The Emulator was a piece of software commissioned by Commodore and created by Ariadne Software which provided an environment in which OS legal software for the BBC Micro could run on an Amiga.
The Emulator was written in highly optimised 68000 assembler and as such, only runs natively and correctly on the Amiga A500 and Amiga A1000 computers.
The photo below shows The Emulator's disk contents running on an Amiga 1200 which is running Relokick to downgrade from Kickstart/Workbench 3.1 down to Kickstart/Workbench 1.3, alternatively you can use TUDE to disable all CPU caches and use the 'Privileged' option to get it running on later Amiga hardware.
When running on an A1200 even when downgraded using Relokick, The Emulator crashes predominantly when accessing files using commands such as CHAIN, and OPENIN or OPENOUT.
Once launched, The Emulator displays a set of banners and a prompt which should be reasonably familiar to anyone that owned or used a BBC Micro. The Emulator provides a total of 64K of RAM to user programs running within its environment and as such is more akin to a BBC Model B+ rather than the original BBC Model B.
Both the Ariadne DFS (Disk Furtling System - see the photo below) and BASIC ROMs were written entirely in 68k assembler and as such, the implementation of BASIC could run OS legal applications at a significant speed increase when compared to the original BBC Micro.
Below, you can see one of the bundled pieces of software which came with The Emulator which illustrates how the Teletext screen mode (MODE 7) was emulated.
When it's "The Emulator"! The Emulator as a piece of software is far from being a true emulation of a BBC Micro. Instead, it could be more accurately described as being a "simulator" as it simulates many aspects of the BBC Micro but due to the fact that the software is written in such a way as to be layered on top of the Amiga's native OS instead of providing a fully sandboxed environment, it isn't strictly an emulator at all. Ironic then that the name of the software is "The Emulator"!