Re: New idea HD for C= and 1541 ROM Listing

From: Richard Atkinson (
Date: 1999-09-06 18:08:51

On Sun, 5 Sep 1999, Frank Kontros wrote:

> > Connecting an IDE-drive to a 1541
> >       The idea is to addapt the above interface so it can be used by the 6502
> >       in an 1541-drive. Then you have to change the Kernal. Problems: 1)
> >       there is no listing INCLUDING comments etc. available.
> I'm just working on it. The half o'work is done. I plan also collect the
> sources
> on funet and make also another better listing with cross-ref. table.

What interfacing hardware are you using? I propose that IDE be mapped into
the 6502's address space below the VIAs, with CS0 at $1000-$13FF and CS1
at $1400-$17FF. This uses spare outputs on the address decoder.

For a filesystem, why not use regular 1541 DOS 2.6 but add an extra
filetype (DIR or so) as an entry in the BAM which points to another
'virtual 1541 disk' on the hard drive. This way each directory is limited
to 664 blocks and 144 entries (or whatever the fundamental limits are) but
you can have a directory structure of unlimited depth. Does anyone know
how filetypes (PRG, USR, SEQ and REL) are implemented?


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