[Coco] Multiple HDB-DOS 256 drive partitions Software Wanted

[Boisy Pitre]

There hasn't been a partitioning table feature done as far as I know on the CoCo.

Actually, there is enough unreserved space in RBF's LSN0 to allow for some limited partitioning, but no one has attempted to commandeer that area for anything.

Merci,
Boisy





On Apr 24, 2013, at 12:25 PM, Bill Gunshannon <billg999 at cs.uofs.edu> wrote:

> 
>> On Wednesday 24 April 2013 10:53:55 Mark Marlette did opine:
>> 
>>> Luis,
>>> 
>>> I don't believe this is correct.
>>> 
>>> In the current configuration of  the NitrOS-9 offset is 0 and works as
>>> you say but.....
>>> 
>>> If you were to add an offset to the SuperDriver descriptor it would then
>>> use that as it's relative LSN0 offset.
>>> 
>>> The size / drive geometry then kicks in to effect and you go up from
>>> there.
>>> 
>> There is a bit, IIRC in the IT.TYP byte of the descriptor, and I miss
>> typed
>> in the previous nsg & called it IT.DNS, my bad!
>> 
>> See the superdriver descriptor doc you have on your site, which tells
>> format whether it should query the drive for its geometry and size, or
>> should take the descriptor info as gospel.  For a virtual floppy, my /sh's
>> IT.TYP is $81, but READ the docs!
>> 
>> THIS BIT IS THE MOST DANGEROUS MINEFIELD IN NITROS9.
>> 
>> Read, and set the bits in each device descriptor very carefully else you
>> may format the whole drive with a MB script.
>> 
>> YOU HAVE BEEN WARNED!
>> 
>> With this bit properly set, and the offsets in the descriptor properly set
>> so its safe to format based on the descriptor, you can do anything you
>> want. One could theoretically setup the first partition at 120 megabytes
>> so
>> it would only need a 1 sector per cluster FAT map, then setup the next
>> 41,287,680 bytes of the disk as 256 hdbdos virtual floppies, then do the
>> next 120 megs as a 2nd os9 partition, then by poking new values into
>> HDBDOS, have another 41,287,680 byte piece of the drive as vdisks 257-512,
>> and repeat that several more times on a 1Gib disk.  All accessable at the
>> same time with nitros9 if you have enough /sh-like descriptors in the
>> bootfile, each properly configured, with even the 257-xxx hdbdos vdrives
>> being bootable with the use of my bootlink utility.
>> 
> 
> Wow...  This reminds me so much of Ultrix-11.  Absoluteley nothing
> actually on the disk to tell you what the partitioning is.  If you
> chose to do non-standard partitions and then moved the disk to a
> different system, pfftttt.  All gone.  Take the warnng above very
> seriously,  :-)
> 
> bill
> 
> -- 
> Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
> billg999 at cs.scranton.edu |  and a sheep voting on what's for dinner.
> University of Scranton   |
> Scranton, Pennsylvania   |         #include <std.disclaimer.h>
> 
> 
> 
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