🚀 go-pugleaf

>  CAN A 520/1040 BE UPGRADED TO 4 MEGS OF RAM ??
>  
>  I know the MMU can handle it, but what about the rest of the system ?
>  (ROMs, power supply, wiring,...).
>  
>  I would be thankful if somebody from Atari could provide a straight
>  answer to this question (Neil, Allan, Landon,...?). I'm sure this is
>  of general interest.  And it'll save me the trouble of stripping down
>  my 1040 to figure it out by myself !


Well ... theoretically.  We have one in the lab (a prototype 4
megabyte 1040) but for all its logical and inherent beauty, it is
really a wire-wrap mess.  It will never fit back into the plastic
case.  Thanks to lots of copper braid (for power and ground
distribution) the DRAMs are solid and reliable, but nothing beats
a good DRAM layout.  Wire-wrap isn't.

And naturally, Atari doesn't condone that kind of upgrade.

There is a further problem, though.  Our old friend GEMDOS
insists on zeroing the TPA as part of doing a Pexec().  The
original code (also in the current ROMs) is written in C and it
is rather slow.  On the 1040 this is evidenced when the machine
"takes a breath" just before starting an application.

A four megabyte machine bloody well holds its breath until it
turns blue -- it takes eight to ten seconds to zero the TPA.
Needless to say this has been fixed -- it is now blindingly fast
-- but you really need new ROMs for anything over a megabyte.
The "Mega" STs will have these ROMs.  I do not know if they will
be made available for other machines.

-- 
-Landon Dyer, Atari Corp.	    {sun,lll-lcc,imagen}!atari!dyer

The views expressed here do not not
necessarily reflect those of Atari Corp.	Segments are for worms.