Lots of bits low, so yes.

See #00 comment above :-)

Yep.

And by the 128Kb paging scheme (as in #7FFD, etc).

#E0 is even. #E1 again has lots of bits low and will probably trigger
various things (eg Interface I, which is on bits 3 and 4).

I think you need to start thinking in terms of bit fields, rather than
simple numbers. The problem here, is that all the low 8 bits are taken
by something (ULA, 128Kb/Sinclair joysticks, disk interfaces,
Interface 1 x 2, Kempston x 3). To work out what's free, we're going
to have to find out the decoding schemes used by all these
interfaces...

OTOH, if we're not going to be writing large amounts of data to this
port, we could consider using one of the upper 8 bits of the bus, as
the extra set up time wouldn't then be important.

If we do want to use a port under #100, we may have to go for an Ugly
Hack solution of making it use either bit 2 or 3, and just say
`Sorry. You can't use this if you've got both a disk interface and an
If1 attached' -- what compatability problems are there between the
various disk interfaces and the If1 at present? For example, can you
use an MB02 with the If1?

Phil

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