[Coco] NitrOS9 question

[camillus gmail]

Hi Dave,

Following your quest, I thought of something. First of all I do not have any knowledge on OS9 / NitrOS9, but maybe the modules you load have to be on a certain boundary. Kind like a sector is always 512 Bytes, no matter if you put in two bytes. 

Could it be that OS9 being a more sophisticated OS have this scheme. Would explain that only one byte longer would crash things. Seems to me that the memory allocation functions needs to be disassembled and checked out to see how a loading of a module takes place.

Just a thought, I could be completely wrong.

cb
On 10/7/2017 4:52:17 AM, Dave Philipsen <dave at davebiz.com> wrote:
Ok, I compiled a minimum headless OS9Boot file that should boot with a
shell on T2 as my terminal. The size of the bootfile is $42F8. When I
try to boot with it, as expected, it fails. I get the banner text from
Init and Sysgo. Interestingly, sometimes when it boots I also get a
string printed to the screen that says, "WHAT?"

Now I use dEd and simply iddle the file length to $4401 and manually
clear out the extra data to all zeroes. Voila! NitrOS9 boots and I get
the shell prompt on my terminal! If I diddle it one byte shorter to
$4400 it will not boot. So it apparently matters only that the length
of the file is $4401 or longer.

Another interesting point: If I diddle the file length of OS9Boot even
greater to $8000 it still boots but smap reports way less system
memory. So that tells me that the system memory allocation is based
upon the size of the OS9Boot file, not its actual contents. Apparently
no check is made to the contents of the file or whether it contains
'non-modulized' data!

Dave


On 10/7/2017 2:48 AM, Neal Crook wrote:
> My guess is that it will make no difference. If it does, experiment 2 is to
> pad with 0xff. I await the result with interest.
>
> Neal.
>
> On 7 Oct 2017 08:04, "Dave Philipsen" wrote:
>
>> That would be an interesting experiment. I’ll see if I can try that this
>> weekend.
>>
>> Dave
>>
>>> On Oct 6, 2017, at 11:12 PM, Barry Nelson
>> com> wrote:
>>> What happens if you just pad the end of the OS9Boot file with zeros?
>>>
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