[Coco] CocoSDC booting OS9

[Gene Heskett]

On Tuesday 18 November 2014 11:14:04 Brett Gordon did opine
And Gene did reply:
> See inlines, below
> 
> On Tue, Nov 18, 2014 at 9:49 AM, Bill Pierce via Coco
> 
> <coco at maltedmedia.com> wrote:
> > I run all my systems (real and emuled) the way Robert describes. Even
> > my starter kits are set up this way (I modded the roms with the
> > offset).
> > 
> >  I have been complaining for almost 4 years now that a 2nd set of
> >  hdbdos roms needs to be generated with the ofset at $5A000 and got
> >  nothing but flack. Now it's slowly coming back on everyone :-)
> 
> Cool... its nice to know there is some sort of standard HDB offset.
> 
> > Even the stock Vcc 1.4.2 and it's accompanying vhd (which needs to be
> > updated to NOS9 v3.3.0) is set like this. This is s atandard set by
> > Alan deKok when he developed the emudsk driver for the Coco
> > emulators. SuperIDE uses a different offset, and needs to be sat
> > different. It's the only odd case I know of.
> 
> I have a SuperIDE, and with the development of CoCoBoot, I know I have
> it set to stock, and have set it a million times to:  0x52ddc .  This
> seems to be another more-or-less standard.  Of course to modernize the
> two systems,  Disks should probably have a actual on-disk (meta)
> partition table... PC's have had partition tables for 40 years... why
> don't we?

We do, but it isn't on the drive, its in the drive descriptor as wpc and 
ofs, signifying the starting address in LBA sectors as a 3 byte value.

There IS empty space in LSN0 to do that, but to use it would take a major 
rewrite of the rest of the nitros9 system.  The descriptor works well.

> > If the roms could become available with the offset, then a copy of
> > Robert's RGBDOS/HDBDOS Tools disk needs to accompany the roms as
> > they allow you to use the auto boot feature to boot straight into
> > OS9 or RSDOS.
> 
> I'll have to check out Roberts utilites they sound fun!
> 
> > Bill Pierce
> > "Today is a good day... I woke up" - Ritchie Havens
> > 
> > 
> > My Music from the Tandy/Radio Shack Color Computer 2 & 3
> > https://sites.google.com/site/dabarnstudio/
> > Co-Webmaster of The TRS-80 Color Computer Archive
> > http://www.colorcomputerarchive.com/
> > Co-Contributor, Co-Editor for CocoPedia
> > http://www.cocopedia.com/wiki/index.php/Main_Page
> > E-Mail: ooogalapasooo at aol.com
> > 
> > 
> > 
> > 
> > -----Original Message-----
> > From: Robert Gault <robert.gault at att.net>
> > To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> > Sent: Tue, Nov 18, 2014 8:52 am
> > Subject: Re: [Coco] CocoSDC booting OS9
> > 
> > Brett Gordon wrote:
> >><snip>
> >>
> >> Usually, I think most user partition there HD's with OS9 at the
> >> beginning, and HDBDOS *after* it.  With Boisey's Super Driver for
> >> OS9 you can partition the drive the other way around with HDBDOS
> >> drives taking the lower partition and OS9 the higher. If you format
> >> your HD this way, then you have the ability to create a bootdisk
> >> that is readable from HDBDOS (and the DOS command) solve the Bob's
> >> proposed dillema.
> >>
> >><snip>
> >>
> > Maybe you can place the Basic portion first and OS-9 last with the
> > Super Driver but that would NOT be good. Further there is no reason
> > to do that with HDBDOS.
> > 
> > RGBDOS and HDBDOS start in Disk Basic mode and read Basic disks based
> > on the offset at $D938-$D93A in the Disk ROM. If you want just Disk
> > Basic then the offset (stock I believe for HDBDOS) is $000000. The
> > default for the emulators JVC, MESS, and VCC is $5A000.
> > You can backup a 35-track single sided NitrOS-9 disk to any of 256
> > drives after the $5A000 break and boot into NitrOS-9 from that disk.
> > It just requires the correct Boot module and the program LINK.BAS to
> > correctly set LSN0 in the NitrOS-9 portion of the .vhd drive.
> > There should not be any reason why the SDC can't work this way and be
> > compatible
> > 
> > with all other Coco installations including real hard drives with
> > RGBDOS. Also, if you don't like Disk Basic, you can have HDBDOS
> > automatically boot into NitrOS-9 on startup with the use of only 1
> > or 2 Disk Basic "drives" on the hard disk.
> > 
> > With real hard drives, the offset is set by the user based on the
> > size of the drive and the desire or lack of it for OS-9 or Disk
> > Basic. The original code RGBDOS was written when drives were small;
> > not like todays monsters. :)
> > 
> > Robert
> > 
> > 
> > 
> > --
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> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco
> > 
> > 
> > 
> > --
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> > Coco at maltedmedia.com
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Cheers, Gene Heskett
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