Can this be done? PPC upgrade on 6100?

[wilykat]

First up, I was reading about DOS card for the 6100 and how it could also be used in Quadra because without the 6100 angled adapter, it uses Quadra style PDS slot. The adapter however won't fit either the 610 because the slot is different.

The PPC upgrade I have for Quadra also uses PDS style slot, and also works in all Quadras.  So I was wondering what would happen if I used the angled adapter intended for DOS card and plugged the PPC upgrade card then used that in the 6100?  Supposedly the upgrade card runs at double speed the stock CPU so the upgrade could be doing 120MHz or 132MHz?  

 

[Elfen]

Technically, in theory, Itso Facto... It should work.

Other PPC Upgrades do work for the 6100, I don't see why not this one too.

 

[olePigeon]

I'd be worried about them being electrically incompatible and something blowing up.

 

[Elfen]

Then the question is or should be - is the PDS Slot on the 6100 the same as the Quadras?

 

[NJRoadfan]

The DOS Compatibility Card likely doesn't use the same signals a PPC upgrade card for a 68k machine would use. The upgrade card's software/firmware likely can only "take over" from a 68k Quadra and would crash/barf if it encountered a PowerPC machine instead.

 

[eraser]

Bad idea.

The '040 uses a 32-bit data bus and the PowerPC 601 uses a 64-bit data bus.  Usually the PPC upgrade cards had a large amount of cache (1MB or so) to offset the slow Quadra RAM.  Taking that into consideration, the whole purpose of the PDS adapter for 6100 was to make the DOS card work.  That's it.  The signals that the PPC upgrade card would use to "take over" operations for a '040 probably aren't implemented at all.  

Even if you were somehow able to get this to work:

1. There would probably be performance and reliability problems because of the shuffle of your RAM from 64-bits to 32-bits to 64-bits.

2. The power load from both the adapter and the upgrade card with a full CPU and cache may be more than the circuitry was designed to handle.  (You may damage your logic board.)

3. It's unlikely the the adapter board runs at full PPC speed, but if it did then it would either make your upgrade card work at a faster-than-spec speed or cause weird timing problems.

4. G3 upgrades (even new in box) are cheap and readily available for this Mac.  They would be several times faster and more stable than this arrangement could ever possibly be.

In short, there is no upside to even trying this.

 

[eraser]

Then the question is or should be - is the PDS Slot on the 6100 the same as the Quadras?

No.  The right-angle adapter is required for the DOS card to work because has custom chips that pretend to be an '040 CPU.  100% of the data that comes into or out of the 601 PDS and the DOS Card is translated by the adapter.  

The same thing happens on the LC PowerMac systems.  They have a '040 PDS slot but if you look closely at the logic board you will see that the circuit traces from the "PDS" (it's not "processor direct" at all) slot all go to a chip on the board that fakes '040 signals … just like the right angle adapter here.  

CPU upgrades won't work on those slots either.

 

[wilykat]

Ok so it's useless to try. Since it'd be talking through a "fake" 040 between 2 PPC CPUs. Like 2 Harvard graduates trying to talk nuclear science while using an 8 year old to run back and forth to relay message to either person. Stuff would get lost in translation and the upgrade card would not work right and crash.

 

[olePigeon]

As the old phrase goes, if you can't explain particle physics to an 8 year old, you don't understand it yourself.

MicroMac did make an upgrade for the 6100 called the PowerBoy.  It was a 604 processor upgrade.