From: spector@vax2.concordia.ca (Mitchell Spector)
Subject: Re: ROM 01 vs ROM 3
News-Software: VAX/VMS VNEWS 1.41    
Organization: Concordia University
Date: Tue, 12 Jan 1993 19:51:00 GMT

In article Clayten_Hamacher@mindlink.bc.ca (Clayten Hamacher) writes...

>Recently someone posted something about all the plusses of ROM 3, does it
>have any drawbacks... Not counting the fact that some badly written software
>is too ROM dependant to run on it, I'm talking about the ROM and motherboard
>itself.

	The major disadvantage is software compatibility with older programs.
As I mentioned before, quite a few have been re-written or patched to run from
a ROM 3, but a few still have not (nor will be in future). Other from that,
I can't see any more downsides, expect that the internal slots aren't labeled
with numbers on the motherboard, and the internal keyboard/numeric keypad 
connector (//e upgrade) locations are gone. Also the VGC and Ensoniq 5503 chip
are now soldered in, and can't be removed. --OH! just remebered another 
important plus the ROM 3 has that wasn't mentioned in my other post. Believe 
it or not, it's actually more compatible with 8-bit Apple IIe software than
the ROM 01 IIgs!   


>P.S. It has a newer set of tools but considering system 6 has even newer
>tools wouldn't cause those to be loaded in, thus losing the 7% speed
>advantage you gained by having them in ROM?

	This would seem to make sense, but it seems the System 5 tools in 
ROM are still used with System 6. If it's the newer tools, perhaps the
revamped motherboard design, however minor, may be the reason for the 7-8%
speed increase (Dave or Matt should be able to answer this). There *IS* a real
increase in overall speed, as I compared my ROM 01 with my ROM 3 side by side.

Using an unmodified copy of "System Disk" (System 6.0), I timed the loading
time on both machines using the same disk. It took 49 seconds for the
Finder to appear on the ROM 3, and 57 seconds to appear on the ROM 01.
I've also noticed windows scroll faster and graphics are drawn to screen
just slightly quicker on the ROM 3. 

>Also, can you tell me why programs in rom run faster than programs in ram??

	Simply because ROM reads are faster than RAM reads.

>And yet another... One version of the ROM 3 had memory peeker etc locked in..
>I would prefer this because they are in ROM and therefore not taking up any
>RAM (aside from whatever they might use when executed)..

	My ROM 3 is one of the rare versions with the CDAs locked in. To tell
you the truth, I rather I have the option of disabling them since they clutter
up my Classic Desk Accessories menu. And no, your wrong, CDAs installed from
ROM *do* take up some of your IIgs's memory. I believe it's something like
256 bytes for each CDA installed, so my system has 0.5k less available then 
every other ROM 3 machine! :-/ 

>Or do CDAs in ROM get transfered into RAM to run?

	Probably not, but for the system to have them active all the time
uses up some memory (but VERY little of course).


> 
>Clayten_Hamacher@Mindlink.bc.ca                 Land of the rising snow.

Mitchell Spector
Concordia University
spector@vax2.concordia.ca


Newsgroups: comp.sys.apple2