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HDB-DOS in a Rom Pak?


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I have a question about Drivewire (HDB-DOS) in a Rom Pak.


I recently rescued a Coco3 and burned the HDB-DOS 1.4 to an EPROM, and put it in a Super Pitfall cartridge. This boots up OK, except I find it's unstable- I can't boot NitroOS, and even the RAM stress test fails on bank $03c. However, if I pull the cartridge and instead load with cassette port, it works fine.  It seems like the cartridge is interfering with RAM.  


Is this just a known limitation of running HDB-DOS from a Rom Pak, or do I need to modify the cartridge in some other way?

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On the CoCo, a DOS is intended to be loaded based on a signature in the ROM, whereas a game (like Super Pitfall) uses a different mechanism to autostart. I'm not 100% sure on the technical details of why HDB-DOS isn't working in your configuration, but I suspect that if you had the same ROM image loaded in a non-autostart cartridge (e.g. the Deluxe RS232) things might work better for you.

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Most disk software is not worried about the interrupt from the cart ( autostart ..ie the q signal to cart ) so you have to fix any writes to ff23 .

Also if you want the coco3 basic working properly it might be best to let it do its boot up routine and run your cart with the exec &HE010.  Formally &HC000 on coco1,2


Also you new pcb's for your roms !  They are cheap ..work better .. i even have some that can bank switch.allowing 32k of data for coco1,2 ... 

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  • 5 months later...

I've designed a multibank card for my COCO2 and I tinker a bit with drivewire.


I've flashed "HDB-DOS 1.1D DW3" in one bank of my card and got it working, but I also have some instabilities.

Sometimes the computer freezes when loading a game and I need to go through a power cycle to bring it back and then the same game can load wihtout an issue.


I have a jumper to enable /disable autostart, I will give it a try.

However I'd like to know where I can find the latest HDBDOS version for Drivewire.

I've been following the links from here and only found v1.1d : https://www.cocopedia.com/wiki/index.php/Getting_Started_with_DriveWire



Edited by YannAros
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