|Re: you lucky devil|
Message #20 Posted by Diego Diaz on 13 Sept 2008, 10:35 p.m.,
in response to message #19 by Egan Ford
I'll try to shed some light on the obscured parts of Clonix/NoV's utilization that you've pointed out.
First, the overall burning process has been simplyfied since this very morning, when I published the Windows configuration utility. Please take a look at it. I think this will turn Clonix/NoV's user's life quite more easy. However, this preliminary version does not support Bankswitching.
...BTW, NoVRAM has another feature. If you do not have HP-IL and you want to get ROMs into RAM, you can burn 4K in a free 4K page of NoVRAM, then from the 41CX transfer the page to RAM. E.g. for PPC this would be a multi-step process:
Burn HEPAX+PPCL to NoVRAM.
Put in 41CX, copy PPCL to a free even page, say, A (10).
Burn HEPAX+PPCU to NoVRAM.
Put in 41CX, copy PPCU to matching odd page, B (11).
You can save a couple of steps in the procedure above, just remember that you can load *both* PPCL and PPCU images (or any other 8K module) into NoVRAM Flash ROM in a single burning. Then COPYROM to HEPAX RAM.
Just don't forget to re-configure your NoVRAM in order to remove the Flash ROM copy of the PPC, Otherwise you'll have tow copies of PPC inside your NoVRAM, wasting 8K of ROM storage.
If you copy a complete ROM into the HEPAX ram, with the HEPAX software leave it alone? The HEPAX documentation indicates that there are a few bytes in the ROM that have to be set a specific way so that the HEPAX software knows to leave it out of the HEPAX storage space (chain). If you copy an entire ROM into HEPAX ram, these bytes would most likely be set to something different. In that case, it seems the HEPAX software, upon the next HEPDIR command, would attempt to put the memory space being occupied by the ROM back into the file chain. Anyone know?
These few words (remember HP-41 memory does not use bytes but 10 bits words instead) you have to change to tell HEPAX that a particular page is no longer part of its File System, are required if you want to free this RAM page, *without* loading any ROM image into it.
If you place a ROM image into any HEPAX RAM page, HEPAX will see it as a *real* ROM Pac plugged into your HP-41 and , consequently, will leave it alone.
...am I to assume I can't put Advantage onto a NoVRAM unless I wipe out the HEPAX? I find this a bit confusing.... Frankly, the only advantage I see to NoVRAM over Clonix is if one maintains the HEPAX so as to access all of that RAM....
Certainly, NoVRAM adds two extra ROM pages to the HEPAX functionality, while Advantage requires three pages. Thus it is physically impossible to fit Advantage .ROM images into NoVRAM ROM while HEPAX emulation is loaded. However, you can still configure your NoVRAM in Clonix-like fashion and burn Advantage into it.
Note that Advantage is the *only* HP ROM Pac that uses Bankswitching (IR Printer also does, but this is a peripheral, not just ROM).
The USB emulation in the WinXP VM is impeccable--I have never yet had a USB device that my XP on Mac arrangement can't recognize. I am glad to hear the burner is a USB device. The downloadable manual does not seem to make this clear, and I thought I would need to scrounge some older PC machine with a parallel or serial port. USB-Parallel and USB-serial adapters (good ones) are not cheap and don't always work.
I'm curious to see if the WinXP VM manage to handle the configuration utility and the programmer software. I have not a Mac environment to test, and know of some other Mac users that will also be interested in this scenario.
USB to serial converters will not work at all with the serial programmer, this has been proved without doubt. Certainly the USB programmer is the way to go.
I need to repeat that the clonix and novram manuals are highly technical and if I take the leap I will be back here seeking the really simple version of all this.
Writing good manuals is not one of my best qualities... :-) As I got deep understanding of every technical aspect from the inside, it's somewhat difficult to figure out which parts may require a more detailled explanation from a user's point of view. However, both manuals are becoming outdated and are in need of a deep revision/rewriting in order to make an easy to use reference document.
In general a module can use 1 or 2 4K pages. If more is required, then bank switching is used. (I have not heard that term since my Apple ][ days). 12K modules are banked switched, AFAIK, NoVRAM/HEPAX do not support the same page toggling between images. An interesting experiment would be to see if a 12K ROM image could be and used as 3 4Ks.
I think some sort of glossary will help here.
Page: a 4096 words (10 bits each) addressable space in which HP-41 organize its memory
Module: Any physical Memory device that can be plugged into HP-41 system. They can have one or more pages.
.ROM file image: a 8192 bytes file that contains one (4096 words) HP-41 page image. 4k modules require one 8k .ROM file image, while 8K modules require two.
Lower (L) and Upper (U) images: Convention for the designation of the pages in 8K (or more) modules. L images must be loaded into an even numbered page and the corresponding U image of the same module must be loaded in the inmediate following odd page.
Bankswitching: (Also called the HP-41 black-beast... ;-) An internal procedure that allows some (few) modules to use the same HP-41 system page to share more than one of this module's ROM pages. Note that the Bankswitching is an *internal* mechanism of the module itself, and it's fully transparent to the HP-41.
In fact, HEPAX and NoVRAM ROM does support Bankswitching as the HEPAX module itself is heavily Bankswitched (it uses four banks into the same page). However as there are only two extra pages and the only Bankswitched module requires three pages, there is no way to use the Bankswitching capabilities.
Regrettably, trying to run Advantage into three different pages won't work. You can take this for sure... :-(
Hope this has helped to clarify a bit the mess.
As usual, feel free to post or mail me with any comments, questions or suggestions you may have.
Best wishes from the Canary Islands.