SE ROM In Plus

[Mac128]

Anybody tired SE ROMs in a Plus? Any reason not to try in terms of risking damage?

There is some software that will only run on an SE. My SEs are packed away or otherwise disassembled, so I thought I could just switch the ROMs and gain compatibility. I mean, how else could software determine it wasn't running on an SE?

 

[Gorgonops]

Anybody tired SE ROMs in a Plus? Any reason not to try in terms of risking damage?
There is some software that will only run on an SE. My SEs are packed away or otherwise disassembled, so I thought I could just switch the ROMs and gain compatibility. I mean, how else could software determine it wasn't running on an SE?

My vague understanding is that SE's have some significant changes to the SCSI hardware compared to the Plus, in addition to minor tweaks everywhere else. (Including significant changes to drive the keyboard on the ADB bus.) You probably won't damage the ROMs trying (assuming they're the same chips/pinout/density) but chances are you'll just get a very unhappy frowning mac in the middle of your screen.

 

[Mac128]

chances are you'll just get a very unhappy frowning mac in the middle of your screen.

Not even. No bong, just garbage on the screen.

 

[Dennis Nedry]

Cool experiment though. Now we know for sure what happens.

 

[Mac128]

Cool experiment though. Now we know for sure what happens.

Yes. It makes me wonder if there is a pin incompatibility or a software one. I should have put the Plus ROMs in the SE to see what happens. Obviously the SE ROMs were checking for hardware the Plus didn't have, but the SE should have all the hardware the Plus checks for, except for a serial mouse. Oh well something for a rainy day ....

 

[Charlieman]

I'd expect any SE/Plus ROM combination to fail. The significant differences between Plus and SE are ADB and PDS, although I imagine there are tweaks around serial and sound too.

PDS required that the SE had a Slot Manager, and Slot Manager is found in ROM code for all Macs based on "NuBus architecture". A Mac doesn't need to have NuBus slots to use NuBus architecture; the latter was employed in PowerBooks and the LC family. In the SE, Slot Manager is going to juggle all of the memory addressing and introduce new hardware interrupts, so it is unlikely to work with earlier models.

Think about the two Mac Portables: they demonstrated that a 68000 Mac could have a useful amount of RAM and you could even hook up to an expansion chassis with SE PDS cards, but the ROMs introduced new hardware compatibilities for those cards.

 

[porter]

except for a serial mouse.

I've never known a Macintosh with a "serial mouse". Where does this mythical beast fit it to the picture?

 

[Mac128]

except for a serial mouse.

I've never known a Macintosh with a "serial mouse". Where does this mythical beast fit it to the picture?

Way to beat a dead horse. For anyone actually confused by my statement, let me re-phrase: "DE-9 Mouse". Hope that clears things up.

 

[trag]

The Outbound Laptop Model 125 could use either the Plus ROM or the SE ROM. I think that all of mine use the Plus ROM. It would be interesting to see one which uses the SE ROM to see how Outbound handled the difference.

Of course, Outbound had their own I/O scheme so it could be that the Model 125 just ignored the I/O code, be it Plus or SE, and used its own. The Model 125 has two EEPROMs onboard which provide compatibility boot code and such things as the (IDE) hard drive parameters and such.

 

[yuhong]

PDS required that the SE had a Slot Manager

I don't think so. Slot Manager was for 68020 and later Macs, I think, not for 68000 Macs, whether they had a PDS or not.