Well, the uassembler was a product for a while, so they must have.. I recently had the idea of programming them into an M792 ROM card (100nsec access time); user programs couldn't have used it without burning a segment (to map in the appropriate part of the I/O space), but it might have sped up the kernel some (and it would have been trivial to add, once the card was programmed - with a soldering iron - BTDT, BITD :-). Haven't gotten to it yet - still looking for an M792 (I don't want to trash any of my pre-programmed M792-xx's :-). Why not just write a Unix-native one? They aren't that much work - I created a uassembler overnight (literally!) for the QSIC project Dave Bridgham and I have been working on. It's been improved a lot since the first version (e.g. the entire uengine description is now read in from a config file, instead of being compiled in), but that first version did work fine... Or was the output format not documented? Noel