help 64k disk

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help 64k disk

Post by .mad. » Tue Apr 23, 2019 11:10 am

Please can someone tell me the correct command-line (MAME / Xroar) or poke to enable 64k in DDOS.

i can not get this game to load.
is it broken?.

i can get 64k TAPEs working in Dragon64 typing EXEC to get a blue cursor.
but DDOS seems disabled with this command.

any help welcome. :mrgreen:
Brocks Kingdom (198x)(PSE)[!].vdk
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Re: help 64k disk

Post by robcfg » Tue Apr 23, 2019 12:16 pm

Thing is, you cannot have 64k and DragonDOS at the same time, as the rom overlaps part of high memory.

I remember there is a way to enable/disable the DragonDOS cartridge, but I don't remember how.

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Re: help 64k disk

Post by pser1 » Tue Apr 23, 2019 4:18 pm

I think that in the archive ther exist some 'anti-DOS' programs.
IIRC there is a "DOSMATE" created by Steve Evans that can be loaded from a Basic program and when executed it detaches the DOS
and calls the binary program we want to start. This program is responsible for switching to MAP1 in order to access the whole 64k
I think we have used it in some games that refused to work properly with attached disk controller and it works perfectly

Ps try this link ...

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Re: help 64k disk

Post by .mad. » Tue Apr 23, 2019 6:44 pm


i still can't get that game to load.
i *think* it requires DDOS to load the other parts of the game after the boot program has disabled ddos.
so maybe only ok for single load files.

this program looks like it could do the job, but i need to get it on a disk image to load and test it.

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Re: help 64k disk

Post by snarkhunter » Wed Apr 24, 2019 7:36 am


I think it is still possible to directly address the WD2797 chip after disabling DOS on a Dragon computer. I seem to remember a friend of mine creating such routines back then, so he could load pieces of code that would require the whole RAM, including the DOS memory pages. He might have done so on the "Ket Trilogy", but I'm no longer sure about this (to be checked on my previously uploaded VDKs, if that one was part of those).

[Edit] ... after checking the forum and finding the thread I had in mind, it appears this was a very different trick for "TKT" (loading the code from disk as a big chunk of raw data, disabling the DOS, then relocating the code at proper RAM locations and resetting the BASIC pointers so it would then execute as a standard BASIC program). But I know he did address the direct loading from disk after disabling the DOS, which must be somewhere in our extensive correspondence (which is several hundred pages spread over several years).


Kind Regards,

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Re: help 64k disk

Post by .mad. » Thu Apr 25, 2019 5:28 pm

Thanks for the info.

After a lot of searching...
i now know that the game disks with filename extension .64k from Pulser and P.S.E., require DISCUP from the same company.
It moves the disk workspace out of the graphics pages back to their original postion.

it comes in 3 flavours
Dragon DOS
Super DOS / Dragon DOS 4

wait for motor to stop
type EXEC
it displays a RED cursor.
insert game disk with .64k files

EXEC &H200 will clear Discup out of memory and detach DOS

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