Re: ROM 3 Questions

["william strutts" <wrstrutts1@home.com>]

"David Empson" <dempson@actrix.gen.nz> wrote in message
1evzxdp.nrjk3fwb8hxcN%dempson@actrix.gen.nz">news:1evzxdp.nrjk3fwb8hxcN%dempson@actrix.gen.nz...
> william strutts <wrstrutts1@home.com> wrote:

> > The Control Panel Screen shows Control Panel, Alternate Screen
> > Mode, Visit Monitor and Memory Peeker.
>
> The Visit Monitor and Memory Peeker CDAs are available on all ROM 1 and
> ROM 3 machines, but they aren't supposed to be visible until you go into
> the monitor and use the # command.
>
> There is a minor bug in the ROM 3 firmware which means that it doesn't
> initialize the memory location which determines whether or not these
> CDAs are enabled.  When you power on the computer, the vast majority of
> machines happen to start up with this location set to zero, so these
> CDAs do not appear until you use the # command.
>
> For a very small number of ROM 3 machines, this location happens to
> contain a different value when powered on (probably FF), so these CDAs
> appear at startup.
>
> This behaviour is an artifact of dynamic RAM - it tends to power up with
> a particular pattern of values, and this will be reasonably consistent
> for the same memory chip.
>
> I know that Mitchell Spector's ROM 3 has this particular behavioural
> glitch.  I only recall ever hearing about one other machine which does
> it.
>
I located another ROM 3 yesterday which I bought for the cards
and it has the same menu items available.

--
--
William R. Strutts - wrstrutts1@home.com - Whatever!

C'est moi!  http://www.facelink.com/wrstrutts

Just hacking away...