| • | This is RAM that appears past the 1 MB address (in the motherboard's address space). |
| • | In IBM documentation and software, IBM refers to this as 'expansion' memory. Do not confuse 'expansion' with 'expanded'. |
| • | Extended memory must start at the 1 MB address, and be contiguous (no gaps). |
| • | Do not confuse extended memory with the Extended Memory Specification (XMS). Extended memory is physical; you can touch it. XMS is a software interface, providing controlled access to extended memory (e.g. via HIMEM.SYS) |
| • | The WikiPedia article is here. |