The most interesting things here are disk images for the Master "512", which despite the name was a fairly normal Master 128 only with the addition of an Intel

The most interesting things here are disk images for the Master "512", which despite the name was a fairly normal Master 128 only with the addition of an Intel 80186 co-processor, carrying 512k of RAM on its own board. It could boot "DOS Plus", a DOS clone from Digital Research that included the GEM desktop. Unfortunately it was compatible with very little DOS software, being system call compatible only up to MS-DOS 2.1, and having a non-standard keyboard and display. As far as I know Acorn only shifted any significant amount of stock after they slashed the price, and I wonder even then how many buyers thought they were getting a BBC Master with 512k of RAM. I suspect most of the copro cards went unused. Today, if you have a Master 128 and want to "upgrade" it, you can run PiTubeDirect on a Raspberry Pi which will cause it to emulate the appropriate 80186 (amongst other choices), so you can plug it into the Tube socket on the Master: https://github.com/hoglet67/PiTubeDirect https://github.com/hoglet67/PiTubeDirect