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From: stank@anvil.WV.TEK.COM (Stan Kalinowski)
Newsgroups: comp.sys.atari.st
Subject: Re: Mega with TOS 1.4 crashes!
Message-ID: <5286@orca.WV.TEK.COM>
Date: 9 Nov 89 22:58:29 GMT
References: <5440075@hplsla.HP.COM> <1989Nov8.173612.8571@mentor.com>
Sender: nobody@orca.WV.TEK.COM
Reply-To: stank@anvil.WV.TEK.COM (Stan Kalinowski)
Organization: Tektronix, Inc., Wilsonville, OR
Lines: 37

In article <1989Nov8.173612.8571@mentor.com> dclemans@mentor.com (Dave Clemans @ APD x1292) writes:
	.
	.
	.
>One problem can come up if you switched from a two chip to a six chip
>ROM set.  The ST runs right at (or above...) the upper margins of the
>drive capability of some of the buffer chips.  If you happened to have
>weak buffer chips (particularly the two 74ls373 chips) or a weak
>memory controller chip (the MMU; chips stamped with "imp" especially

As a proud new owner of the TOS 1.4 ROM set, I'm a little apprehensive
about installing them given all this talk about weak drivers and such.
(I'm also lazy.)  I hit upon the idea of copying the TOS roms into a
PROM programmer and making a higher density, 2-ROM chip from the 6-ROM
set that I bought.  It seems like it should be fairly straignt
forward.  I should be OK from a copyright/legal standpoint as long as
I continue to hang on to my original 6 ROM set.  (I believe this would
be equivalent to making a backup copy.)  What I need to know is what
is the common device number used for the 6-ROM set, what is the common
device number for the 2-ROM set, and is there a pin compatible EPROM
version of the 2-ROM device number.  I could try to stare at the PC
board and figure it out myself, or better, try to find a schematic,
but I though I'd ask here because I suspect some people may know
off-hand. 

							stank

PS: It just occurred to me that this whole plan could backfire if the
total amount of code stored in the 6-ROM set is larger than the size
of the higher density ROMs, perhaps this is why nobody has discussed
this idea here.  If this is the case, it will become obvious to me
once I know what the part numbers are.  For now, I presume Atari went
with the lower density parts because they were cheaper.
US Mail: Stan Kalinowski, Tektronix, Inc., Interactive Technologies Division
         PO Box 1000, MS 61-028, Wilsonville OR 97070   Phone:(503)-685-2458
e-mail:  {ucbvax,decvax,allegra,uw-beaver}!tektronix!orca!stank
    or   stank@orca.WV.TEK.COM