[Coco] NitrOS9 question

[Gene Heskett]

On Saturday 07 October 2017 07:27:45 Neal Crook wrote:

> 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
>
Or you could use my vfy, which will fix the header parity and crc in one 
swell foop while adjustingthe size of the memory.  Its a swiss army 
knife about that stuff.

> On 7 Oct 2017 10:52, "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 <D>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
> >
Actually in a normal system, system memory is used up by the number of 
devices each needing a $27 byte long table for each path descriptor. 
With 2 or more of each style in my boot files, I'm so low on sysram that 
I've not been able to actually format a floppy in a decade. All I can do 
is delete everything on it including the boot track if I want to make a 
new boot.

> > 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" <dave at davebiz.com> 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
> >>> <barry.nelson at amobiledevice.
> >>>
> >>> com> wrote:
> >>>> What happens if you just pad the end of the OS9Boot file with
> >>>> zeros?
> >>>>
> >>>> --
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> >>>> Coco at maltedmedia.com
> >>>> https://pairlist5.pair.net/mailman/listinfo/coco
> >>>
> >>> --
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> >
> > --
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> > Coco at maltedmedia.com
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Cheers, Gene Heskett
-- 
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