Questions about GS ROM1 vs. ROM3

[Jeff Ramsey]

I'm trying to learn about the differences in the IIgs versions so I can make an informed decision when I buy one.

Here are the differences that I am aware of:
1. ROM3 has a larger ROM and has System 5 tools preloaded in it, making it around 10% faster because it does not have to load the System 5 tools from disk. Can just the ROM chip be purchased and swapped?
2. ROM3 Logic Board has 1mb RAM onboard. Does the 1.5mb RAM expansion make up for the difference?

Are there other differences?

As far as expanded RAM goes:
Are there programs for the IIgs platform that require more onboard RAM or require the ROM3 version?
I see you can get 4mb or 8mb RAM cards for the IIgs. Will these work in either version?
Are there programs that will even recognize 8mb of RAM?

Sorry for the barrage of questions, but I thought it better than making 3-4 separate posts.

[David Schmidt]

On 11/7/2017 12:59 PM, Jeff Ramsey wrote:
> I'm trying to learn about the differences in the IIgs versions so I can make an informed decision when I buy one.

Why? Buy one of each. You'll be happy you did. Spares are important
in this game.

> Here are the differences that I am aware of:
> 1. ROM3 has a larger ROM and has System 5 tools preloaded in it, making it around 10% faster because it does not have to load the System 5 tools from disk.

..."ish." Some tools got patched after that and have to be loaded from
disk anyway. Apple eventually learned their lesson and quit burning
toolbox routines into ROM (on the Mac).

> Can just the ROM chip be purchased and swapped?

No. Other/different support electronics went onto the ROM03 mobo.

> 2. ROM3 Logic Board has 1mb RAM onboard. Does the 1.5mb RAM expansion make up for the difference?

As far as apps and GSOS go - yeah, pretty much. Find one of those
modern 4MB cards and you'll have all the memory any program written for
a GS needs.

> Are there other differences?

There is static/electric 'noise' that comes over the speaker in a ROM01,
and it's especially noticeable when you're running GSOS. Enough to be
bothersome, to my ear.

> As far as expanded RAM goes:
> Are there programs for the IIgs platform that require more onboard RAM or require the ROM3 version?
> I see you can get 4mb or 8mb RAM cards for the IIgs. Will these work in either version?
> Are there programs that will even recognize 8mb of RAM?

Like I said, 4MB is "good enough for anybody." I think I have run
across one inconsequential program that could use 8MB if you had it (it
played a video). Productivity apps like AppleWorks can probably use it
if you've got it. And of course RAM disks are always fun. There are
some potential issues with DMA speed IIRC (i.e. your RamFAST drive
controller may be slowed down or something) when you're dealing with 8MB
vs. 4MB.

[Jeff Ramsey]

On Tuesday, November 7, 2017 at 10:15:16 AM UTC-8, schmidtd wrote:
> Why? Buy one of each. You'll be happy you did. Spares are important
> in this game.

Thanks for the detailed response.

Would you have a specific reason to 'get one of each'? It seems to me that the ROM3 has revisions making it superior to ROM1, and the ROM1 does not have anything that ROM3 lacks.
(I reread your response and realized you mentioned 'spares' as a reason.)
What type of parts are swappable between the two versions? If ROM1 and ROM3 have "Other/different support electronics" what is swappable vs. not swappable?

I am trying to be a bit selective and not just fill up my basement with every vintage Apple that will follow me home. My collection is bit without focus or direction. It is part "One good specimen of each of my favorite Apple product lines", part "Someone threw that away, and I bet I can refurbish it and make it live again..." and part "Oooh! Shiny!!!"

[David Schmidt]

On 11/7/2017 2:14 PM, Jeff Ramsey wrote:
> On Tuesday, November 7, 2017 at 10:15:16 AM UTC-8, schmidtd wrote:
>> Why? Buy one of each. You'll be happy you did. Spares are important
>> in this game.
>
> Thanks for the detailed response.
>
> Would you have a specific reason to 'get one of each'?

Because you'll always have a reason to want/need the 'other' one if you
only get the one.

> It seems to me that the ROM3 has revisions making it superior to ROM1, and the ROM1 does not have anything that ROM3 lacks.
> (I reread your response and realized you mentioned 'spares' as a reason.)

Mmmmm. Spares good.

So the ROM01 has a little different setup with respect to slot
assignments - having to do with Appletalk. Nothing that will enable or
restrict you if you decide you want to delve into that, though. I.e.
http://www.synack.net/~bbraun/iigsboot.html

My daily driver is a ROM03. I prefer it because it's quieter with the
speaker more than anything else. I don't spend a ton of time in GSOS,
and I don't spend a ton of time playing every game out there, so it
doesn't really matter a ton. One argument for going newer is... it's
newer. Potentially longer time before the next MTBF ticks over.
(http://blog.fosketts.net/2011/07/06/defining-failure-mttr-mttf-mtbf/)

> What type of parts are swappable between the two versions? If ROM1 and ROM3 have "Other/different support electronics" what is swappable vs. not swappable?

Nothing is swappable but the power supply.

> I am trying to be a bit selective and not just fill up my basement with every vintage Apple that will follow me home. My collection is bit without focus or direction. It is part "One good specimen of each of my favorite Apple product lines", part "Someone threw that away, and I bet I can refurbish it and make it live again..." and part "Oooh! Shiny!!!"

Embrace the sprawl. Hey, wait, you have a basement?!? You have a duty,
nay, a _calling_ to fill it.

[Charlie]

On 11/7/2017 12:59 PM, Jeff Ramsey wrote:

> I'm trying to learn about the differences in the IIgs versions so I can make an informed decision when I buy one.
>
> Here are the differences that I am aware of:
> 1. ROM3 has a larger ROM and has System 5 tools preloaded in it, making it around 10% faster because it does not have to load the System 5 tools from disk. Can just the ROM chip be purchased and swapped?
> 2. ROM3 Logic Board has 1mb RAM onboard. Does the 1.5mb RAM expansion make up for the difference?
>
> Are there other differences?

The ROM 3 has the M2B0 signal wired to slots 1 through 6. The ROM 01
only has it wired to slot 3. This may seem like a minor difference but
it isn't if have or intend to get a Carte Blanche card and want to use
the VGA or DVI/HDMI video projects.
I have only a ROM 01 and had to hand wire that signal to the other slots.

Charlie

[Polymorph]

One thing not mentioned yet is that there was a *small* number of software titles written that will only run on a ROM01 due to the developers not following Apple's guidelines. However, most of these have been patched to work with the ROM03. There may still be software out there that will only run on a ROM01, but I imagine that the number of titles would be pretty insignificant.

I have both and prefer the ROM03.

Cheers,
Mike

[Bobbi]

I wonder what happened to ROM02 ??

[Mark D. Overholser]

On 07-Nov-17 12:18, Charlie wrote:
> On 11/7/2017 12:59 PM, Jeff Ramsey wrote:
>> I'm trying to learn about the differences in the IIgs versions so I
>> can make an informed decision when I buy one.
>>
>

> The ROM 3 has the M2B0 signal wired to slots 1 through 6.  The ROM 01
> only has it wired to slot 3.  This may seem like a minor difference but
> it isn't if have or intend to get a Carte Blanche card and want to use
> the VGA or DVI/HDMI video projects.
> I have only a ROM 01 and had to hand wire that signal to the other slots.
>
> Charlie
>

Which Pin is the M2B0 Connected to???

Typically Pins 19 and 35 are NC on the Apple ][s..



MarkO

[D Finnigan]

Jeff Ramsey wrote:
> I'm trying to learn about the differences in the IIgs versions so I can
> make an informed decision when I buy one.

Get a ROM 3. My first GS was a ROM 01, and as soon as I got a ROM 3, I put
the older one away and never used it again. That was almost 10 years ago.

>
> Here are the differences that I am aware of:
> 1. ROM3 has a larger ROM and has System 5 tools preloaded in it, making it
> around 10% faster because it does not have to load the System 5 tools from
> disk. Can just the ROM chip be purchased and swapped?

Maybe. The ROM 3 has an improved ADB controller and other things too that
the new ROM will address.

> 2. ROM3 Logic Board has 1mb RAM onboard. Does the 1.5mb RAM expansion make
> up for the difference?

What? Are you talking about the Apple 1MB expansion card? That will give you
2MB in your ROM 3 GS. That's what I have.

>
> Are there other differences?
>
> As far as expanded RAM goes:
> Are there programs for the IIgs platform that require more onboard RAM or
> require the ROM3 version?

Not very many, and the ones that require more RAM often need an accelerator
too. Although to be honest, the GS needs an accelerator no matter tha RAM
size.

--
]DF$
Apple II 40th Anniversary User's Guide:
http://macgui.com/newa2guide/

[John Brooks]

On Tuesday, November 7, 2017 at 3:11:23 PM UTC-8, Bobbi wrote:
> I wonder what happened to ROM02 ??

ROM2 the same as ROM3. People often called the ROM1 upgrade the 'second GS ROM'. So to 'avoid confusion', Apple called the ROM2 upgrade ROM3.

ie, Apple switched from the 0-based counting of ROM0/1 to 1-based counting for ROM3.

ROM3 is the best GS hardware version:

1) 1MB fast ram vs 256K
2) Twice as much ROM, with many toolbox & firmware improvements and bug fixes
3) Hardware shadowing of text page 2 & lores graphics page 2
4) Appletalk on modem or printer port, and without losing slot 7 card access
5) Ram disk can be resized without rebooting ProDOS/GSOS
6) Can use a card in slot 4 without losing mouse firmware
7) Battery ram can now save the enable status of Visit Monitor & Memory peeker CDA
8) New ADB controller with sticky keys & keyboard mouse
9) Boot status flag (power-on boot vs re-boot)

-JB
@JBrooksBSI

[David Empson]

Bobbi <bobbi....@gmail.com> wrote:

> I wonder what happened to ROM02 ??

When ROM 01 was released as an update to the original firmware, it had
an internal revision number of 2 but showed "ROM 01" on the splash
screen, and was sometimes referred to as "ROM 2.0" in Apple's official
documentation (e.g. see IIgs technical notes 7, 13 and 26).

This led to much confusion as to what it should be called. The name "ROM
01" stuck in common use because that is what it shows on the screen.

The original firmware had no version information on the splash screen,
and its internal revision was 0, so it was dubbed "ROM 00" after the
fact.

When the 1 MB IIgs was released, Apple used the same number for the
internal firmware revision (3) and the displayed version number "ROM 3",
so there was no ambiguity.

If Apple had released it saying "ROM 2" but with an internal revision of
3, everyone's heads would have exploded.

--
David Empson
dem...@actrix.gen.nz

[waynej...@gmail.com]

On Tuesday, November 7, 2017 at 9:59:13 AM UTC-8, Jeff Ramsey wrote:

> 2. ROM3 Logic Board has 1mb RAM onboard. Does the 1.5mb RAM expansion make up for the difference?

There were quite a few different memory expansion cards ranging from 256k to 8mb. Most of them work equally well in any IIgs. There were a few that only worked in the ROM 1. Also some that needed a chip changed to go from one version of the IIgs to the other.A number of Applied Engineering cards were that way.

[Charlie]

Pin 35 is M2B0 on the Apple IIgs except for slot 7 which is CREF (color
reference).
On the ROM 01 only slot 3 has has the M2B0 signal.
On the ROM 3 slots 1 through 6 have the M2B0 signal.
M2B0 goes low when the Mega II is addressing bank 0. Without it there
is no way (that I know of) for a video card to determine when the Super
Hires Graphics memory space is being accessed.

Charlie

[Antoine Vignau]

Another document to read: http://www.brutaldeluxe.fr/documentation/discovery/discovery_19890213_discoveryvscurrentiigs_ers.pdf

Antoine

[Brian Patrie]

On 2017-11-07 18:46, John Brooks wrote:
...

> 6) Can use a card in slot 4 without losing mouse firmware

Well, without losing the 16-bit mouse firmware. Setting slot 4 to Your
Card, on a ROM 03 will still deprive IIgs-oblivious (i.e. most 8-bit)
software of mouse access.

I do this deliberately to prevent Program Writer from using the mouse,
else dragging the pointer across the emulator window would make the
cursor fly off to Never Never Land--which irritated the crap out of me.

(Side note: Anyone know a way to properly disable the mouse in PW?)