response to message #83 by Thomas Radtke

You enter the label with SLV and the solver always searches for a zero of the program depending on X. I don't see an easy way to change its behavior.

                                                                              
Re: Solve for any variable
Message #85 Posted by Thomas Radtke on 7 Dec 2011, 1:00 p.m.,
in response to message #84 by Marcus von Cube, Germany

Quote:
You enter the label with SLV and the solver always searches for a zero of the program depending on X. I don't see an easy way to change its behavior.
(1) enter initial guess into eg. register r0 (or whatever you have)
(2) call the solver
(3) enter program to solve
(4) enter register descriptor for r0

The solver would then feed the current guess into r0 instead of x.

Edited: 7 Dec 2011, 1:01 p.m.

                                                                                    
Re: Solve for any variable
Message #86 Posted by Marcus von Cube, Germany on 7 Dec 2011, 2:10 p.m.,
in response to message #85 by Thomas Radtke

Quote:
(1) enter initial guess into eg. register r0 (or whatever you have)
(2) call the solver
(3) enter program to solve
(4) enter register descriptor for r0

The solver would then feed the current guess into r0 instead of x.


The solver is not interactive so it has no way of querying any additional parameters beyond what's already part of the command (the label of the routine to solve).

Edited: 7 Dec 2011, 2:13 p.m.

                                                                                          
Re: Solve for any variable
Message #87 Posted by Marcus von Cube, Germany on 7 Dec 2011, 3:11 p.m.,
in response to message #86 by Marcus von Cube, Germany

Thinking a bit further, it's not too complicated to create a routine that can be solved for any of its variables, just by using a pointer register:

LBL 00
STO[->]00
RCL 01
RCL 02
RCL 02
[times]
-
RTN

You can STO 1 or 2 in r00 and the routine will then solve for this register. STO the parameter in the other register before executing SLV 00.

                                                                                                
Re: Solve for any variable
Message #88 Posted by Thomas Radtke on 8 Dec 2011, 2:19 a.m.,
in response to message #87 by Marcus von Cube, Germany

That's actually how I do it on the 15C, but thought it would be easier to remember a slightly different invocation of the solver. Maybe it's not worth it.

                                                
Re: HP-15C - useless today?
Message #89 Posted by Don Shepherd on 6 Dec 2011, 3:34 p.m.,
in response to message #77 by M. Joury

Quote:
*Cx1.8+32=*F

On the 17b, 17bii, or 17bii+, instead of * to indicate degrees, I would use the actual degree symbol o since it is available on the set of symbols and can be part of the variable name.

                                                      
Re: HP-15C - useless today?
Message #90 Posted by M. Joury on 6 Dec 2011, 4:35 p.m.,
in response to message #89 by Don Shepherd

Yes. That is what I meant by '*' represents the degree symbol. I actually use the degree symbol on both the 17bii and the 42S. I just didn't bother to find the PC equivalent.

Cheers,

-Marwan

                                                            
Re: HP-15C - useless today?
Message #91 Posted by Don Shepherd on 6 Dec 2011, 4:52 p.m.,
in response to message #90 by M. Joury

In this forum, [super]o[/super] works nicely.

                                                                  
Re: HP-15C - useless today?
Message #92 Posted by M. Joury on 6 Dec 2011, 5:11 p.m.,
in response to message #91 by Don Shepherd

Thanks. I'll try to remember that :-).

                                                                        
Re: HP-15C - useless today?
Message #93 Posted by bill platt on 6 Dec 2011, 6:36 p.m.,
in response to message #92 by M. Joury

I love everything about this forum.

                                                
Re: HP-15C - useless today?
Message #94 Posted by Martin Pinckney on 6 Dec 2011, 10:24 p.m.,
in response to message #77 by M. Joury

Quote:
Here is a simple example:

Temperature conversion:

01 LBL "Temp"
02 MVAR "oF"  
03 MVAR "oC"
04 RCL "oC"
05 1.8
06 *
07 32
08 +
09 RCL "oF"
10 -
11 END

This would be the equivalent of:

oCx1.8+32=oF

on the 17bii.


This is an excellent example of the beauty of working with the 17b/27s Solver versus RPN solvers.
                                                      
Re: HP-15C - useless today?
Message #95 Posted by M. Joury on 7 Dec 2011, 11:17 a.m.,
in response to message #94 by Martin Pinckney

Quote:
This is an excellent example of the beauty of working with the 17b/27s Solver versus RPN solvers.

Or the power and versatility of the HP42S solver :-). Don't get me wrong, the 17bii solver is great. But, for me at least, the 42S solver is easier to work with for complex problems.

Cheers,

-Marwan

                                                            
Re: HP-15C - useless today?
Message #96 Posted by Martin Pinckney on 7 Dec 2011, 11:34 a.m.,
in response to message #95 by M. Joury

We really should be comparing the 27s Solver, because it is scientific like the 42s, rather than business.

But I'm curious, how is the 42s solver easier to work with, when you first have to write a program in RPN to solve the equation, debug it, instead of just keying in the equation?

                                                                  
Re: HP-15C - useless today?
Message #97 Posted by Jim Yohe on 7 Dec 2011, 11:40 a.m.,
in response to message #96 by Martin Pinckney

Exactly!

... though I'll probably be sorry for agreeing so heartily. ;-)

                                                                  
Re: HP-15C - useless today?
Message #98 Posted by M. Joury on 7 Dec 2011, 12:45 p.m.,
in response to message #96 by Martin Pinckney

For complex problems. The problem I offered above would definitely not fall into that category and is much easier to solve with the 17bii. Remember that with the 42S you have the power of a full programming paradigm to work with. While I have seen a lot of very interesting problems solved with the 17bii there are problems that don't fall easily into the equation paradigm.

Also, I find RPN programming extremely easy so, while I agree that for simple problems the 17bii is easier to work with, for more complex problems I find the 42S easier to work with -- note that I said "for me at least" in my original post.

Cheers,

-Marwan

                                                                        
Re: HP-15C - useless today?
Message #99 Posted by Don Shepherd on 7 Dec 2011, 1:37 p.m.,
in response to message #98 by M. Joury

This is an interesting discussion of the types of solvers in HP calculators. I can't help but compare the solvers in the 32s and 32sii. The 32s solver requires you to write an RPN program, I guess much like the 42 (and 30b). The 32sii offers an algebraic solver, similar to the solver in the 17b and 27s but without the power of and IF and menus.

Unless you want to learn some basic tenets of RPN programming, you won't be able to use the 32s solver, but anyone who can type an equation can use the 32sii algebraic solver. I would imagine that is why HP changed the solver approach between the 32s and the 32sii. Although I know RPN, I much prefer the 32sii approach.

I personally am attracted to the the power of the 17b/19b/27s solver, since it contains several features (like loops and decisions) that standard solvers do not.

                                                                        
Re: HP-15C - useless today?
Message #100 Posted by Martin Pinckney on 7 Dec 2011, 2:01 p.m.,
in response to message #98 by M. Joury

Quote:
For complex problems. The problem I offered above would definitely not fall into that category and is much easier to solve with the 17bii. Remember that with the 42S you have the power of a full programming paradigm to work with. While I have seen a lot of very interesting problems solved with the 17bii there are problems that don't fall easily into the equation paradigm.
We are talking about solvers here, which AFAIK implies using equations. Granted, using straight RPN programming affords more raw problem-solving power, especially with a calculator as robust as the 42s. But you can't just write any RPN program and then solve for any variable with the Solver. You have to have a valid equation to solve first, then write a program to represent it.

So my question still begs an answer, how is the 42s solver easier to work with than the 27s Solver?

Unless I am missing something.

                                                                              
Re: HP-15C - useless today?
Message #101 Posted by M. Joury on 7 Dec 2011, 4:50 p.m.,
in response to message #100 by Martin Pinckney

For anything that requires branching, particularly nested branching, I prefer the 42S approach. Not that the same thing can not be achieved with the 17bii, it is just my preference.

You could of course argue that at this point (nested branching) we are no longer talking about a solver equation per your definition and I would probably have to give you that.

BTW, for most of my regular equations I do use the 17bii solver rather than that of the 42S. I rarely use the 27S simply because it is not RPN.

Cheers,

-Marwan

                                                                                    
Re: HP-15C - useless today?
Message #102 Posted by Martin Pinckney on 7 Dec 2011, 5:08 p.m.,
in response to message #101 by M. Joury

It's not my definition, it's HP's. This portion of the thread was about what HP calls "Solver", not "solving problems by the method most preferred by the user". I understand you prefer RPN programming; I was just trying to understand your rationale for stating that using the 42s Solver was easier than the 17b/27s Solver.

                                                                                          
Re: HP-15C - useless today?
Message #103 Posted by M. Joury on 7 Dec 2011, 6:22 p.m.,
in response to message #102 by Martin Pinckney

Maybe I was not clear. I was talking about branching within a solver routine. You asked for an example of something that both the 42S and the 27S/17bii could do within their respective solvers that I found easier to do on the 42S. For me branching is an example of such.

My statement that this maybe outside your original definition was referring to the fact that such a solution is not a straight equation. I was not switching the topic to discuss overall programming capability. Also that is what I was referring to when I originally said that I sometimes find complex solutions easier to code on the 42S--I was not limiting my definition to straight equations.

As stated earlier, for simple (in this case read no branching) solutions the 17bii and the 27s solvers are much more intuitive and easier to use. Even for an RPN fanatic like me.

Sorry for any lack of clarity.

Cheers,

-Marwan

                                                                                                
Re: HP-15C - useless today?
Message #104 Posted by Martin Pinckney on 8 Dec 2011, 9:02 a.m.,
in response to message #103 by M. Joury

Yes, that does clarify it. Now that intrigues me to understand how I might use the 42s Solver for branching equations. I understand how to do those on the 27s, but never tried it on 42s.

Thanks!

            
Re: HP-15C - useless today?
Message #105 Posted by Martin Pinckney on 6 Dec 2011, 10:04 a.m.,
in response to message #48 by Calum Tait

Calum,

For my money this is the best argument presented.

Except your choice of a Model T was unfortunate, IMO. The Model T is more analogous to the old Monroe (Olympia) hand-crank four-banger mechanical calculator of the 1950s/60s.

                  
Re: HP-15C - useless today?
Message #106 Posted by Calum Tait on 6 Dec 2011, 8:20 p.m.,
in response to message #105 by Martin Pinckney

You are probably right with the analogy. Please feel free to substitute your classic motor of choice for the Model T!

      
Re: HP-15C - useless today?
Message #107 Posted by Dave Mabry on 11 Dec 2011, 7:45 p.m.,
in response to message #1 by Reth

Quote:
After playing a bit with the HP-15C LE (keyboard fixed) I'm under the impression, that apart of nostalgic reasons it is no worth getting it at all. Its low internal accuracy makes it hopeless and also makes HP-35S look acceptable. Both can't compare with the BRILLIANT Free 42S by Thomas Okken and more so with Byron Foster's implementation for iPhone. I wander who would use it today for real work?


I'm seriously waiting for an answer to my question. I'm willing to buy that useless HP-15C LE from you. If it is, indeed, useless you should be willing to sell it. Or am I wrong about you even having one. Did you buy one? Wanna sell it???


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