<There was a TRS-80 model 1 Zork that meets this description -- I bought <it years ago. It was a single-density disk (The model 1 used a 1771 <controller that could only do single desnity), and it was formatted <strangely 'copy protect' it. It was also a self-booting disk with no <filesystem as such -- the Zork program just read the text (encrypted <IIRC) from raw sectors on the disk. I think the trs80 boot code loaded on a few sectors that acutally booted and loaded ZORK as there were other things in the way of odd skewing and sector numbering the standard code didn't like. <Superutility on a TRS-80 could probably read/back up that disk, but I <don't know what else can. Or suprzap (or several others) on one of many systems using the older 1771 controller (S100, Bigboards and others). Allison