???41cx = 42s????

Howdy from Fort Worth.

I have a 41cx which I just recently picked up and I would like to give it as much functionality as a 42s. Is this possible?

I have a Math 1 module, a Adavantage module (on the way), and a PPC module (on the way).

What else do I need for this machine? Will the X-Functions module provide extra memory? I realize the CX already has the x-functions built in, but can it still use the extra memory.

Does the Advantage module have all the same math funtions as the Math Module? If so, I guess I wouldn't need it? Correct?

The 42 has more memory (I can never match it). It also has the Solver. Do any of the modules contain the equivilant of the Solver.

Any info would be appreciated.



I wouldn't try to make the 41cx equals the 42s. To me the 41 is already greater than the 42


That is great and all for those you have used these machines at lenght, but for us newbies who wish to learn about them, could you be more specific?



The Advantage is arguably the most important module HP produced for the 41 series. It includes solver and integration FUNCTIONS (rather than PROGRAMS like the old Math Module). The Advantage also has a lot of matrix functions and a bunch of other useful stuff.

I don't have a Math Module handy so I can't do the comparison you asked for, but I think you will find it little used if you have the Advantage.

Depending on how you use the 41, you may want to add the extended memory. It doesn't work like main memory - it's more like a disk drive, though there are ways to get around that. I used (my 41CX is currently NOP) extended memory for storing little used programs that I could download, use, then purge, without having to rely on having my card reader handy.

Have fun with your new toys.



No need to add XFUNCTIONS they are already built in, just add XMEMORY modules. The PPC rom is more of a systems/hacker oriented device. Lots of fun.

The 42S has a larger program space becuase it has no removeable memory. Get the 82104A card reader and you can load and save programs. Also get an 82143A printer.



as other people in this thread already stated,
get one or two X-Memory modules,
which will add several hundred registers to your already built-in 124 X-Memory registers (sums up to 600 XM-regs) .

Furthermore, the most advanced *HP* module is the Advantage Pac, which includes powerful matrix functions, and has a numerical solver.
AFAIR is has a numerical integral function, too, but I'm not sure at the moment.

However, one of the most advanced modules in general is the CCD module, which extends the HP-41 user interface by many new features, and the CCD module lets you do synthetic programming like it were normal programming!

BTW:The matrix functions in the Advantage Pac were taken from the CCD module.

The PPC module was a milestone in functionality when it came out, and it's history showed how many people could work together on such a project.

Nevertheless, I'd sell or swap away the PPC module for a CCD module,
since it's functionality cannot be compared with the power of the CCD module (OMHO),
unless you want to keep the PPC for sentimental reasons,
like I do;-)

Back to the main theme:

A 42S has many more features than a 41, especially regarding the user interface (menus, graphics,...).
But it has it's disadvantages, like no I/O, only output.

Apart from that, the 42S could be compared to the HP-41CV w/o X-Memory features.
I write this because main memory and X-Memory in the HP-41 are to different pairs of shoes, at least from the user's point of view.

In the 42S, you 'only' have main memory, but some more than in the HP-41.

So if you have HP-41 programs which use XM, you'll have to rewrite them for use in the 42S.




I can use extended memory for storage...what about a quad memory ROM...can it be used for even more storage?




The quad memory ROM is only good for a 41C. The 41CV and 41CX have that memory built-in.

With two X-Mem + Advantage + PPC, you will have a very well outfitted rig. FYI, my 41CX has two X-Mem + Advantage. The last port I used for swapping printer, card reader, Surveying, and Structural Engineering. I never bought a PPC ROM, but I borrowed a friend's for about a month.




One other point Joe may be interested in--the 42S is much faster than the 41. Four times I think.

I use a 42S as my primary calculator. However, it never completely replaced my 41 until the 41 stopped working. I also have a 48G+ that I use for certain things, but the 42S is just easier.

I finally figured out what HP should be working on for us: a PDA/Scientific/Graphics calculator. I envision something about the size of two 42S hinged together like a Sony Clie. The bottom half would be a scientific calculator keyboard and the top half would be a 320x480 color screen. Keys should be like the 41 series (alpha on sloped face). Actually, how about swappable keyboards (scientific, business, qwerty) offering different capabilities, and the ability to handle either the Palm OS or Pocket PC? Stuff it with a high-speed PDA processor, 64MB+ RAM, backward compatiblity with ALL programmable HP calcs (e.g. HP-55 mode, HP-34C mode, etc.), RPN keystroke programming combining 41/42S/32SII, RPL, etc and you've got something I would pay $500-$1000 for.


Joe --

I provided a more-detailed answer to most of these questions several days ago in this Forum, but here's a synopsis:

1. The Math module has RPN programs for hyperbolic functions, triangle solutions, and Fourier analysis that the Advantage module does not have. The same set RPN programs for complex-valued operations is implemented on the Advantage module. Everything else on the Math module (e.g., matrix operations, solve, integrate) is implemented in a much more sophisticated fashion on the Advantage module.

2. The 41CX will not recognize an X-Functions module. So, the module would not provide 124 extra registers of X-memory to a 41CX. However, each X-Memory module (limit of 2) would add 238 registers of X-memory.

3. X-memory is like a RAM disk on a PC, not like extra RAM. Some programs/ROM functions can access X-memory directly, but generally, X-memory is like built-in external storage that requires battery (or capacitor backup) power.

4. Memory modules is useless on the 41CX; it already has the maximum 320 registers. DOn't get one.


Brief summary:

  • You can't plug an X-Functions/X-Memory ROM to an HP-41CX,
    it won't be recognized and actually it does conflict with the
    already built-in X-Functions set.

  • You can add up to two X-Memory RAM modules to your 41CX.
    Doing it will carry your 41CX to its maximum RAM
    configuration, unless you plan to add external RAM
    using EPROMs, etc.

  • Unless you need (slow) Fourier transforms, the Math ROM
    is absolutely useless next to an Advantage ROM, which
    has a lot more functionality, and most of it in the
    form of ultra-fast, memory-saving *machine-code
    keywords*, instead of slow, inefficient *user-code

  • Contrary to general belief, the PPC ROM isn't just
    a bunch of dated software to do synthetics, which has
    been superseded and made obsolete by later ROMs, such
    as the CCD ROM. Far from it, the PPC ROM was conceived
    as a toolkit ROM, where you would find hundreds of very
    useful routines, highly optimized for speed and
    convenience, in all cathegories from finance, to matrix
    handling, to calendar-printing, to multi-function
    plotting. All of them documented in incredible detail,
    with plenty of useful, no-nonsense examples, and lots
    of hints and tricks to maximize efficiency.

    That you can't find in any other ROM, be it the CCD ROM,
    the Advantage ROM, or any other you care to mention.
    The point is, synthetics are but a minor aspect of the
    PPC ROM. Just have a look at its manual when you get it
    and you'll see it for yourself at once.

    Myself, I have my 41CX fitted with the Advantage ROM, the
    PPC ROM, and an X-Memory RAM, with the free port used
    mostly for the Card Reader. And trust me, that's a
    combination that even a 42S would find very hard to surpass.


What would be great is a freeware and fast HP-42S emulator for PDAs ;-)


(emulators already exist, but the HP-42S ROM is not free)


You used a PPC module? What are some of its capabilities?



1) the ppc rom gives you a way to pop into a rom at any line you want to - not just at global labels.

2) it can also let you turn your 41 into a small piano tuned in (roughly) thirds. kind of chinese.

3) many surveyors look(ed) at extended memory as data storage for 299 coordinate pairs. the only bad thing is that:

3 and a half) hp never wrote an extended function to transfer data files directly from extended to mass storage. you can do that with ascii files though. it's like hp thought someone would be writing the great american novel on his 41 and storing it in 4k chunks on his data casette but he wouldn't be doing math or anything. go figure.


I'm fan of the HP-41CX.

Recently I got a HP-42S, a great machine, but it have the following disadvantages:

- Typping texts needs to press 2 keys per caracter.

- No I/O (bar code reader, card reader, Modules, etc.)

- You cannot reconfigure the keyboard. With the HP-41 you are "the owner of the keyboard" and it is one of the best features you can ask for!

I should say that the HP-42S is the better calculator I know to operate with matrix and complex numbers. Very friendly, better than HP-15C, HP-28C/S, HP-48.




Somewhere in the '98 I was thinking about what can be done with the existing HP-48 hardware. Emulation of some of the greatest HP calcs like HP-41C, HP-42S and HP-71B seems very interesting to me and I decided to investigate if it will be possible to develop and implement a true emulation of these machines.

I started with HP-41 emulator and after a few months of hard work I had a working version of HP-41E.

Then I decided to test what are the limits of HP-41 emulation and after a year I had an HP-41 emulated monster (HP-41X) on HP-48GX with 4096 registers, 16-characters display, plenty of ports and modules (CCD, XF/XM, HEPAX, Advantage, PPC ROM, ZENROM, Math, Stat, ...), >3x speed, printer and card reader support and many other advanced features.

The next step was to develop an HP-42S emulator (HP-42X) with 96K RAM, two "ports" with almost 32K each, printer support and the ability to load/save programs.

After this, it was a matter of time to write HP-71 emulator (HP-71X). Now it is finished and the specifications are: 129.5K RAM (ports 0..3), MATH ROM, Forth/Assembler ROM, HP-41 Translator Pac and great part of JPC ROM included, card reader support, printer support, etc, etc.

All of them can be installed at once on HP-48GX with two RAM cards.

Basically what I have proved is that a stock HP-48GX with RAM cards can emulate the HP-41, HP-42 and HP-71 (all expanded to their maximum physical and logical limits) without problem and that an HP-48GX calculator can be turned into a monster which can execute thousands of HP-41/42/71/48 programs. And if I can do this, HP can do this, only if they want. I don't see a problem for them to make a new HP-41C, HP-42S or HP-71B, based on the same old HP-48GX hardware. Saturn has still enough power to make all of them work very fast and reliable ...

Best regards.


HrastProgrammer wrote: >>>And if I can do this, HP can do this, only if they want. I don't see a problem for them to make a new HP-41C, HP-42S or HP-71B, based on the same old HP-48GX hardware.<<<

No, Hrast, you are wrong! If you can do it, this does not mean that (the new) HP can do it! No doubt that the old HP could do it!

May this be a challenge to (the new) HP, if anyone of them is following the moHP posts. Do the HP calculators nowadays mean to them anything at all (as HP's still mean to us and as HP's meant to them during the years that have passed)?



Even though it's been perhaps 20 years since I used the PPC ROM, I can actually answer your questions--I happen to have a copy of portions of the manual, including the table of contents. Even if you don't use the PPC ROM much, the manual is worth the price of admission. It's an incredible piece of work.

The PPC ROM contains 122 global labels. The manual includes a table with the routines grouped by function (see below; I have also included a few examples for each category).

* Alpha Register (e.g. Alpha to Memory; Substitute Character)
* Block Operations (blocks of storage registers--e.g. Block Move; Insert Record)
* Curtain (memory curtain--e.g. Curtain Finder; Curtain Up)
* Display (display settings--e.g. Recall Display Mode)
* Key Assignments (e.g. Clear Key Assignments; make Multiple Key Assignments)
* Load Bytes (six routines for synthetic programming--e.g. Load Bytes; Flag Inputs for Load Bytes)
* Mathematics (e.g. Curve Fit; Complex Arithmetic; Fractions<###>; Next Prime; Solve; Integrate)
* Matrix (e.g. Interchange Rows; Multiply Row by Constant…but no complete matrix solvers)
* Memory (some more synthetic-useful routines--e.g. .END. Finder; Open Memory)
* Miscellaneous (e.g. Calendar Date to Julian Date and vice versa; Tone N)
* Non-Normalized Numbers (e.g. Character to Decimal and vice versa; HEX to NNN and vice versa; HEX to Decimal)
* Peripherals (e.g. Barcode Analyzer; Column Print Formatting; High Resolution Histogram; PPC Logo)
* Program Pointer (some more synthetic-useful routines--e.g. Alpha Store b; Count Bytes)
* Return Stack (RTN stacks are limited, these routines work around that--e.g. Lengthen Return Stack; Shorten Return Stack)
* Sorts (e.g. Stack Sort; Large Array Sort)

### I used the fraction routing as the core the Feet-Inches-Fractions program I posted on this site a while back. Search under the 41 programs it you're interested.

Some of the PPC ROM was superseded by XFUN (or 41CX), Advantage, CCD, and perhaps others, but--as I mentioned above--the manual is worth it even if you don't use the module.

I hope this helps,



Many years ago I actually wrote some XMEM->Card and Card->XMEM routines for two programs I was working on--COGO-Coordinate Geometry (for surveying calculations) & HC-Hardy Cross Water System Network Analysis). I never finished COGO, but the routines I did complete work. I finally figured out that to do what I wanted, it would take hundreds of manhours and more memory than you can put in the machine (I don't like uploading/downloading subroutines with the card reader). Plus, I have a nice computer program to that work. The Hardy Cross program is simply an improved version of the program in the Civil Engineering Solution book.




Sorry about the formatting of the previous message. It looked like bullet points on screen, but I forgot that some formatting is lost when posting.



I drive an old pickup, use a fountain pen and wear a mechanical watch...and use a 20 year old calculator. As you can see speed isn't an issue with me! :)


Hi; if you allow me to...

I like to use the [pre] in the begining of a text block I want to keep the line spacing and line feed. Then, a [/pre] at the end closes it. See:

if I simply type

and post it, it will read

one two three.

Instead, I use:


and it looks like this:


I posted it because I think this is somewhat easy to remember (pre, from preformated text).

Hope this helps


Thank you for your kind words, Nenad :-)

We really should discuss a little about HP, calculators, past and future ... but I have lost your phone number you sent me last year :-(

Best regards to all ...


You wrote:

" I should say that the HP-42S is the better calculator I know to operate with matrix and complex numbers. Very friendly, better than HP-15C, HP-28C/S, HP-48."

I think you should try an HP-71B + Math ROM. I own
all the models you mention, and for fast, friendly, easy
manipulation of complex numbers and even very large
matrices, nothing beats an HP-71B+Math.

You can have more than 400 Kb for your largest matrices
(versus 7 K or 32 K for an HP-42S),
and you can operate with them at blinding speed and with
the upmost ease that BASIC language provides. Just for
instance, this is all you need to do to solve a linear
system of N equations with complex coefficients, including
prompted input and formatted output:


you don't need a program for it, you could key in those
instructions right from the command line and would be
able to recall them an edit them at will. That you can't
do with an HP-42S, unless you write a program.

What's more, if your coefficients are physical
measurements and 12-digit precision isn't justified,
you can define all matrices as COMPLEX SHORT and save
a lot of memory, allowing for much larger matrices.
That you can't do with an HP-42S either.

Finally, you can store both data and result matrices
in DATA files within the machine, in binary or plain
ASCII format, for further processing,
sharing with other programs or I/O. The HP-42S has no
provision for data files of any kind.

As for complex variables, you can deal with them as if they were
normal, real variables. Defined functions can take complex
parameters, and you can define complex variables and
matrices in two precisions, thus saving memory. For

     COMPLEX SHORT A(10), B(10)
MAT A=SIN((2,3)+(4,5)/(6,7))*A

would declare three complex vectors, two full-precision
and one memory-saving short-precision, would prompt for
A & B elements, then would multiply all elements in
A by the constant Sin((2+3i)+(4+5i)/(6+7i)), and it would
finally add all complex elements of A and B, store the
result in C, and print it. All at full speed, and
from the keyboard.


Thanks you for your complete description of the HP-71B features.

During my years of studying Electrical Engineering I dreamed with the HP-71B. But I never could see one except the superb brochure I own until today.


Guillermo wrote:

"During my years of studying Electrical Engineering I dreamed with the HP-71B. But I never could see one except the superb brochure I own until

Actually, they were incredibly inexpensive a few years ago,
when a large British government organization cleared some
25,000 of them. They were so overabundant and inexpensive that you could
get one with an HP-IL ROM for just $30 or so, even some
unused ones were available. People attending one of
the Annual Meetings organized by HPCC at the time were
given one for free !

Now that all those 25,000 are already sold out, it's not
so easy, but if you are into Electrical Engineering, I
would confidently advise you to get one, there's no better
machine for that purpose in the whole world, it has all
the features needed for Electrical Engineers, namely:

- up to 512 Kb addressable space, i.e: up to 448 Kb of
internal RAM

- with a Math ROM: full set of matrix operations, working
for both real and complex one- and two-dimensional
arrays and matrices

- with a Math ROM: full set of complex variables and
functions (arithmetic, trigs, logs, exponentials, etc),
all useable in calc-mode, from the command line, and
in programs, including using them as parameters or results from
user-defined functions and subprograms

- with a Math ROM: Solve and Integrate keywords, which
can accept user-defined multi-line functions, and
can call themselves recursively, so allowing solving
systems of non-linear equations, multidimensional
integration, and integration/solving of implicit

- Fourier transforms and inverses, using the extremely
speedy Fast Fourier Transform (FFT) algorithm.

- subprogram capability, passing parameters by reference
and value, and recursively. Same for multi-line, user-
defined functions. Whole matrices can be passed as
parameters, if needed.

- Full I/O, using the HP-IL ROM, which can control up to
3 different HP-IL loops at a time, with many devices
on each, including printers, tape drives, disk drives,
HP-41Cs, other HP-71Bs, etc, at speeds up to 5,000 bytes
per second.

- file system in RAM, allowing multiple programs and
binary/ASCII data files, as well as binary suprograms
and LEX (Language EXtension files) which add new
keywords to the resident BASIC, or even new languages
altogether, such as Forth/Assembler

- Incredibly powerful ROMs available, such as the Math
ROM, the Forth/Assembler ROM, or the Circuit Analysis
ROM, as well as the HP-41C Translator/Forth ROM.

... and many other advanced features, all in an
extremely portable, solid, rough, quality handset. Get one,
you won't regret it !



yep. thats the downside of programming: if you don't use it 20 times a day then a really tight and elegant program will probably take more time to write than it will save. sometimes it's fun though.

fortunatly; a lot of the things i do are either simple or one of a kind so i haven't been bitten by the write-a-program bug in about 4 years.


Does the 71b have an actual 41c/v/x emulator on a ROM?



Thanks Luiz…I keep forgetting how to format things here. That's what happens when you're over 40!



With me, the urge to program comes and goes…kind of like how I get a cold once a year or something!



It does have an HP-41C Translator ROM, which allows you
to key in HP-41C/CV/CX programs right from the keyboard,
or load them from some HP-IL device.

The translator implements most functions and functionality
in the mainframe HP-41, plus most functions from the
X-Functions ROM and one or two basic ones from the Timer
ROM. Being a translator and not an emulator, there are
some things that can't be translated or don't translate
well, but generally speaking, most 'normal' programs can
be translated, or created anew. No synthetics at all, of course !

The translator has some extra advantages. For once, it
does include a complete Forth-language system, so with
the ROM installed you can write programs in either BASIC,
HP-41C user code (RPN), or Forth. The Forth system also allows
you to define 'new' HP-41C functions for use in your
HP-41 translated programs. It also gives a much larger
set of registers (up to SIZE 999 at least, I think) and
translated programs run much faster than in the real 41C,
average 7 times faster, and with greater precision (12 digits vs. 10).

Finally, you can use it right from the keyboard to perform
RPN calculations, with the classical 4-level plus LastX stack.


I know what you mean.... I'm 41!

Wanna know a little secret? I got most of my memories back when I took my studies back and I found out that I should have my Master's Degree (Brazillian post-graduation first tittle) to be accepted as a University teacher. Boy, what a hell-of-a job! And today's students force you to keep your brain cells up-to-date...

And life goes on...

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