Re: Support for 4KB sectors size disk ?

[Tom Ivar Helbekkmo <tih%hamartun.priv.no@localhost>]

David Brownlee <abs%netbsd.org@localhost> writes:

> (Irrelevant historical sidetrack)
>
> I thought at one point it was common for BSD derived systems to be
> able to support arbitrary block sizes? Certainly I remember using
> 42nix (BSD 4.2+clutter on NS32016) and being able to format the MFM
> drives with differing block sizes.

It's certainly not there in NetBSD now, anyway.  I had a lot of fun
rewriting the floppy driver and some surrounding code to allow me to do
this in /etc/floppytab (note varying sector sizes, and choice between FM
and MFM encoding):

stride|5.25 inch 640KB Stride floppy in 1.2MB AT drive:\
        :nbps#512:\
        :ncyl#80:\
        :nspt#8:\
        :ntrk#2:\
        :stepspercyl#1:\
        :gap1#88:\
        :gap2#165:\
        :fillbyte#229:\
        :xfer_rate#307200:\
        :mfm#64:\
        :interleave#1:

osborne-sd|5.25 inch 100KB Osborne 1 SD floppy in 1.2MB AT drive:\
        :nbps#256:\
        :ncyl#40:\
        :nspt#10:\
        :ntrk#1:\
        :stepspercyl#2:\
        :gap1#7:\
        :gap2#13:\
        :fillbyte#229:\
        :xfer_rate#307200:\
        :mfm#0:\
        :interleave#1:


osborne-dd|5.25 inch 100KB Osborne 1 DD floppy in 1.2MB AT drive:\
        :nbps#1024:\
        :ncyl#40:\
        :nspt#5:\
        :ntrk#1:\
        :stepspercyl#2:\
        :gap1#51:\
        :gap2#95:\
        :fillbyte#229:\
        :xfer_rate#307200:\
        :mfm#64:\
        :interleave#1:

-tih
-- 
Self documenting code isn't. User application constraints don't. --Ed Prochak