Re: 1541IDE and 1541IDE-S -- and 8250IDE? (and 64IDE, now)

From: Jim Brain (
Date: 2007-12-24 21:51:14

David Wood wrote:
> I'm not attempting to be a featurist, but I see no reason why we shouldnt
> use a more real FAT filesystem.  Compatibility is always a goal, but if we
> change the filesystem even in the slightest bit, we lose compatibility with
> programs that directly read and write sectors.
I think, in today's environment, one should have many choices.  I 
believe Ruud's goal is this as well.  I vote for it.

As such, FAT should be high on the list.  It's a brain-dead format, so 
it should be easy to implement (what am I saying, it IS easy, even I did 
it).  A FAT-variant that is more CBM-like is also a possibility.

The SW principals on this project should quickly come up with a module 
approach for FS code.

Then, one should use IDE partition tables to denote the partitions, 
using 0xf8 (unused, as far as I can tell) as the notation for CBM-FS.  
Then, using the Linux/*BSD superblock approach, put the specific variant 
in the superblock, along with other interesting information (name, 
etc.).  Use a major/minor approach, and allow the superblock to grow (if 
Linux/*BSD allow that , if not, don't bother)

FS-types should include:

1541/1551,2031,2040/3040/4040, using the same major # and minor numbers 
to denote variants
8050,8250,SFD, same here, only worry about per disk stuff, not per dual 
drive (you cna handle dual drive semantics in DOS)
CMD-HD Native
CMD-HD Foreign
D90XX  (sure, the likelihood it will be implemented is small, but let 
someone with an itch to scratch have the ID, use the lower byte for the 
variants (9060/9090)
IDE64 (assuming it needs a special major number, or does not already 
have one)

I think A major number should be devoted to experimental FS, like DebFS 
and the like.  Then, if they grow into something useful, move them int 
their own major.

A little thought in the beginning (module approach, superblocks, 
partitions, major/minors for FS types) I think will allow everyone to do 
as they wish.


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