[Coco] CocoSDC disk format

Bob Devries devries.bob at gmail.com
Sun Nov 30 20:03:48 EST 2014


I have now successfully created a working boot disk image for CocoSDC. 
Here's how:

I created an empty disk image using HxD (there are probably other ways 
also) of $4800 bytes long. I put that image in the second slot of the SD 
card (drive 1), and then booted with the boot disk from the NitrOS9 repo.

I set the dmode of the /SD1 descriptor to 1024 tracks, 1 side, 18 
sectors per track. Then I formatted it.

I created a directory called BOOTMODS on /DD, CHD'd to it, and used 
modbuster to extract all the modules from the existing working OS9Boot 
file. I used "ls >bootlist" to create a text list of module names, and 
then used minted to add the modules I needed (Rammer, R0, CoWin etc) and 
removing the bootlist filename.

I then used the OS9Gen command to create the OS9Boot file on the /SD1 
drive "OS9Gen /sd1 <bootlist". I believe that this method will work to 
over-write an existing OS9Boot file, but watch out for fragmentation!

After adjusting the startup.cfg file on the SD card using notepad on 
Windows, and re-inserting the SD card in the CocoSDC, I was able to boot 
with my new modules.

Any questions? :P

Regards, Bob Devries
Dalby, QLD, Australia


On 1/12/2014 8:29 AM, Christopher R. Hawks wrote:
> On Mon, 01 Dec 2014 07:52:47 +1000
> Bob Devries <devries.bob at gmail.com> wrote:
>
>> I am using KwikGen, and sometimes OS9Gen.
>>
>> The data in LSN0 is correct; it points to the new OS9Boot file.
>> However, the new boot track ends up in the wrong place. OS9Gen errors
>> out if the OS9Boot file is fragmented; not sure how KwikGen handles
>> it that situation.
>>
>> Regards, Bob Devries
>> Dalby, QLD, Australia
>>
>>
>
> 	Does os9gen error out if you give it the -e flag?? It should if
> the file is fragmented and you don't give it the '-e' option...
>
>
>
>> On 1/12/2014 7:28 AM, Robert Gault wrote:
>>> Bob Devries wrote:
>>>>
>>>> <snip>
>>>> Currently the boot track is placed at offset $0264 sectors by the
>>>> NitrOS9 build.
>>>> This is correct for a single-sided disk. It boots correctly. All
>>>> attempts by me
>>>> so far to build a new boot track have failed. Also a new OS9Boot
>>>> file appears to
>>>> be ignored. This part I cannot understand.
>>>>
>>>
>>> How are you trying to build the new boot track? How did you build
>>> new OS9Boot files? If you are merging modules to create new OS9Boot
>>> files, you need to use ded to alter LSN0 so that bytes $15-$17
>>> point to the first byte of the file and bytes $18-$19 indicate the
>>> size of the file. Dir -e will give you the size of your new OS9Boot
>>> files but you can't use the location given by dir. You must use ded
>>> to go to the sector given by dir, find the actual start address,
>>> and check to see that the boot file is not fragmented.
>>>
>>> Robert
>>>
>>>
>>
>
>
>
>
> Christopher R. Hawks
> HAWKSoft
>


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