Re: FD-2000 and CMD Native Partition Info

From: eyethian (
Date: 2001-11-20 07:39:41

I wrote earlier:
> After some preliminary disassembly of FD-TOOLS program, I ascertained that
> the default partition number is located at offset $e2 & $e3 located in the
> Hardware Block of the system partition of a FD-2000 formatted diskette. It
> is not a word value, but a value representing the default partition is
> stored twice. For example, if partition #2 was set the default partition,
> offset $e2 and $e3 would contain a value of 2 each. Anyway, I will confirm
> this when I do make some test FD-2000 disks and use 1581COPY to load them
> into my PC and use HIEW.
Nick Coplin responded:
> Have you had a chance to confirm this? All the images I checked over the
> weekend had "01" in these locations....
Yes, it is confirmed. Many people do not bother changing the default
partition on a FD-2000 disk. I have sent you a TEST.ZIP file in a seperate

TEST4.D2M contains a FD-2000 disk image with eight 1541 partitions and
partition #4 is the default partition. A value of 4 and 4 was found at
offset $e2 and $e3. TEST8.D2M contains the same exact FD-2000 disk image as
TEST4, but this time, with partition #8 as the default partition. A value of
8 and 8 was found at offset $e2 and $e3.

More interestingly, I sent you the TEST.D2M file. It is the same FD-2000
disk image, but I deleted the eight 1541 partitions and replaced it with a
single native partition, partition #1, with 6400 blocks in size, named it
GODOT, and the default partition is #1. I examined this disk image under
HIEW and I found all eight 'ghost' 1541 disk headers. Additionally, in the
system partition, partition #1 is replaced by the GODOT diskname and
partitions #2 through #8 retained their original 1541 disknames, of which
now such partitions now no longer exist. So, the FD-2000 actually does a
short format in this instance and does not even bother to remove the
partition name entries from the system partition if they are deleted.

-Todd Elliott

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