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Re: CFFA and MicroDrive partitions

mojoehand wrote:

On May 28, 9:31 am, "Bill Garber" <willy4...@garberstreet.com> wrote:

"schmidtd" <schmi...@my-deja.com> wrote in message4206feb3-2577-44c2-88b4-f84d575b45ce@b21g2000vbh.googlegroups.com">news:4206feb3-2577-44c2-88b4-f84d575b45ce@b21g2000vbh.googlegroups.com...

On May 27, 5:06 pm, mojoehand <mojoeh...@gmail.com> wrote:


While using CiderPress to copy a volume made on a CFFA to a CF card
destined for a MicroDrive, I got an error. The CFFA volume was 65536
blocks and the MicroDrive volume is 65535 blocks. One block smaller,
so I couldn't copy the volume.
Is there a reason for this? Which is the correct size?

The max volume size for ProDOS is 0xffff blocks, so 65535 is correct.

May I suggest that ProDOS volume size 'is' 65536, because zero is a block.
So, therefore, it would be $0000-$FFFF or $10000 or 65536. The partition
Editor in the Microdrive warns you when you get to 65536 or $10000 by the
"!!" after where it shows you the size you are making that partition. It's
not an oversize warning, it is a MAX size warning. I make them that size
all the time, and I never have a problem writing a CFFA partition over to
a Microdrive partition.

Bill


I'm just following the instructions in the Microdrive manual for
assigning the maximum volume size. This gives me a partition that is
65535 blocks. Whether ProDOS is counting from zero or one for blocks,
I don't know.


The manual is incorrect.

ProDOS supports volumes with up to 65536 blocks, with a maximum block
number of 65535.  All block numbering begins with zero.  Zero never
occurs as a ProDOS file system block pointer, because blocks 0 and 1
are reserved for boot blocks.  Therefore, the zero block pointer is used
as the null block pointer.

-michael

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