Re: Creating Apple /// boot disks using MacADT

["Michael J. Mahon" <mjmahon@aol.com>]

jjj wrote:
> On 2008-01-19 02:17:36 -0800, "Michael J. Mahon" <mjmahon@aol.com> said:
>
> > It's easy enough to look at block 1 and be sure...
> >
> > There are lots of slips possible when Apple II tools are used
> > to capture/transmit Apple /// disks, since you can be pretty
> > sure that the images have not been verified to boot SOS since
> > originally being archived.
> >
> > -michael
>
>
> OK I looked at Block $0001 on the Apple /// System Utils disk. It was 
> just full of zeroes. However, Block $0000 is exactly the same as Block 
> $0001 of the ProDOS disk. So, I copied Block $0000 of the Apple /// disk 
> into Block $0001 of the Apple /// disk, but I still get the IO ERROR.

If block 1 is zeroes, then the disk does not have the SOS boot block.

> Then I tried this: I copied Block $0000 and $0001 exactly from the 
> ProDOS disk to the Apple /// disk. Still, IO ERROR.

If it's a faithful copy of the Apple system disk, then it should
have both the ProDOS and the SOS boot blocks.  Take a look at block
1 of your ProDOS disk to see if it's valid code.

> If I try to boot the Apple /// from the ProDOS disk, it gives a 
> different error: SOS KERNEL NOT FOUND.

That sounds right--and indicates that the SOS boot block is there.

> The weirdest thing is that in Block $0000 of the ProDOS disk, line 010 
> says the first part of my e-mail address: "JJJ.@.I" What the hell?! How 
> could my e-mail address be in there?

I think you meant "JJJJ.@.I"--that is the normal content. (!)  The four
"J"s are four LSR instructions.

> I am guessing that somehow my FTP program is messing up the disk images, 
> since why else would part of my email address be in there? Or is it just 
> the weirdest coincidence of all time? I'm just using Fetch to get these 
> DSK files from asimov.net. But why would it put part of my e-mail 
> address but not the whole thing?
>
> It's only on the ProDOS boot disk. But also I formatted a blank disk 
> with ProDOS and "JJJ.@.I" is also on that one! I'm putting my money on 
> crazy coincidence...

Bingo.

> Incidentally I noticed the Kernel file starts in Block 7 on the Apple 
> /// System Utils disk.

That's where the first file starts, so that sounds fine.

I just took a look at the SOS boot block code, and both the "I/O ERROR"
message and the "SOS KERNEL NOT FOUND" message can be printed by that
code.

So you apparently *do* have a valid SOS boot block on the ProDOS disk.
The "I/O ERROR" message is sufficiently generic that it *may* be
generated by the Apple /// ROM boot code, but I can't verify that
at the moment.

The fact that attempting to boot the ProDOS disk gets you as far as
"SOS KERNEL NOT FOUND" means that the SOS boot block has been read
and it has executed far enough to search the disk directory for the
SOS KERNEL and failed--as it should, since there isn't one on the
ProDOS disk.

This suggests that your drive can at least read the ProDOS disk
correctly, which suggests that there is a problem with your SOS
boot disk.

I know you think you copied block 1 from the ProDOS disk to the
SOS disk, but please look at block 1 of the SOS disk and verify
that it *is* the SOS boot block.  The first three bytes are a JMP
to the code's entry point at $A06E, so they are 4C 6E A0.  Then
it continues with a series of messages about SOS, so it should
be easy to recognize.

If the boot block is OK, then use any Apple II disk utility to
verify the SOS disk--to make sure that all its sectors are
readable.

If the SOS boot code is intact, and all sectors are readable,
and it still won't boot (or at least get further), then it's
likely that there is a problem with the drive.  ;-(

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

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