Re: apple II ROMS: what rom will go to next slot if there is no 5.25 in drive?

[david@uow.edu.au (David E A Wilson)]

at217@chebucto.ns.ca (Michael Hackett) writes:

>itsme (quantum@telis.org) wrote:
>> What kind of modifications do I have to do to the DISK II controller to 
>> add "giving up" feature?

>This is a bit out of my field, but would not just adding a timeout to
>the read code in the firmware, and a suitable handling in the boot
>code, allow it to pass control on up the slots? (Sorry if I'm stating
>the obvious. :-) )

This is what was done to the code in the Apple //c (ROM Rev 0,3,4). The
only problem with retrofitting this code change to the Disk ][ controller
is that the ROM is only 256 bytes in size and as far as I know is full....

Thus the Disk ][ must be the last drive in your system which causes a problem
if you want more than one other disk controller (as only slot 7 is checked
before slot 6 which is the default for 99%+ of all Disk ][ controllers).

Either move the Disk ][ to say slot 4 (then you can boot from 7,6 or 5 before
the Disk ][) or as I did in one of my //e computers, change the boot scan to
go 1..7 rather than 7..1.
--
David Wilson	Dept CompSci Uni Wollongong Australia	david@cs.uow.edu.au