Originally posted by JMS
The IBM PC which Sam explicitely stated.. "Original PC" was the one which came with 64k and was upgradable to 256..
I had an "Original PC"! I upgraded it with a memory board with 2 MB on the board. The 256 KB limit was for the system board (also known as the motherboard).

In PC Memory Organization the memory layout above 640 KB is clearly shown. It clearly says that the original 8086 IBM PC had an address range of one megabyte.

Note that when a 8086/8088 powers up or is reset, the first instruction executed is at address 0xFFFF0. This is fixed by the processor; there must be something there. The IBM PC BIOS is at that high end of storage.

In IBM PC the original IBM PC is shown and described. It looks just like the one I had. Look at what that article says about Memory.

The Limitations of the IBM PC Architecture article also clearly says that the PC has an address space of 1M byte. It also says that "The space between 640K and 1M is reserved for hardware and operating system use."; in other words, it does exist for a PC and is not available for general use. Look at what it says about "bank-select memory systems"; it describes expanded memory quite well as it originally existed and developed. I think it is also makes it clear that expanded memory preceded the 286.
Originally posted by JMS
There was no such thing as memory above 640k until after the 286 was introduced extended memory.
As explained above, a PC must have memory above 640 KB for BIOS ROM and for video RAM.

Originally posted by JMS
Expanded memory of the 386 is associated with the 8088 because the 386 running in protected mode was said to "emulate" multiple 8088 sessions and thus make the extra memory availible to real mode programs... ... But those real mode programs running the expanded memory were running on a 386 emulating an 8088 not actually on an 8088....
Why would anyone want to do that? What did expanded memory do that made it useful? Do you know anything about how expanded memory works? I provided an article above that describes how expanded memory works; can you find something that describes expanded memory differently? The only reason to emulate expanded memory using a 386 or higher processor is to support programs that are written that require it.
Originally posted by JMS
I hope we can agree that my original post was not misleading...
I don't .