[Coco] NitrOS9 question

Barry Nelson barry.nelson at amobiledevice.com
Sat Oct 7 12:03:06 EDT 2017


> Neal Crook
> Sat Oct 7 07:27:45 EDT 2017
> 
> That sounds completely reasonable. Memory is allocated based on the module
> header declaration.. there's not really any way (or reason) to look inside
> the module and determine whether its content is valid/reasonable  (and no
> need for you to zero-out the unused space). In fact you  probably need not
> change the size of the bootfile blob at all.. just the header declaration
> for the last module. Caveat: assuming you have crc checking turned off (as
> it is by default)
> 
> Neal

I don’t think he changed the module data at all, just the file length and added extra bytes (zeros) at the end of the file. The fact that this worked may indicate an issue with the CoCo boot boot loader he is using to load the OS9Boot file into memory initially. I think if the file is the wrong length it is not loading all the data. I am talking about the “stage 0” boot here. On a normal floppy, this would be the data the DOS command loads from track 34 into ram at $2600, but he is not booting that way, he is using CoCo boot, which I think loads OS9Boot without reading track 34.



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