jjj <jjj.@.i.o.com> 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.
OK I looked at Block $0001 on the Apple /// System Utils disk. It was
just full of zeroes.
That's not going to boot an Apple ///.
However, Block $0000 is exactly the same as Block $0001 of the ProDOS
disk.
Was that a type? I'd expect block 0 of a SOS disk to be the same as
block 0 of a ProDOS disk.
SOS doesn't use block 0 and ProDOS doesn't use block 1.
A "dual boot" disk will have the ProDOS boot code in block 0, and the
SOS boot code in block 1.
A ProDOS-only boot disk will have ProDOS boot code in block 0 and
probably zeros in block 1.
A SOS-only boot disk will have SOS boot code in block 1 and probably
zeros in block 0.
A disk which isn't set up to boot either OS (formatted and has a
directory, but no boot blocks) could have arbitrary junk in both blocks
0 and 1.
So, I copied Block $0000 of the Apple /// disk into Block $0001 of the
Apple /// disk, but I still get the IO ERROR.
Then I tried this: I copied Block $0000 and $0001 exactly from the
ProDOS disk to the Apple /// disk. Still, IO ERROR.
If I try to boot the Apple /// from the ProDOS disk, it gives a
different error: SOS KERNEL NOT FOUND.
This implies that ProDOS disk contains the Apple /// boot code in block
1. It attempts to load a file called SOS.KERNEL (or something like
that).
Not sure what is going on with the I/O ERROR messages, but that usually
means the disk is unreadable, or it tried to access a nonexistent block
(block number out of range).
Perhaps there is a problem at a later point on the Apple /// disk.
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?
What do you mean by "line 010"? What address offset? What are the actual
byte values at that point? (ASCII is ambiguous - might have the high bit
set or clear.)
I don't have a working Apple II system on hand to check if that is
normal.
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...
Incidentally I noticed the Kernel file starts in Block 7 on the Apple
/// System Utils disk.
That's arbitrary.
The directory is blocks 2-5, and the volume bit map is block 6. The
first file saved on the disk will normally start at block 7 but it just
happens to be the SOS Kernel.