Casio fx-50F/fx-50FH programming

[johanw]

(08-20-2020 08:10 AM)David22 Wrote:  but MUCH WORSE: DM41, like all SwissMicros not only has dot-matrix display, but also programmable firmware, so you can change it and create a cheat tool, even without changing calculator hardware.

I'd say that someone who manages to adapt the firmware for a a DM41/1x with something that allows to store a few lines of text already knows those text lines. They run on an emulator with the original firmware, and it was already extremely difficult for SM to adapt the DM15 firmware to allow for more program steps than the original HP15C.

Examination bodies should better develop better exams, I was allowed to use my own notes and sometimes even textbooks at exams, so the exams look more like a real situation you might encounter: if I don't know something at work I look it up in a book or on the internet.

[Albert Chan]

(08-21-2020 01:04 PM)johanw Wrote:  Examination bodies should better develop better exams, I was allowed to use my own notes and sometimes even textbooks at exams, so the exams look more like a real situation you might encounter: if I don't know something at work I look it up in a book or on the internet.

I am on the opposite camp. Calculators should be banned in exams.

Why do students that can afford a programmable calculator have the advantage ?
Or, worse, a cheating calculator ...

Answer is considered correct if you write the steps, leaving the arithmetics un-calculated.
You get bonus points if you can estimate the result.

On the other hand, a correct numerical result without showing why get no points.

[johanw]

(08-21-2020 02:00 PM)Albert Chan Wrote:  Why do students that can afford a programmable calculator have the advantage ?

Afford? When I checked what I spend on books for my study, the calculator I used then (a Casio FX-8000G which I paid 299 Guilders for in 1988 - about 135 Euro) - was not the most expensive part of my study. On some exams I could not use it, there I used a non-programmable scientific calculator. College tuition was around 1350 Euro / year then.

Quote:Answer is considered correct if you write the steps, leaving the arithmetics un-calculated.

That was always the case in university and high school. Just writing down a number without explaining how you got it was 0 points (we didn't have multiple choice exams). And some examinations were a 1 on 1 questioning by a teacher where you had to solve, (or start solving when it would take too long to finish it completely), problems, so no cheating possible there.

Quote:You get bonus points if you can estimate the result.

That is a usefull skill on its own.

[David22]

(08-21-2020 01:04 PM)johanw Wrote:  I'd say that someone who manages to adapt the firmware for a a DM41/1x with something that allows to store a few lines of text already knows those text lines. They run on an emulator with the original firmware, and it was already extremely difficult for SM to adapt the DM15 firmware to allow for more program steps than the original HP15C.

You are right, DM41 has small memory to store a lot of text information, at least if you want to conserve HP15C emulation for example. But, I don't know if in lower models emulation (for example HP11C) there is much more free memory in firmware, so it can be used to cheat. On other way this machines have full dot-matrix display, and they can be hacked (even by hard) to store and show a lot of information, even wireless comms.

About SwissMicros I was thinking on DM42: this model has a lot of flash memory: 6MB, most of it free to user (original HP42s have 8KB RAM to store data). I like SwissMicros machines, but I hate its web page (for example there is no good info about other models than DM42). I'd like they make a DM50g with that high-resolution and high-contrast Sharp Memory LCD like DM42 (there is a bigger Memory LCD with 320x240 pixels) but I think it is difficult because it is a much more complex machine.

[David22]

(08-21-2020 02:00 PM)Albert Chan Wrote:  I am on the opposite camp. Calculators should be banned in exams.

Why do students that can afford a programmable calculator have the advantage ?
Or, worse, a cheating calculator ...

Answer is considered correct if you write the steps, leaving the arithmetics un-calculated.
You get bonus points if you can estimate the result.

Today programmable calcs are cheap, at least in not very poor countries (you must relate price to income), and there is a big 2nd hand market, so I think owning one is not a problem in most countries.

On other side I think part of the problem is with cheating, from including a lot of information on internal memory on standard machine to modified machines with even more memory or even wireless comms capabilities. This is a reason to ban a lot of calcs (all having dot-matrix displays).

Also I see a other problem with calculators which can do a lot work, work some students doesn't how to do.

For all those reasons I think only 7-segments calc would be allowed in exams: they free you from tedious arithmetic calcs, but you can't cheat with them as there is no text (even if they are programmable), and they give instantaneous results as you press keys (i.e. you get intermediate results as you do it).

I think those instant result calcs (they give result as you press keys; for example you press SIN key and they answer with sine value), are better for learning because you see results on operations. For example, when you are young you press 1/x and you see inverse, you press it again and you get previous number: you see in practice characteristics of inverse operation. In a modern calculator you introduce a formula and you don't see those effects, you learn nothing with them, you can't play with numbers with them.

Even it could be acceptable a 7-sgemsnts display with a small text area, with maximum 4 chars to show program or extra information (for example modes, matrices editing, etc) or error information. Some old Casio had this 4-chars area (for example fx-180P Plus, fx-3900Pv). With 4 chars text it is really impossible to cheat in a good way. Even with 7-segments you can do matrix operation (HP15C is an example), and you can include 2 lines of 7-segments with extra symbols to easy operation on matrix, programming, etc, without cheating possibilities.

Of course today calc industry is on other way, and cheap 7-segments calcs is little money to gain for them (except for venerable and expensive HP12C, longest live calc in history ).

(08-21-2020 02:00 PM)Albert Chan Wrote:  On the other hand, a correct numerical result without showing why get no points.

Of course, in a normal (no select-answer) exam it is simply zero points.

But I made select-correct-answer exams in some high grade subjects, so there you only choose a solution from for example 4 provided correct/fault solutions. And an exam like those can be even harder than a normal exam if they want to do so (even if they point up no answered questions; of course incorrectly answered questions get negative points, so you must only answer when you are confident about solution).

[Massimo Gnerucci]

(08-25-2020 12:14 PM)David22 Wrote:  For all those reasons I think only 7-segments calc would be allowed in exams: they free you from tedious arithmetic calcs, but you can't cheat with them as there is no text (even if they are programmable),

If we are into modifying ROMs you can always devise something up...

[David22]

(08-25-2020 12:28 PM)Massimo Gnerucci Wrote:  

(08-25-2020 12:14 PM)David22 Wrote:  For all those reasons I think only 7-segments calc would be allowed in exams: they free you from tedious arithmetic calcs, but you can't cheat with them as there is no text (even if they are programmable),

If we are into modifying ROMs you can always devise something up...

Thank you very much for graphical info about 7-segments capabilities I have never saw that complete set

I like it but the fact is that it is really hard to read, really you need to learn a new letter/symbol set, and one not very clear one (for example * is the usual grade/° symbol). I don't see lazy cheater learning that strange and low-productivity symbol set to cheat. To use later a name and a formula in that symbol set is really hard: it requires a lot of train, something a cheater is not going to do. And it adds up to the fact that 7-segments displays have only 10-12 digits display, so you can only show 10-12 chars in that strange and difficult to read symbol set.

If alphabetic capabilities calculator began with 14-segments display (HP-41C), not with 7-segments, I think it was for a reason: you need to learn a new and strange symbol set.

[Massimo Gnerucci]

(08-25-2020 01:13 PM)David22 Wrote:  

(08-25-2020 12:28 PM)Massimo Gnerucci Wrote:  If we are into modifying ROMs you can always devise something up...

Thank you very much for graphical info about 7-segments capabilities I have never saw that complete set

I like it but the fact is that it is really hard to read, really you need to learn a new letter/symbol set, and one not very clear one (for example * is the usual grade/° symbol). I don't see lazy cheater learning that strange and low-productivity symbol set to cheat. To use later a name and a formula in that symbol set is really hard: it requires a lot of train, something a cheater is not going to do. And it adds up to the fact that 7-segments displays have only 10-12 digits display, so you can only show 10-12 chars in that strange and difficult to read symbol set.

If alphabetic capabilities calculator began with 14-segments display (HP-41C), not with 7-segments, I think it was for a reason: you need to learn a new and strange symbol set.

Our brain is quite adaptable:

[Didier Lachieze]

(08-25-2020 03:21 PM)Massimo Gnerucci Wrote:  Our brain is quite adaptable:]

Yes, it is quite good at Pattern Matching. It was, I suppose, a key factor to survive a long time ago, when you had to quickly identify what could be dangerous or recognize what you can eat safely.

I'm proud of my brain, even if the reading was not fully automatic on the first pass

[David22]

(08-25-2020 03:21 PM)Massimo Gnerucci Wrote:  Our brain is quite adaptable:

I don't think that text can be translated to 7-segment strange alphanumeric letters. That text uses the fact that usually we don't read individual letters, but entire words, so you can adapt, and on other side selected numbers for letters have similar shape (3 for E, 5 for S...) but I think with 7-segments it would be much much difficult. And much worse: you need not only text but totally exact formulas, where you can NOT play with seeing complete words you knew before.

And with 7-segmnts it needs train/time, something a lazy cheater doesn't have.

But it would be interesting to see a text in 7-segments (only letters), to know how good we can adapt. With text+symbols/formulas I don't see it be easy: lot of 7-segments symbols are too much difficult to distinguish (I am looking for a 7-segments font for LibreOffice Writer). Of course, with time/train you can do it and more, but a cheater doesn't have time for that.

[David22]

(08-25-2020 03:21 PM)Massimo Gnerucci Wrote:  Our brain is quite adaptable:

Some adaptations are harder:



If it would be text plus complex formulas it would be much much harder to read on 7-segments.

[David22]

(08-25-2020 03:21 PM)Massimo Gnerucci Wrote:  Our brain is quite adaptable:

I think most brains are not so adaptable to read text plus complex formulas with 10 chars using 7-segment display.

We can see a simple quadratic formula from elementary algebra displayed in normal plain text with normal letters+symbols and then with 7-segments display:



And it is a simple formula: there are much longer and complex formulas/content.

PD: Jim Parsons (he plays Sheldon Cooper) can't remember this elementary formula:

[Dave Britten]

(08-25-2020 05:38 PM)David22 Wrote:  

(08-25-2020 03:21 PM)Massimo Gnerucci Wrote:  Our brain is quite adaptable:

I think most brains are not so adaptable to read text plus complex formulas with 10 chars using 7-segment display.

We can see a simple quadratic formula from elementary algebra displayed in normal plain text with normal letters+symbols and then with 7-segments display:



And it is a simple formula: there are much longer and complex formulas/content.

Doesn't look any harder than Morse code or Braille.

(Easier, in fact.)

[Massimo Gnerucci]

(08-25-2020 04:59 PM)David22 Wrote:  

(08-25-2020 03:21 PM)Massimo Gnerucci Wrote:  Our brain is quite adaptable:

Some adaptations are harder:



If it would be text plus complex formulas it would be much much harder to read on 7-segments.

Could read it easily, actually. :)

But you have your truth so I won't argue further.

And, BTW, why are you so obsessed with cheaters? it is not my first thought when I grab a calculator.

[David22]

(08-25-2020 08:37 PM)Massimo Gnerucci Wrote:  Could read it easily, actually.

You can read text easily, but reading text and complex formulas is not so easy: some people would never be comfortably enough, most people would need training, something a lazy cheater won't do.

(08-25-2020 08:37 PM)Massimo Gnerucci Wrote:  And, BTW, why are you so obsessed with cheaters? it is not my first thought when I grab a calculator.

I'm not obsessed with cheaters but with calculator ban, and cheaters are helping to go forward with that ban.

I don't choose my calcs with cheaters in mind. In fact my favourite calculators are HP48SX/GX (with my GX plus cards I can have up to 1,25 MB RAM), also I own HP50g and TI-89/92Plus, and you have CAS with them and you can store a lot of information on them.

When I think in a ban scenario I understand the problem, and I see 7-sgment displays as a good solution: cheating is impossible or at least very limited. At the same time I see them better for a lot of students: those calcs, even if programmable (I own a few 7-segment display programmable calcs in my collection, including HP67 and HP15C) produce instant results, you press a key and you do something with those numbers, and you must to know what you are doing, and at the same time you can learn from it. A simple example is to press 1/x and watch how when you press repeatedly you get inverse and original number repeatedly. With modern calculators you type a complete expression, sometimes written like in a textbook, and you press a key to get final result: you loose all intermediate steps, you loose interactive use and live learning by that interactive use (for example 1/x as I showed before).

I think 7-segments display calculators have multiple values (from no, or near-no, cheating, to learning from immediate process/result).

I hate thinking in a world where high school students or college students have to do basic arithmetic by hand because someone ban all calculators. There is no reason to lost time with that basic arithmetic (it is totally a robotic job once skilled).

Of course I love my HP48 and other CAS calculators (really HP48 is lovely not for its CAS, but for a lot of other reasons). I think CAS is other step, and even more problematic.

[ddd]

yes, the fx-50FH (II) kind of has a dot-matrix display and one that's definitely good enough for cheating. In fact, I may or may not have done that a few times, so I don't really get the HKEAA's obsession with that. I guess it's not a full dot-matrix display so it's still limiting enough?

Also, for some reason the HP 15C (and 10/11/12/16C, but none of the new versions) is on the list, no idea how I forgot to mention that on a forum called "The Museum of HP Calculators", but I think it's just something they left on the list when they made it in 1991 (iirc) and never thought about, because which high school student has a HP 15C in 2020? (Me, hopefully, RPN is so much better than brackets hell where I put brackets around everything because I'm not sure how the calculator would interpret it)

[David22]

(09-12-2020 07:31 AM)ddd Wrote:  I guess it's not a full dot-matrix display so it's still limiting enough?

If it isn't modified there is no problem: there is no memory nor alphabetic capabilities in his memory.

If it is modified inside, its display can show a lot of an all type of information as it has a complete line with full dot-matrix.

(09-12-2020 07:31 AM)ddd Wrote:  Also, for some reason the HP 15C (and 10/11/12/16C, but none of the new versions) is on the list, ....... because which high school student has a HP 15C in 2020? (Me, hopefully, RPN is so much better than brackets hell where I put brackets around everything because I'm not sure how the calculator would interpret it)

HP 15C is very old, but there was a "remake" by HP aound 2011 (more speed but with a few severe bugs). And some people can use their father or grandfather HP calculator instead of buying a new and worse one

I prefer HP 15C to most actual non-graphic scientific calculators. For example HP 15C is much better than most actual Casio: it can handle complex numbers with all functions, while most Casio can't do that, even actual models listed with "Complex number support".

Of course HP 15C (al least original 15C I own) is really slow. If you run a long loop program or an integral approximation you must be really patient.

[ddd]

(09-12-2020 09:58 AM)David22 Wrote:  If it is modified inside, its display can show a lot of an all type of information as it has a complete line with full dot-matrix.

It's not exactly a full line of dot-matrix display (like a HP 30b), it's multiple rectangular dot-matrix regions that usually only contain one character (like a HP 35s)

Still, it's definitely adequate for cheating and vastly superior to a 7-segment display.

[David22]

(10-07-2020 06:57 AM)ddd Wrote:  It's not exactly a full line of dot-matrix display (like a HP 30b), it's multiple rectangular dot-matrix regions that usually only contain one character (like a HP 35s)

Still, it's definitely adequate for cheating and vastly superior to a 7-segment display.

Right, I wanted to say complete line with full dot-matrix chars, i.e., not a dot-matrix complete line, but a line completed it all with characters, where each character is full dot-matrix.

Since early times in pocket computers/calculators we saw models like HP-71b or Sharp PC-1500 with full line dot-matrix (you can draw continuous graphics, although being a very narrow line), or models like Sharp PC-1250 where you only had dot-matrix at chars level, not being capable of continuous graphics across them because there is a blank/empty column between each char (I didn't like this way, and I think hard cost would be near the same).

[Pekis]

(08-16-2020 10:39 PM)Dave Britten Wrote:  

(08-16-2020 06:59 PM)David22 Wrote:  Casio fx-5800P is the only other non-graphic programmable cal available today, but it seems graphic without being. I see no value on it: its programming model is much better than fx-50F/fx-50FH but it isn't solar and for "no solar" calcs there are much older and much better programmable calculators.

The one thing I really like about the fx-5800P is a really small detail that makes a big difference: using ?X without the STO arrow in between to prompt for a value and present the current value as default. It's similar to how INPUT works on the 32S and 42S. It's great for running a program multiple times when you only want to change some of its inputs.

Back on the subject of the fx-50FH and fx-3600P, I worked out a reasonably efficient way to replicate the Int function to get the integer part of a number. You can omit the 0>X term if you know you won't be dealing with negative values.


fx-50FH:

Fix 0:Rnd(X+.5(0>X)-.5(X>0))


fx-3600P:

Fix 0:X+.5(0>X)-.5(X>0):Rnd

Hello, so here is a "HMS+" program for the Casio fx-3650P II:

Code:


0->A:0->X
Lbl 1
?->X:Fix 0
((X>=0)-(X<=0))(250Abs(X)-Rnd(100Abs(X)-.5)-60Rnd(Abs(X)-.5))/90+A->A   
((A>=0)-(A<=0))(90Abs(A)+Rnd(60Abs(A)-.5)+100Rnd(Abs(A)-.5))/250->X
Norm 1:Goto 1

Notes:

• Rnd(X-.5) stands for INT(x) where x>0, because INT(x) is missing
• ((X>=0)-(X<=0)) stands for SGN(x), because SGN(x) is missing
• (250X-INT(100X)-60INT(X))/90 stands for HMS->DEC(x) where x>0, because HMS->DEC(x) cannot be used in programs
• (90X+INT(60X)+100INT(X))/250 stands for DEC->HMS(x) where x>0, because DEC->HMS(x) cannot be used in programs
• Input x (negative or positive) in HH.MMSS..... format
• Program displays accumulated result in HH.MMSS..... format, waiting for next x