[Coco] CocoSDC booting OS9

[Gene Heskett]

On Tuesday 18 November 2014 11:04:36 Brett Gordon did opine
And Gene did reply:
> Gene: excellent! .. I see where the superblock only has a 2 byte value
> for the size in *bytes* of the allocation map... my mind translated
> that to a 16 bit number of *sectors*  Whoops!   Then your calculation
> was correct.  This also mean that having a boot-track could NOT
> conflict with the allocation bitmap.  ME a Dummy!
> 
> This means that Bob's original concern over the boot track getting in
> the way of RBF sector allocation is unfounded?
> 
OS9Gen or presumably cobbler too, use track 34 and allocate it in the map, 
nicely and silently ignoring the previous usage of track 34.

> On Tue, Nov 18, 2014 at 10:02 AM, Gene Heskett <gheskett at wdtv.com> 
wrote:
> > On Tuesday 18 November 2014 07:43:20 Brett Gordon did opine
> > 
> > And Gene did reply:
> >> As of now, HDBDOS only support the standard FDC emulation of SDC. 
> >> The LBA mode of SDC isn't support by HDBDOS, until someone writes a
> >> driver for it. I might take up that project of the toolshed people
> >> see fit, as it will benefit the community plus help my cocoboot
> >> project (which borrows the HDBDOS drivers for its harddrive/DW)
> >> 
> >> 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.
> >> 
> >> To answer Bob's original question:
> >> 
> >> At clusters of 1 sector (the defacto standard?), a Combined OS9 RBF
> >> with a boottrack can be:
> >> 
> >> 630 sectors - 18 boottrack - 1 superblock = 611 sector for
> >> allocation bitmap X 256 bytes per sector = 156,416  bytes for
> >> allocation bitmap X 8 bits per byte = 1,251,328 bits in allocation
> >> bitmap
> >> X 256 bytes per sector = 320 Megs
> >> 
> >> -Brett
> > 
> > Sorry Brett, but the allocation map is hard limited to 65536 bytes.
> > We expand for up to 4.2Gb by making one bit in the map correspond to
> > more than one sector on the media.  The 4.2Gb limit is reach when we
> > are out of LBA addresses with only 24 bit sector addressing.
> > 
> > So above, the one sector per cluster bit maximum is just a hair over
> > 131 megabytes.
> > 
> >> On Nov 17, 2014 10:20 PM, "Robert Gault" <robert.gault at att.net> 
wrote:
> >> > Brett Gordon wrote:
> >> >> That sounds like a fine idea!  It's just a matter of changing OS9
> >> >> and BASIC to agree to do something different.
> >> > 
> >> > I don't have the SDC and don't know how it is supposed to work. If
> >> > it supports HDBDOS and can accept a .vhd such as is used by a
> >> > real Coco, the JCV, MESS, and VCC emulators, then it is trivial
> >> > to place a 35-track single sided "disk" in the Disk Basic portion
> >> > of the .vhd. That is your OS-9 boot disk and there is no need to
> >> > worry that OS-9 and Basic use different directory structures.
> >> > 
> >> > You can also set up the boot disk for automatic booting at turn
> >> > on, if you only use OS-9.
> >> > 
> >> > Robert
> >> > 
> >> > 
> >> > 
> >> > --
> >> > Coco mailing list
> >> > Coco at maltedmedia.com
> >> > https://pairlist5.pair.net/mailman/listinfo/coco
> > 
> > Cheers, Gene Heskett
> > --
> > 
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > 
> > -Ed Howdershelt (Author)
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
> > US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS
> > 
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS