Re: Any way to make a "dual boot" apple II disk?

[Andy McFadden <fadden@fadden.com>]

Jeff Lodoen <jmlodoen@thegrid.net> wrote:
>>    With out trying to find 'Extra K' how did it really work?
>> 
>>          -Lockar
> 
> TECHNICAL NOTES
> ---------------
> HYBRID.CREATE puts an empty ProDOS catalog on track 0 and tells ProDOS that 
> only tracks 0 through 16 are available. It then puts an empty DOS 3.3 
> catalog on track 17 and tell DOS 3.3 that only track 17 through 34 are 
> available. The result is that each DOS gets approximately half of the disk. 
> Both DOS's are happy with this set-up because ProDOS expects its directory 
> to be on track 0, while DOS 3.3 looks on track 17.


This does not actually create a "dual boot" disk.  The disk always boots
into ProDOS.  To get at the DOS 3.3 section, you have to boot a DOS disk
first, which kind of defeats the purpose of having them all on one disk.

If you have a 3.5" drive, you can use Glen Bredon's DOS MASTER to create
a 140K DOS volume on a ProDOS disk.  You then "boot" DOS from within
ProDOS.  You may also be able to use one of the "DOS 3.3 launcher" utilities
in this manner.

A note to CiderPress owners: you can get at either part of a "hybrid"
disk by enabling "Confirm disk image format" in Edit->Preferences->
Disk Images.  CP finds the DOS 3.3 image first, but if you change the
"Filesystem format" selection to ProDOS, it will let you access the
DOUBLE.DOS.DISK area instead.  In an ideal world it would handle these
like any other mixed-format disk and show all files simultaneously, but
hybrid disks were so rarely used that it didn't seem worth the effort.

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