Date   : Thu, 04 Jan 2001 11:41:47 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: INKEY function

Thomas Harte <t.harte@...> wrote:
> Not a lot to add, but according to the Electron AUG at least, page 46
> [snip] returns information about OS type, not information about hardware
> type. Of course the two are strongly linked, but I'm just trying to help
> a little.
 
I wasn't refering to the hardware type, but the "host".  Osbyte 0,<>0
returns the host value.  Osbyte 129,-256 (INKEY-256) - as described on p46
above - returns the host varient.  It is important not to confuse the
different sets of values Osbyte 0 and Osbyte 129 return.  Importantly,
some systems do not have INKEY-x or Osbyte 129 available.  From the host
you can infer certain things about the hardware, but the whole Acorn
philosophy is to abstract the hardware away so that the application and
user don't need to know what the hardware actually is.
 
The operating system version number of a BBC host system forms a subset of
the full set of hosts, ie hosts 1 to 5 correspond to BBC hosts with
operating systems 1.xx to 5.xx.  Host value 6 does not correspond to
anything with OS 6.xx.  It corresponds to Arthur 0.xx, 1.xx, RISC-OS 2.xx,
3.xx, 4.xx, etc.
 
> Also, a return of '0' apparently means 'BBC OS 0.1', although I don't
> suppose you'd ever see that.
 
BBC OS 0.xx always returned an error to Osbyte 0 regardless of the
parameters passed.  The Electron returns 0.
 
-- 
J.G.Harston (JGH BBC PD Library) 70 Camm Street, Walkley, SHEFFIELD S6 3TR
jgh@...                - Running on BBCs & Masters with SJ MDFS FileServer
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