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16MB SIMMs in Mac Classic II?

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Everyone likes to talk about how the SE/30 can go to 128MB of RAM and is a wonderful flexible machine with the Mac ROMinator II, etc.


But has anyone tried putting those 16MB SIMMs into the two-slot Classic II logic board? Pushing it to 34MB of RAM would be cool.


If it's a ROM limitation, though, then I ask - 


Is there the possibility of a Mac ROMinator III for the Classic II that would replace the ROM chips rather than be simply on a ROM SIMM? (Kind of a later version of the ROMinator I) Steve? Doug?

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It's my understanding that the Classic II is built on the Macintosh LC/LC II architecture. The memory controller/bus interface controller called "Eagle" can only physically address 10mb of RAM. The 68030 is sitting on a 16-bit data bus as well, further crippling the machine. Fundamentally there is no way around the physical restrictions of the Eagle chip.


The SE/30 ended up expandable because it is based off of the IIcx architecture and was not crippled from day 1.

Edited by IIfx
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Maybe not intentionally crippled, but it had its own issues.


Limiting a Compact form factor version of the 32bit/Color ROM Macintosh IIx/IIcx to the SE's 68000 architecture A/B, not implementing at least a subset of the ancient (by that time) Macintosh II Toby frame buffer card and then just hanging the 128K Mac 68000 16bit architecture's B&W neck board off the CRT, rather than implementing internal grayscale from day one was a severe limitation.


Considering the price differential and cost/benefits of GS in the era of Desktop Publishing, Apple was remiss in its laming of the SE/30 with so many of the underperforming SE's guts.




Back on topic: Reworking the minimalist memory expansion card of the Classics to add an additional pair of slots for 16MB MB SIMMs acting as a VM RAM Disk under Compact Virtual as was done on so many 16bit bus SE accelerators might be an interesting project.


I'd be surprised if the Eagle ASIC lacks the legs to do the job, a single(?) jumper wire might do the trick. A hack upgrading to the LCIII memory controller might be necessary?


Dunno, interesting topic, gogopuffs!  [;)]]'> 

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