Re: And the trace begins... Pick-A-Dilly Pair

[Hot Rod <hotrod.apple2@gmail.com>]

On Thursday, October 25, 2012 1:43:16 PM UTC-5, Steve Nickolas wrote:
> On Thu, 25 Oct 2012, Hot Rod wrote:
> 
> 
> 
> > On Thursday, October 25, 2012 12:18:06 PM UTC-5, Steve Nickolas wrote:
> 
> >
> 
> > First batch:
> 
> > $13 $0E; $02D0; #$1
> 
> > $14 $0E; $0F01; #$11
> 
> > $16 $0E; $5FFC; #$0E
> 
> > $17 $0E; $8FFC; #$06
> 
> > $18 $0E; $6FFC; #$20
> 
> >
> 
> > then there's a #$00 at $E6A signaling the end
> 
> >
> 
> > Second batch:
> 
> > $1B $0E; $3FFC; #$09
> 
> > $1C $0E; $4EFC; #$0E
> 
> > $1D $0E; $60FC; #$2F
> 
> >
> 
> > then another #$00 at $E7A to signal the end
> 
> >
> 
> > The sectors are read in descending order; the tracks are read in ascending order.
> 
> > The buffer addresses are starting addresses, and are incremented (hi byte).
> 
> >
> 
> > Since the starting address mostly start at the $xxFC offset, that suggests to me that these are probably binary DOS files, and the normal four-byte header is loaded into $xxFC so that the real data is able to then land starting at the next page boundary.
> 
> >
> 
> > ]HR
> 
> >
> 
> 
> 
> Ah.  The 0 was screwing me up!
> 
> 
> 
> -uso.

FWIW, these do all correspond to the D.1 through D.8 files on the disk. So this routine is just loading them directly via RWTS instead of doing BLOADs via DOS. The load address is set to start four bytes before the actual file, to absorb the address and length bytes at the start of the them.

So I suspect that the 'copy whole disk only' guidance is there to ensure that these files stay in their exact places on disk; if that's the case, then there may not be any other data on the disk (but that's unconfirmed).