Re: Debugging an (unsuccessful) prodos boot

[Scott Hemphill <hemphill@hemphills.net>]

BLuRry <brendan.robert@gmail.com> writes:

>>
>> So, you are debugging your emulation then?  Then there are a couple of
>> things you might want to fix: the "e5" at byte 5 should be "f5" to
>> indicate that it's the volume directory.  Also the block counts for the
>> files should be fixed.  Right now they're all 1s.
>>
>
> Yeah, I had Fx originally for volume directory, but it looked like the
> prodos MLI call was checking against an E0 mask.  I'll try putting it
> back as I've gotten one step further.  About the block counts, and why
> they show as one:
>
> When file structures are populated (mind you, only done on-demand),
> only the base blocks are allocated.  Because of the way I wrote the
> block count (counts number allocated rather than proper logical
> number), it reports only 1 for things that have not been allocated
> because they've not been actually requested yet.  I should be able to
> fix this rather generically, but that will be once I get over the next
> big hurdle.
>
> So problem was actually that the volume name started with a period
> character -- stripped that out and now...
>
> ... IT STARTS ASKING FOR BASIC.SYSTEM.  Now to finish implementing
> file reads -- which are loads easier than directories.  Thanks for
> your help guys!  Hopefully we'll all have a fun toy to play with
> shortly.

Congratulations!  I'm glad things are working.  A couple of more things
about your emulation: you've set all the bits in the access codes, but
one of them is the invisibility bit.  I'm guessing you get no files in a
directory catalog.  The other thing is: does putting a file in block 0
work?  A zero pointer is used in the index block to indicate that no
block is allocated.  So I could imagine that ProDOS could do something
weird if it sees a zero file pointer in a directory entry, like return a
buffer of zero bytes on a read.

Scott
-- 
Scott Hemphill	hemphill@alumni.caltech.edu
"This isn't flying.  This is falling, with style."  -- Buzz Lightyear