The Museum of HP Calculators

HP Forum Archive 14

[ Return to Index | Top of Index ]

Message #1 Posted by Matthias on 18 Jan 2004, 8:38 a.m.

I have a empty Rambox on which I would like to write the W&W Rambox system. The image of the system is now on the digital tape, but now.. How do I get it onto my machine? I tried it with my CY, on which I set the Rambox, but the stupid thing always copys the image on the internal Rabox of the CY and not on the external. I can not deactivate the CY´s Rambox, cause there is the READPG command I need to copy...

Any suggestions?


Re: Rambox
Message #2 Posted by Werner on 19 Jan 2004, 9:45 a.m.,
in response to message #1 by Matthias

Hi Matthias,

I just came back from holidays and after long internet abstinence ;-) I found your question here.

Please better do not use your Eramco RAMbox together with your HP-41CY as there may be a conflict of the two layers of RAM, the internal W&W-RAM and the external Eramco-RAM. So maybe you cannot address the external RAM by your HP-41CY. Maybe with some advanced MCODE routine an addressing of all RAM will be possible but AFAIK at the moment such aroutine is not available.

So, instead of the HP-41CY I would propose to use your Eramco RAMbox together with one of your HP-41C/CV/CX. This should work without problems.

FIRST, please replace the dead buffer battery in the card reader housing of the Eramco-RAMbox by a new one. If not, you will lose the "soft" operating system again by every removing of the RAMbox from the HP-41. I do not know the Eramco RAMbox, but maybe there is an internal dip switch that ensures "write protection" for the pages that normally carry the soft-OS. The W&W-RAMbox has such an internal dip switch. If you want to load the OS into the protected area or if you want to use all 64k of RAM you should set the dip switch to "write enabled" throughout your OS loading procedure and back to "write protected" afterwards. Maybe you will have to make some first experiments with the right switch positions.

Now you can begin with the loading process of the RAMbox OS into your empty Eramco RAMbox. For this you should use your HEPAX-Module (you own at least the "STD HEPAX", this module is fine for use here). Please plug your HEPAX into port 1 (not into port 3 or 4) of your HP-41CX and switch the calculator on. After that the HEPAX ROM should be relocated to page 6. Switch off the calc again and plug in your Eramco-RAMbox (card reader housing, so port 4). After having switched on the calc again, HEPAX should have initialized all 32k of the prioritized first Eramco RAM block. You can test this by using the HEPAX QROM Catalog (XEQ"HEPAX" 002). There you should see "HEPAX RAM" at all QROM/ROM pages 8-F.

Now plug in your HP-IL module into port 3 (IMPORTANT: before, please deactivate the IL-printer ROM by the dip switch of the IL module in order to avoid an "ILL CONFIG"). Now use "READROM" function of the HEPAX twice to load the W&W-RAMbox OS-A to page 8 and also to page C.

Now use PG<> to switch into the second 32k RAM block. This block is still without OS, so there might happen a non-critical hang-up of the calc which can easily be removed by ENTER/ON (halfnut version) or removing/replacing the battery (fullnut version). Now switch off and on the calc again to initialize the HEPAX-RAM of the second 32k block. You have to repeat the above mentioned steps but this time with OS-B. So, use again HEPAX function “READROM“ twice to load the W&W-RAMbox OS-B (!) to page 8 and also to page C.

Now remove your HEPAX module from the HP-41 (of course only possible if you have removed your Eramco-RAMbox first as the card reader housing blocks port 1. You see, it is important that the RAMbox has a working buffer battery! But there may be an alternative: You certainly also own a port extender. You can plug this into port 3 and maybe use it for connecting HEPAX and IL modules externally. I do not know if this is a healthy configuration as I do not own a port extender but you can make some own experiments here).

After you have removed the HEPAX and have reconnected the RAMbox with the loaded ROM images at pages 8 and C, the W&W-OS should be visible in your HP-41CX. If you use CAT 2 you will see "-RAMbox 64b" once or twice. If you see it only once, page 8 or page C had been part of the real HEPAX RAM during the READROM process and was removed (and deleted) while removing the HEPAX module. This is why you had to carry out READROM twice (to pg#8 and to pg#C). HEPAX RAM cannot cover the whole 32k address space of the Eramco RAMbox, so only either pg#8 or pg#C were covered.

Now you have to find out where your remaining OS is located, at pg#8 or pg#C. There are different ways how to do this without HEPAX module but for you I would propose to use the CCD-ROM because you own this module and then it is the easiest way:

Use CAT 8-F of the CCD-ROM (CCD ROM in port 2 or 4 ! In case of port 1 or 3 it may hide the W&W-OS at pages 8 or C).

If the OS is located at page C, I would copy (e.g. with COPYPG, see below *) it to page 8 and delete the one at page C. You only need the OS at page 8 but it also works fine at any other even page.

After that please use PG<> to switch to block A. There repeat the copy and delete procedure so that your OS-A is only at page 8.

If you want to copy your OS from pg#C to pg#8 without HEPAX but the W&W-RAMbox-OS itself, you first had to alter the W&W-OS with the HEPAX. As long as you have not removed your HEPAX you can easily use its HEXEDIT function to change both 10-bit-words of W&W-OS-A (and W&W-OS-B) at ’nFFD’ and also at ’nFFE’ to any other value than ’17’ (hex), e.g. to ’00’ (this is necessary because ’17’ prevents using COPYPG to self-copy the own W&W-OS).

At last you should open your Eramco-RAMbox again and set the dip switch back to “write protected“, so that you cannot erase the OS by accident. But I am not sure if the Eramco RAMbox has such an internal switch because I only know W&W-RAMbox.

I think the described steps should be adequate for completely loading an Eramco RSU-2 (with soft block switching) with the W&W-OS like you want. Of course sometimes some own additional experiments are needed to find the final solution. I hope I could help you to load it and wish you luck for your trial !

Best regards from Darmstadt/Germany,


Re: Rambox
Message #3 Posted by Matthias on 20 Jan 2004, 8:22 a.m.,
in response to message #2 by Werner


I tried Werner´s instructions step-by-step but my HEpax couldn´t find page A-F (NO ROM).This could be a problem of the dips in the rambox I do not know, what a re they for. One seems to be a write-protection, but which one? And for what is the other? See my pictures below. Perhaps someone has more informations about this box (Memory size for example).

[] [] []

Re: Rambox
Message #4 Posted by Matthias on 20 Jan 2004, 10:42 a.m.,
in response to message #3 by Matthias

Sorry, wrong links

[ Return to Index | Top of Index ]

Go back to the main exhibit hall