I have a Mac IIci with no ROM in the ROM slot, but it works fine. What's the ROM slot for? Does it provide any advantages?
The advantages were only to Apple, read up on the "Dirty ROM" fiasco that occurred when the II & IIx (or IIx & SE30?) were released. It seems none could actually address the promised 32 bits of memory as shipped. A little company in Connecticut figured out the fix (Mode 32) and patented it, much to Apple's chagrin and even more to the benefit of that little company's coffers!
After that "undisclosed amount" settlement, Apple offered Mode 32 to its customers for free, in order to avoid a class action law suit. They also began installing an "auxiliary" ROM Slot on succeeding Macs "just in case" and as they proved more and more unnecessary, the lily livered boffins within the "Infinite Loop" continued to design "pads" for unimplemented sockets for quite a while thereafter.
Apparently it was embarassing to have an outfit like Connectix, pull the Royal Gems outta the fire for a Big@$$ payoff! [
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IIRC, of course!
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