Date   : Sun, 29 Nov 2009 21:36:36 +0000
From   : kevin@... (Kevin Bracey)
Subject: Tube - I/O processor memory questions

Sprow wrote:
> You may wish to study
>   http://www.mdfs.net/Software/Tube/BBC/Host100.lst
> for the host side.
>   
Ta for that reference. That basically answers the question - pretty much 
all of 00.8F and 400..7FF are being used. I'll treat them as out of 
bounds. I thought I'd seen some suggestion that 600..7FF were free, but 
clearly not.
> You don't need to bother. If it's a 6502 parasite just formulate the block
> in its zero page and call OSArgs: it collects up the parameters, shoves them
> down the Tube, whose host code places them graciously in the host for the
> filing system to operate on. The host then collects up the result and posts
> it back down the Tube which places it back in the parasite for you as though
> nothing special had happened.
>   
Phew. Wrong information in the (New and original) Advanced User Guides 
there. Seemed a bit whacked out. App Note 004 confirms that the data is 
transferred as part of Tube protocols, just like any other OS call.

Kevin