Date   : Mon, 20 Mar 2006 22:59:11 +0000 (GMT)
From   : Steve Fewell <kranser@...>
Subject: Re: Advanced BASIC pretending to be the MOS!

> > When Advanced BASIC starts, if it cannot detect
> the
> > Tube, instead of printing a helpful 'No Tube'
> error
> > message and exiting to the MOS, it goes into an
> > endless loop of:
> > Print *
> > Input line - OSWORD 0
> > Send line to MOS - OSCLI
> > <deal with Escape condition>
> > Loop

> > Why does it pretend to be the MOS?

> OS 1.20 doesn't supply any 
> way of operating the computer without a valid
> language ROM; this way, 
> if there's some kind of problem, you can at least
> attempt to diagnose 
> the problem.

Checked, are you are absolutely correct. OS 1.20 Just
hangs instead of going into command ('*') mode. I'd
always wondered why *FX247,76 causes BBC B's to hang
on break, but Masters enter the MOS command entry
mode.

Testing with:
ROM &B = HIBASIC
ROM &C = Advanced BASIC

and no co-processor.
*FX142,12
Advanced BASIC

*
*
*
*FX142,11
HIBASIC

?_


At which point the machine hangs. Hence, Advanced
BASIC at least leaves the machine usable - even though
it gives no indication of the problem ('No Tube'!).

Steve.




       
       
               
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