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So far I am aware, 512Kb should be possible. https://www.hpmuseum.org/hp71.htm
So far, only 32k identified on eBay (I have 2 of them now; and searching for more).
Has anybody a 512Kb to sell?
Or 2x 256Kb?.. As big as possible.
Thanks.

You cannot add 512KB RAM to a 71B as 512KB is the entire address space and some of that is taken up for system ROMs, buffers, I/O, etc.

The largest standard (non-custom) RAM modules made for the 71B were 128KB for the Card Reader port and 64KB for the front ports.

FRAM71B modules, available several times in the past but AFAIK are no longer available, could most easily provide the maximum amount of RAM, IIRC it's about 320KB (with HP-IL module installed).

What do you need so much 71B RAM for, what is the application?

Thanks. I understand a bit better. Looks like I have more to read.
"What do you need so much 71B RAM for, what is the application?"
Nothing special in sight. Just fulling-up an arrived HP-71B (like fulling-up a PC when the board arrive = "the more the better").

(06-18-2021 12:33 PM)rprosperi Wrote: [ -> ]The largest standard (non-custom) RAM modules made for the 71B were 128KB for the Card Reader port and 64KB for the front ports.

Robert, a small nitpick, there was also 160KB Card Reader modules available. (see here), Sylvain

Vintage memory modules are expensive. A FRAM71 module is a much better investment as it also adds the capability to add ROM modules. Other things to consider are an HP-IL module, a PIL-Box, and other HP-IL peripherals.

BTW, you can add 384k (for a total of 400k) of RAM to a 71B with an HP-IL adapter.
https://www.hpmuseum.org/forum/thread-4551.html

Dave

(06-18-2021 06:45 AM)floppy Wrote: [ -> ]So far I am aware, 512Kb should be possible. https://www.hpmuseum.org/hp71.htm
So far, only 32k identified on eBay (I have 2 of them now; and searching for more).
Has anybody a 512Kb to sell?
Or 2x 256Kb?.. As big as possible.
Thanks.

The very best combination for me, the one I've been using for decades and which I refer to as a "Power HP-71B" consists of:

- HP-71B, of course, 16 Kb RAM built-in

- HP-IL ROM, for I/O and boolean functions

- Math ROM: complex numbers and operations, matrix operations, hyperbolics, Polynomial Solver, 5-level general Solve, 5-level Integrate, FFT, etc, etc.

- JPC ROM: structured programming (REPEAT..UNTIL, WHILE..END WHILE, LOOP, nested IF, SELECT..CASE), number-theoretic functions (PRIM, FPRIM, NPRIM, etc), advanced string functions (REPLACE$, etc), time-date functions, formatting function, and many many many more.

- STRINGLX LEX: essential string functions (RPT$, TRIM$, ROT$, etc)

- CMT 128 Kb RAM in the card reader port

and a couple of smaller RAM modules in the front ports, just because they're spares.

This setup provides me with in excess of 160 Kb of RAM, which for the relatively slow HP-71B is more than enough, and I've never filled the memory up despite having 100+ BASIC programs in the machine and frequently using large arrays, matrices, and strings (up to 64-Kb strings can be manipulated).

I heartily recommend you to get such a power setup and forget about "maximum RAM", your capabilities will increase much more by having the Math and JPC ROMs instead of hogging the address space with unneeded RAM, which actually might significantly slow down your machine.

V.

(06-18-2021 03:29 PM)Valentin Albillo Wrote: [ -> ]

(06-18-2021 06:45 AM)floppy Wrote: [ -> ]So far I am aware, 512Kb should be possible. https://www.hpmuseum.org/hp71.htm
So far, only 32k identified on eBay (I have 2 of them now; and searching for more).
Has anybody a 512Kb to sell?
Or 2x 256Kb?.. As big as possible.
Thanks.

The very best combination for me, the one I've been using for decades and which I refer to as a "Power HP-71B" consists of:

- HP-71B, of course, 16 Kb RAM built-in

- HP-IL ROM, for I/O and boolean functions

- Math ROM: complex numbers and operations, matrix operations, hyperbolics, Polynomial Solver, 5-level general Solve, 5-level Integrate, FFT, etc, etc.

- JPC ROM: structured programming (REPEAT..UNTIL, WHILE..END WHILE, LOOP, nested IF, SELECT..CASE), number-theoretic functions (PRIM, FPRIM, NPRIM, etc), advanced string functions (REPLACE$, etc), time-date functions, formatting function, and many many many more.

- STRINGLX LEX: essential string functions (RPT$, TRIM$, ROT$, etc)

- CMT 128 Kb RAM in the card reader port

and a couple of smaller RAM modules in the front ports, just because they're spares.

This setup provides me with in excess of 160 Kb of RAM, which for the relatively slow HP-71B is more than enough, and I've never filled the memory up despite having 100+ BASIC programs in the machine and frequently using large arrays, matrices, and strings (up to 64-Kb strings can be manipulated).

I heartily recommend you to get such a power setup and forget about "maximum RAM", your capabilities will increase much more by having the Math and JPC ROMs instead of hogging the address space with unneeded RAM, which actually might significantly slow down your machine.

V.

This looks like a very expensive setup. I'd guess the 128k RAM would cost around $400 even if you could find one. On the other hand, for $400 I'll bet someone would sell a FRAM71. With that you could add the MATH 2B ROM, a customized JPC ROM, upgrade a 1A HP-IL module, upgrade the 71B O/S to 3cccc, and have tons of RAM.

Dave

(06-18-2021 12:59 PM)Sylvain Cote Wrote: [ -> ]

(06-18-2021 12:33 PM)rprosperi Wrote: [ -> ]The largest standard (non-custom) RAM modules made for the 71B were 128KB for the Card Reader port and 64KB for the front ports.

Robert, a small nitpick, there was also 160KB Card Reader modules available. (see here), Sylvain

I've read the brochures and EduCALC catalog listings of course, but I frankly don't believe they exist. Most importantly, I don't own one, and so they don't exist in my skewed reality. Until someone can produce evidence of one, I'll continue to deny they exist (but if someone does, I'll be wanting to make an offer or course...)

I know HHP advertised a 160KB module, but are you sure CMT did as well? I'm sure HHP planned to install a 32KB chipboard inside the module case along with the 2 x 64KB modules on the same board, similar to the way the 96KB module is configured w/3x32KB. Again, vaporware...

(06-18-2021 10:18 PM)rprosperi Wrote: [ -> ]

(06-18-2021 12:59 PM)Sylvain Cote Wrote: [ -> ]Robert, a small nitpick, there was also 160KB Card Reader modules available. (see here), Sylvain

I've read the brochures and EduCALC catalog listings of course, but I frankly don't believe they exist.
I know HHP advertised a 160KB module, but are you sure CMT did as well?

Well, there's Matthias' 160k HHP module as proof that they exist.

(06-18-2021 11:28 PM)Dave Frederickson Wrote: [ -> ]

(06-18-2021 10:18 PM)rprosperi Wrote: [ -> ]I've read the brochures and EduCALC catalog listings of course, but I frankly don't believe they exist.
I know HHP advertised a 160KB module, but are you sure CMT did as well?

Well, there's Matthias' 160k HHP module as proof that they exist.

I'll believe it just after I see it in person. Which will hopefully be in late 2022, when the Alschwill meetings will likely resume.

My card-reader-port RAM module is 96KB from CMT. CMT did in fact offer up to 160KB, and I drooled over it, but 96KB is all I felt I could afford at the time. Later I added a 64KB front-port ram module. I never ran out of RAM, but I probably had it 80 or 90% full, mostly with huge data arrays. There was one project where I formed Intel Hex files up to 384KB and transferred them to the PC over RS-232; but since I didn't have enough RAM to do it all at once, I sent each line as it was formed, and a GWBASIC program on the PC tacked it onto the end of the file being built on the hard disc.

(06-19-2021 01:33 AM)Garth Wilson Wrote: [ -> ]My card-reader-port RAM module is 96KB from CMT. CMT did in fact offer up to 160KB, and I drooled over it, but 96KB is all I felt I could afford at the time. Later I added a 64KB front-port ram module. I never ran out of RAM, but I probably had it 80 or 90% full, mostly with huge data arrays. There was one project where I formed Intel Hex files up to 384KB and transferred them to the PC over RS-232; but since I didn't have enough RAM to do it all at once, I sent each line as it was formed, and a GWBASIC program on the PC tacked it onto the end of the file being built on the hard disc.

@Garth - Do you recall when or where you saw a 160KB module from CMT? I've looked (!) for evidence of a CMT 160KB module in the past but have never been able to find a brochure, or ad or even a catalog listing. EduCALC carried all the CMT modules from when they were introduced until they dropped all the 71 stuff in 1990 and there never was a 160KB module listed. I have some CMT ad sheets as well as original copies of CMT's "Hand-Held Solutions" newsletters that list all their memory products and none of them list the 160KB module.

While it may have existed, it seems there would be some evidence of it... somewhere...

(06-19-2021 01:24 AM)rprosperi Wrote: [ -> ]

(06-18-2021 11:28 PM)Dave Frederickson Wrote: [ -> ]Well, there's Matthias' 160k HHP module as proof that they exist.

I'll believe it just after I see it in person. Which will hopefully be in late 2022, when the Alschwill meetings will likely resume.

It would definitely be doable with the second generation HHP sub-assemblies that use 32K SRAMs, with those they put a SRAM and the control chip on both sides of the board, probably the only thing that stopped them from making a 192K module is the stack was probably too thick.

Paul.

(06-19-2021 02:00 AM)rprosperi Wrote: [ -> ]@Garth - Do you recall when or where you saw a 160KB module from CMT? I've looked (!) for evidence of a CMT 160KB module in the past but have never been able to find a brochure, or ad or even a catalog listing. EduCALC carried all the CMT modules from when they were introduced until they dropped all the 71 stuff in 1990 and there never was a 160KB module listed. I have some CMT ad sheets as well as original copies of CMT's "Hand-Held Solutions" newsletters that list all their memory products and none of them list the 160KB module.

While it may have existed, it seems there would be some evidence of it... somewhere...

Silvain's link has it as the CMT-CR-160R; but you're right— I can't find it in the few EduCALC catalogs I kept either, or in Elek-Tek catalog I kept, or in the CMT magazines I kept. Obviously an HHP one existed, since someone had one and posted a photo of it, so maybe the CMT one was never actually sold and I was either remembering the announcement of one never made, or remembering the HHP one.

Maybe this picture helps: On the box 160K is written and on the plastic cover of the module too

(06-19-2021 01:24 AM)rprosperi Wrote: [ -> ]

(06-18-2021 11:28 PM)Dave Frederickson Wrote: [ -> ]Well, there's Matthias' 160k HHP module as proof that they exist.

I'll believe it just after I see it in person. Which will hopefully be in late 2022, when the Alschwill meetings will likely resume.

(06-18-2021 04:51 PM)Dave Frederickson Wrote: [ -> ]

(06-18-2021 03:29 PM)Valentin Albillo Wrote: [ -> ]The very best combination for me, the one I've been using for decades and which I refer to as a "Power HP-71B" consists of:

- HP-71B, of course, 16 Kb RAM built-in

- HP-IL ROM, for I/O and boolean functions

- Math ROM: complex numbers and operations, matrix operations, hyperbolics, Polynomial Solver, 5-level general Solve, 5-level Integrate, FFT, etc, etc.

- JPC ROM: structured programming (REPEAT..UNTIL, WHILE..END WHILE, LOOP, nested IF, SELECT..CASE), number-theoretic functions (PRIM, FPRIM, NPRIM, etc), advanced string functions (REPLACE$, etc), time-date functions, formatting function, and many many many more.

- STRINGLX LEX: essential string functions (RPT$, TRIM$, ROT$, etc)

- CMT 128 Kb RAM in the card reader port

and a couple of smaller RAM modules in the front ports, just because they're spares.

This setup provides me with in excess of 160 Kb of RAM, which for the relatively slow HP-71B is more than enough, and I've never filled the memory up despite having 100+ BASIC programs in the machine and frequently using large arrays, matrices, and strings (up to 64-Kb strings can be manipulated).

I heartily recommend you to get such a power setup and forget about "maximum RAM", your capabilities will increase much more by having the Math and JPC ROMs instead of hogging the address space with unneeded RAM, which actually might significantly slow down your machine.

V.

This looks like a very expensive setup. I'd guess the 128k RAM would cost around $400 even if you could find one. On the other hand, for $400 I'll bet someone would sell a FRAM71. With that you could add the MATH 2B ROM, a customized JPC ROM, upgrade a 1A HP-IL module, upgrade the 71B O/S to 3cccc, and have tons of RAM.

Dave

I agree with Valentin, that would also be my preferred set-up plus a small LEX I have added to the STRINGLEX, we all have our favorites, buckle up for feedback on that one let’s see them..

Ideally JPC, MATH (1 or 2) and the lex would be in a 64k EPROM, which is in planning, need access to the P01, and have a plan once the pandemic gets under control.

Today I have them in several different configurations
- 2*32k Port-RAM with a small MLCC cap to “keep them alive” when switching to another machine
- CMT-HHP-FRAM versions in the card reader port.
- JPC/MATH eprom I found on eBay here in Germany, another enthusiast separated from his “loved toys”, which was my luck.

Maybe I can build a 160k as the one Matthias has, I recall that there is a description which gets me halfway there… another one for the “rainy day-list”

Thanks again to Sylvain for the amazing Compendium - @FLOPPY, this is one you can enjoy for days if you’re into understanding what the 71B is capable of!

Thanks for all the replies guys.

Clearly, the MoHPC time-proven method of getting info is at work here:

A. "Does anyone know XYZ?" => Crickets....

B. "XYZ does not exist!" => Nearly instant proof that XYZ does exisit.

As for CMT's 160KB module, it has been claimed in the past, more than once, that this model did exist, but I was never able to find proof, even after lots of searching. I am guessing what happened is CMT announced that they would be making one of these, since HHP already had one available, but projected low sales due to extremely high cost (the 128KB module cost $500) led CMT to abandon the idea and then never actually introduced it.

Hello Girls and boys,
I will get my Multimods and was thinking somebody would step in and offer me via privat message any xxxxxxKb RAM for the front ports (this is like tuning: you put a 12cyl engine on a 2CV. it makes sense? not really. But for the fun, if we can do it, we make it). you see the engine outside the engine compartment? (for example the RAM would be outside the HP71B in an arduino or other?), nobody care as long the power go to the wheels. price? the ECB print the money = not an issue.
The HP71B in my possession has 2x32kB + 4kB RAM.
Thanks for all exchanges and people sharing my thoughts (sorry, I can make few programs in python-fortran-pascal-java-c-pygtk-tkinter-java-HP41 but no electronic circuitry).

(06-19-2021 04:21 AM)Garth Wilson Wrote: [ -> ]Silvain's link has it as the CMT-CR-160R; but you're right— I can't find it in the few EduCALC catalogs I kept either, or in Elek-Tek catalog I kept, or in the CMT magazines I kept.

Hi,

This is "out of left field", however I felt I should ask - which edition(s) of the Elek-Tek catalog(s) do you actually have? I am still missing at least seven of them to complete the collection of scans for the PPC archive. The ones currently missing are editions 1, 2, 4, 6, 8, 9, 32 and 34 or higher.

Thanks,
Jake

(06-21-2021 06:12 PM)Jake Schwartz Wrote: [ -> ]This is "out of left field", however I felt I should ask - which edition(s) of the Elek-Tek catalog(s) do you actually have? I am still missing at least seven of them to complete the collection of scans for the PPC archive. The ones currently missing are editions 1, 2, 4, 6, 8, 9, 32 and 34 or higher.

I remember numbers on earlier ones, but I can't find a number on this one. It looks like the attached picture. I liked Elek-Tek's prices, but otherwise favored EduCALC. I think the only thing I bought at Elek-Tek was my first 71 (and that was a lot of money back then!). When I realized I should have kept more catalogs, it was too late. They had been thrown out. Fortunately I did keep a few EduCALC catalogs.