[Coco] CocoSDC disk format

[Gene Heskett]

On Sunday 30 November 2014 15:28:47 Bob Devries did opine
And Gene did reply:
> On 1/12/2014 12:34 AM, Gene Heskett wrote:
> > If you do make an os9 boot disk using the defaults, I have no clue
> > where it would put the boottrack since its being treated as a hard
> > drive. In that event, what is the stp doing? Something like our /sh
> > does?  Which if set correctly is used as the index into which vdisk
> > hdbdos would access.
> 
> 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.
> 
> > Does it still put the boottrack starting at sector 612 decimal? ded
> > can answer that.
> 
> Yes.

That might be the problem because that is likely NOT the LSN address that 
is in the $D939-3A-3B (I think thats the right address but dbl-check the 
hdbdos docs on that, and write an rsbasic script that pokes those 
addresses with $00, $02,$64 and see if it at least tries to boot.

Also, take ded to that disk and check to see if the sector address for 
os9boot and its size are properly stored in  DD.BT and DD.Bsz.

Gotta be a disconnect there someplace Bob.
> 
> > I think we have a learning event here folks.  Perhaps format it in
> > 500 megabyte chunks for nitros9, then a whole series of "hdbdos"
> > partitions? Generating a whole series of sdch, sdci etc partitions,
> > each of which could have the proper wpc amd ofs settings and using
> > the individual vdisks by setting the stp value as we do now? 
> > Interesting possibilities here. Like taking the drv number back to
> > zero in sdc1, and setting the offsets to start at the end of drive
> > 0. Using the defaults I see above, that would put a wpc=3 and an
> > ofs=F800 based on the sdc0 settings giving 0x3F800 sectors, or
> > 66,584,576 bytes for "partition 0".  That could be expanded but not
> > quite to 2 times, as beyond 131 megabytes the cluster size has to
> > increment in powers of two because the FAT table can only be 65535
> > bytes maximum.
> > 
> > I need to get mine plugged in and play, but I've spent more than my
> > share of time in the basement already this week, trying to make a
> > good level 3 boot floppy, using broken tools, I have found that
> > os9gen will not replace the boottrack, so I am trying to add a -f
> > force option to it. Unsuccessfully so far.
> > 
> > But I have an 25th anniversary coming up Tuesday that I have to act
> > like I'm interested in.  Unforch, at my age & diabetic condition,
> > and her COPD condition, its likely to be just a date on the
> > calendar. :(
> > 
> > The highlight of the day will probably be dinner at the local steak
> > house buffet. But early enough we get back in time for Wheel &
> > Jeapardy, can't miss those.  :)
> > 
> >   Also trying to get my milling machine setup with good enough jigs
> >   on the
> > 
> > table to make the huge box joint fingers it takes to do Green & Green
> > joinery. I've already rounded up some Gabon Ebony, solid black for
> > the trim bits, and enough Mahogany for the ends of the chest, but
> > I'll have to have about 25 bd/ft of it shipped in for the sides,
> > bottom & lid because no one stocks any Mahogany locally.  And I'm
> > going one step farther by lining it with aromatic cedar.  Thats the
> > plan at this point anyway.
> > 
> > Its on the cover, and is a feature article in this months Fine
> > WoodWorking magazine if anybody wants to see it.
> > 
> >> Now, there no problem with this in normal usage, but when I try to
> >> create a new OS9Boot file, and specifically a new boot track, it
> >> fails miserably; I cannot boot from the resultant disk image.
> >> 
> >> Is there a technical reason for this apparent discrepancy? If not,
> >> can the descriptor and the format command in the build be made the
> >> same?
> > 
> > Format, unless told not to by a bit in the descriptor, will query the
> > device for its capacity and will arbitrarily calculate all that so as
> > to use the whole device, see the docs for superdesc about that.
> > You'd want to set that bit in the descriptor with dmode that makes
> > format use the descriptor values instead. Fixing that is makefile
> > twiddling so its done by default.
> > 
> > And once you have done that, SAVE those descriptors with a unique
> > name and modify your bootlist to use those rather than the repo's
> > versions. When doing custom devices, its best to have continuity
> > when making a new boot disk.
> > 
> >> Regards, Bob Devries
> >> Dalby, QLD, Australia
> > 
> > Cheers, Gene Heskett
> 
> Regards, Bob Devries
> Dalby, QLD, Australia


Cheers, Gene Heskett
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