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

[Kip Koon]

Never let it be said that a Coco user can't do something.  I have always
believed in the ingenuity of the Coco users in our community.  You guys have
really made a difference in the Coco world.  You kept it going and believed
in it long after the rest of the world dropped the Coco by the way side.
Even I thought the Coco community had died out until about two years ago.
Let's try and figure out a way, some way to make all this work to our
advantage and finally make multiple partitions really work both in NitrOS-9
and HDB-DOS rom images.  I know we can do this.  I've seen what amounts
essentially miracles having taken place in the Coco arena since I've been
gone.  Here are some serious thoughts to this end.
Isn't there extra rom in the rom image to implement more features like
reading a partition table pretty quickly before the initialization of
recognizing the beginning of a 256 virtual floppy drive partition block
outside of a basic program doing it for us?  Something very similar to what
is used in the Partition table in the MS-DOS & Windows world.
Also someone very recently in this thread said that there is some empty
space of LSN0 that can be "commandeered" for a partition table of some kind?
How much space is actually available?  It seems to me that a byte would be
needed for the file system type - FST;  three bytes for the beginning LSN -
BLSN0, BLSN1, BLSN2; and three bytes for the ending LSN - ELSN0, ELSN1,
ELSN2.  That would be seven bytes so far.  
Is there any other features or characteristics that need to be represented
that can't be encoded in the FST byte itself?  Some ideas to mull over.
I'd also like to see some identifying markings of some sort on every type of
Coco disk.  Since many of the formats don't have identifying marks
representing the format used, let's make some.  After all, we are the only
ones in the entire world (as far as I know) that still use the Coco, love
her and care for her - our beloved Coco!
Kip

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Brett Gordon
Sent: Thursday, April 25, 2013 8:32 PM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Multiple HDB-DOS 256 drive partitions Software Wanted

Oh, bummer!   I was hoping for a PC style partition table, or any style
partition table that would support more than two operating systems.  I was
also hoping too hard that this data would be stored on the disk itself
rather than in ROM ( like a volume carrying its own metadata ).   Sorry, it
seems my "what if" and "geeze whiz... that would be cool"  must have
mis-translated this thread!   :)


On Thu, Apr 25, 2013 at 5:09 PM, Robert Gault <robert.gault at att.net> wrote:

>
>
> The partitions referred to in this thread should not be confused with 
> PC hard drive partitions. HDBDOS and RGBDOS split a hard drive into 
> two sections based on three bytes in the Disk ROM. These bytes, 
> $D938-$D93A, give the address of the first Disk Basic sector on the 
> hard drive. There is no indication on the drive itself that sectors 
> differ on either side of this "border".
>
> The sectors can be any size in bytes and that is a function of the 
> hard drive, hardware or emulation. Regardless of the sector sizes, 
> Disk Basic can only use 256 bytes per sector. The rest will be wasted 
> unless unless the ROM is modified to work with pseudo sectors. OS-9 
> can do this but there is not enough room in the Disk ROM to compensate 
> for alternate size sectors. Only the first 256 bytes will be used.
>
> All emulators use 256-byte sectors.
>
>
>
> --
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> Coco at maltedmedia.com
> http://five.pairlist.net/**mailman/listinfo/coco<http://five.pairlist.
> net/mailman/listinfo/coco>
>



--
Brett M. Gordon,
beretta42 at gmail.com

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