[Coco] CoCoSDC under NitrOS9

David Ladd davidwladd at gmail.com
Thu May 31 01:48:57 EDT 2018


Dave,

I myself would have used the "os9" utility from the Toolshed Project.  You
could have created the formatted disk image with it and written the
boot/kernel track to the correct offset for use with the CoCoSDC.  Then
after that you could have copied your OS9Boot file to the new disk image
and then used the kwikgen tool to link the LSN0 to the OS9Boot file.  Then
used dsave to copy the rest of the files over to the new disk image.

I have used the "os9" utility a few times to create some test boot disks
for use with both the CoCoSDC and DriveWire. :D



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On Thu, May 31, 2018 at 12:15 AM, Dave Philipsen <dave at davebiz.com> wrote:

> Well, I started with Allen’s 128 MB image and I used a binary editor under
> Windows and expanded it to 1 GB.  Then I put the dsk file on the SD card
> and mounted it.  From OS9 I dmode’d the descriptor for /sd1 and changed the
> # of cylinders from 007F to 07FF.  Then I formatted it (OS9 format verified
> the size of 4+ million sectors before I started the format).  Then I did a
> cobbler /sd1 which correctly copied the boot file to it but had an error
> because it couldn’t correctly write the boot track.  Then I put the SD card
> in a reader and started diddling around with a binary editor in Windows.
> The boot track always resides at the logical position of track 34 (sector
> $264??) so I found the boot track on the 128 MB image (starts with the
> letters ‘OS’ or $4F53).  I copied the boot track out of the 128 MB image
> and into the 1 GB image.  You have to remember that even though the boot
> track gets put at the same offset (sector $264??) the disk allocation map
> is different because the 1GB image uses 8 sectors/cluster instead of one.
> So you have to manually calculate where to set the bits in the allocation
> map so the operating system won’t overwrite the boot track.
>
> Anyway, I’m just going mostly by memory but I guess I could do a write-up
> describing exactly how I did it.
>
> http://www.davebiz.com/images/1GB.jpg
>
>
> Sent from my iPad
>
> > On May 30, 2018, at 7:05 PM, Travis Poppe <travispoppe at gmail.com> wrote:
> >
> > I'm curious how you managed the 1GB bootable VHD?
> >
> >> On Tue, May 29, 2018 at 3:33 PM Dave Philipsen <dave at davebiz.com>
> wrote:
> >>
> >> Thanks to Allen Huffman I've been running a bootable NitrOS9 image on my
> >> CoCoSDC for some time now.  Recently I increased the size of the image
> >> and I now have a bootable 1GB partition for NitrOS9.  So now I would
> >> like to be able to mount and unmount images from NitrOS9.  Does anyone
> >> if any documentation exists for the CoCoSDC (short of disassembling the
> >> SDC DOS) that would facilitate me in writing some utilities under
> >> NitrOS9 for this?
> >>
> >> Dave
> >>
> >>
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> >>
> >
> >
> > --
> > Travis Poppe
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> >
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>
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