I was the one who suggest the ROM may have been altered based on the fact fact that Eighty One doesn't produce the display artefacts as posted earlier in the thread and at the time no-one could produce a genuine H4th EPROM for comparison as opposed to copies that seem to be derived from the emulator. In recent times that has been rectified as I found someone who did have the genuine article and indeed the emulator code matched the real thing C/W the aforementioned maths bug and display problems, so my conclusion was that Eighty One cures the Inverse right hand column display error in the same way that the new replacement ULAs do although no-one seems to have an explanation of how that is being achieved.kpalser wrote: ↑Mon May 18, 2020 1:58 am I’ve been trying to contact David Husband to ask permission to use the Forth ROM in my emulator. I’m no longer sure who I should be asking. I’ve read the other threads in this group and the above replies regarding the offsets.
The fact that David / Skywave Software would have gone on to write Forth ROMs for the BBC micro and CPC without being challenged by the copyright seems odd.
But then on the other hand you have Bob Alsum / Tree Systems with his Pluri-Forth ROM, where he has in the past released the source code: https://www.timexsinclair.com/?s=Bob+Alsum and the ROM screen offsets seem better suited to NTSC.
Maybe one was licensed to the other. I’m going to try and contact both authors with the key aim to get permission to include the ROM but maybe also determine who did what.
Regarding the ROMs themselves there seems to have been suggestions that they may have been modified for EightyOne. But identical files are found in the beta distributions of Xtender 2 with file dates a good 5 years before the version history of Eightyone.
As for Husband not being challenged I can only assume he did it legally under licence as the original manual, as opposed to some online copies, openly credit Bob Alsum's work.
Regardless of the copyright message H4th displays the similarities to the US version are so marked that in my opinion (and I stress it's only my opinion) the UK version is something done under licence as opposed to totally original work. Compare the the two ROM images in Eighty One (H4th/Treeforth) if they are VASTLY different in every way then I happily withdraw the above.
It should be noted that Pluri-forth ,I believe, was previously known as Multi-forth and Tree-forth so you may want to search for the origins of that in regard to earliest incarnation/creator etc.
Who owns the rights to the IP contained within H4th?
It's now getting on for nearly forty years since its inception and things that were slated for production such as the floating point co-processor didn't see the light of day as far as I know so perhaps when added to the fact that Forth was seen by a majority as a dead language as it didn't lend itself to playing nice colourful games, which is what most people wanted to do rather than real computing, perhaps then the UK licence holders due to lack of interest let the licence lapse and therefore Bob Alsum or his descendants/employers whoever, are the IP owner.
Other than that ask any of the emulator authors or project developers on this forum or the German forum who have used the EPROM code in their works, how they went about seeking permission to use thirty odd year old code if indeed they did at all or perhaps check out the accompanying read me files for a given emulator or project that no doubt credits/acknowledges the various owners of the IP rights to ROM code contained therein.
Standby alert 