HP-71B: 82490A or 82441A

[smp]

Hello all,

I am happy to have a good working HP-71B in my collection.

One of my hobby things is to get the Forth language working on each of my vintage computers. I understand this is achievable with the HP-71B: one needs to acquire the 82441A Forth/Assembler ROM. Of course, these occasionally become available, usually for an outrageous sum on eBay (a recent link: http://www.ebay.com/itm/Forth-Assembler-...true&rt=nc).

I also understand that there is another route: acquire the 82490A 41CV Translator ROM. These also occasionally become available, sometimes for a somewhat less outrageous sum on eBay (http://www.ebay.com/itm/391234244435?_tr...EBIDX%3AIT).

I understand that the 82441A ROM is available in order to specifically make the HP version of the Forth language available, but I also understand that the HP version of Forth is also fully available in the 82490A ROM.

My question to the group is this: If I were to drop an outrageous sum of money to acquire one of these ROMs, which one should I choose? My desire is only to be able to use the HP version of the Forth language. I really do not intend to use the assembler in the 82441A ROM or the 41CV translator in the 82490A ROM.

Is one of these obviously "better" that the other? Is the 82490A ROM more limited in any way? Do both ROMs have the same capabilities?

Your thoughts and advice are very welcome.

smp

[Joe Horn]

(08-26-2015 01:29 PM)smp Wrote:  One of my hobby things is to get the Forth language working on each of my vintage computers. I understand this is achievable with the HP-71B: one needs to acquire the 82441A Forth/Assembler ROM. ...

I also understand that there is another route: acquire the 82490A 41CV Translator ROM. ...

I understand that the 82441A ROM is available in order to specifically make the HP version of the Forth language available, but I also understand that the HP version of Forth is also fully available in the 82490A ROM.

My question to the group is this: If I were to drop an outrageous sum of money to acquire one of these ROMs, which one should I choose? My desire is only to be able to use the HP version of the Forth language. I really do not intend to use the assembler in the 82441A ROM or the 41CV translator in the 82490A ROM.

Is one of these obviously "better" that the other? Is the 82490A ROM more limited in any way? Do both ROMs have the same capabilities?

The following quote from page 74 of the HP-41 Translator ROM might be helpful:

Quote:Relation to the HP-71 FORTH/Assembler ROM

The FORTH system contained in the HP-41 Translator Pac is very similar to that in the HP 82441A FORTH/Assembler ROM. The HP-41 Translator Pac does not contain an assembler, but its built-in word set contains additional floating-point words and other HP-41 words not found in the FORTH/Assembler ROM.

The floating point words in the HP-41 Translator Pac differ from their FORTH/Assembler ROM counterparts in two respects:

• The HP-41 Translator Pac words will error if any of their arguments are alpha data.

• The HP-41 Translator Pac words perform a stack lift only after computation is finished, so that the stack is unaffected if a word terminates due to an error. In the FORTH/Assembler ROM, the stack lift is performed before the computation.

FORTH words defined from words common to both modules can be compiled into either system from a text file containing the definitions. However, because the addresses of built-in words and user variables are not the same in the two systems, you should not attempt to exchange files of type FORTH between the systems. That is, a file originally created as FORTHRAM by the FORTH/Assembler module should not be renamed as FTH41RAM for use with the HP-41 Translator Pac, and vice-versa. The most likely result of such an exchange is the Memory Lost error.

Bottom line: If all you want to do is play with Forth on the '71, and not assemble Saturn code nor use the HP-41 translator's unique features, then I'd suggest getting whichever is cheaper, since their Forths are almost identical.

By the way, you can freely download both as ROM images (they are both on this LIF-disk image), and install either one in a IRAM, if you own a PIL-Box, and if you can FREE a big enough IRAM to hold the ROM image.

[Dave Frederickson]

(08-26-2015 02:19 PM)Joe Horn Wrote:  By the way, you can freely download both as ROM images (they are both on this LIF-disk image), and install either one in a IRAM, if you own a PIL-Box, and if you can FREE a big enough IRAM to hold the ROM image.

That collection of LEX files only contains one ROM image for Workbook71 and copying the FORTH ROM image to an IRAM won't work because FORTH needs the hard-coded portion of the ROM. This can be done with FRAM71 or either of the two emulators.

The ROM image for the FORTH/Assembler can be downloaded from J-F Garnier's website or hpcalc.org.

Dave

[smp]

(08-26-2015 02:19 PM)Joe Horn Wrote:  The following quote from page 74 of the HP-41 Translator ROM might be helpful:

<...snip...>

Bottom line: If all you want to do is play with Forth on the '71, and not assemble Saturn code nor use the HP-41 translator's unique features, then I'd suggest getting whichever is cheaper, since their Forths are almost identical.

By the way, you can freely download both as ROM images (they are both on this LIF-disk image), and install either one in a IRAM, if you own a PIL-Box, and if you can FREE a big enough IRAM to hold the ROM image.

Hi Joe,

Thanks very much for your response! This information is very helpful.

I have not yet experimented with any emulator - that sounds like a great way to try things out first.

smp

[smp]

(08-26-2015 03:21 PM)Dave Frederickson Wrote:  

(08-26-2015 02:19 PM)Joe Horn Wrote:  By the way, you can freely download both as ROM images (they are both on ... <...snip...>

That collection of LEX files only contains one ROM image for Workbook71 and copying the FORTH ROM image to an IRAM won't work because FORTH needs the hard-coded portion of the ROM. This can be done with FRAM71 or either of the two emulators.

The ROM image for the FORTH/Assembler can be downloaded from J-F Garnier's website or hpcalc.org.

Hi Dave,

Thanks to you, too, for this information.

I am not familiar with FRAM71. Is this some sort of add-on RAM device? What's the difference between FRAM71 and IRAM?

Thanks,
smp

[Dave Frederickson]

(08-26-2015 04:51 PM)smp Wrote:  I am not familiar with FRAM71. Is this some sort of add-on RAM device? What's the difference between FRAM71 and IRAM?

Yes, FRAM71 is an add-on memory device designed by Hans Brueggemann that can configured for up to 392K of RAM. Like any soft-configured RAM device, it can be configured as IRAM. Unlike any other RAM device, it can also be configured as ROM. The downside is that there're only about 20 FRAM71's in existence.

I encourage you to get on the waiting list for the next batch.

Dave

[Marcus von Cube]

(08-26-2015 04:51 PM)smp Wrote:  I am not familiar with FRAM71. Is this some sort of add-on RAM device? What's the difference between FRAM71 and IRAM?

FRAM71 is a device created by forum member Hans Brüggemann. It fits the card reader slot of a 71B and provides non volatile RAM in 'gigantic' amounts (512 or 1024 KB, depending on hardware version). It is configurable and the maximum RAM available with a given configuration depends on what else is plugged into your 71B.

IRAM (Independent Random Access Memory) is just RAM memory that the 71 can address as a port. The FRAM71 can provide IRAM as explained above.

[Joe Horn]

(08-26-2015 03:21 PM)Dave Frederickson Wrote:  

(08-26-2015 02:19 PM)Joe Horn Wrote:  By the way, you can freely download both as ROM images (they are both on this LIF-disk image), and install either one in a IRAM, if you own a PIL-Box, and if you can FREE a big enough IRAM to hold the ROM image.

That collection of LEX files only contains one ROM image for Workbook71 ...

Oops, I meant the Forth lexfiles, not ROM images. However, neither of those lexfiles would help because:

(08-26-2015 03:21 PM)Dave Frederickson Wrote:  ... copying the FORTH ROM image to an IRAM won't work because FORTH needs the hard-coded portion of the ROM. This can be done with FRAM71 or either of the two emulators.

The ROM image for the FORTH/Assembler can be downloaded from J-F Garnier's website or hpcalc.org.

Aha! Good to know. Thanks, Dave!

[smp]

Dave and Marcus, thanks very much for your explanation of FRAM71.

How do I get on the waiting list for one of these? Just send a PM to Mr. Brüggemann?

smp

[Marcus von Cube]

(08-26-2015 06:49 PM)smp Wrote:  How do I get on the waiting list for one of these? Just send a PM to Mr. Brüggemann?

I'm pretty sure he will reply to a PM.

[smp]

(08-26-2015 07:26 PM)Marcus von Cube Wrote:  

(08-26-2015 06:49 PM)smp Wrote:  How do I get on the waiting list for one of these? Just send a PM to Mr. Brüggemann?

I'm pretty sure he will reply to a PM.

Thanks again, Marcus. I've sent a message to him.

smp

[rprosperi]

(08-26-2015 01:29 PM)smp Wrote:  My question to the group is this: If I were to drop an outrageous sum of money to acquire one of these ROMs, which one should I choose?

Generally speaking, the 41 Translator variant is more rare and as a result, more expensive.

My suggestion is to search for complete HP-71B systems; many such systems have a Forth/Assembler (or 41-Translator) ROM included and often can be bought for less than the price of the standalone ROM listings, which are generally aimed at collectors (as the prices prove).

Also, there were many programs, tips, hints, etc. for HP-71 Forth submitted to the PPC Computer Journal, CHHU and HPX newsletters in the late 80's; by coincidence, I've been researching some of these exact articles recently. A DVD with all those issues (plus a ton more) is available from Jake Schwartz here. Strongly recommended for all fans of classic HP Calculators.

[smp]

(08-27-2015 12:34 AM)rprosperi Wrote:  

(08-26-2015 01:29 PM)smp Wrote:  My question to the group is this: If I were to drop an outrageous sum of money to acquire one of these ROMs, which one should I choose?

Generally speaking, the 41 Translator variant is more rare and as a result, more expensive.

My suggestion is to search for complete HP-71B systems; many such systems have a Forth/Assembler (or 41-Translator) ROM included and often can be bought for less than the price of the standalone ROM listings, which are generally aimed at collectors (as the prices prove).

Also, there were many programs, tips, hints, etc. for HP-71 Forth submitted to the PPC Computer Journal, CHHU and HPX newsletters in the late 80's; by coincidence, I've been researching some of these exact articles recently. A DVD with all those issues (plus a ton more) is available from Jake Schwartz here. Strongly recommended for all fans of classic HP Calculators.

Hi Bob,

Thanks very much for your thoughts.

Since I already have a good working HP-71B, I was not considering acquiring another one. Those that have come up for sale containing some of these special ROMs seem to go for high prices, too, because of folks like me who know what they are looking at and then drive up the bid accordingly. Sigh.

Thanks also for the pointer to that treasure trove of information. I will be looking into that.

smp

UPDATE: Whoo Hoo! I have now made it to become a Member!