To put this into perspective, the 380Z and 480Z ran WordStar, the early CP/M based word processor, in less than 48Kb memory
To put it more into perspective ... when we first used 380Z's the RM screen editor TXED was considered to be an insanely enourmous program because its image was something like 12kB!
However, even that was somewhat bloated ... there was an idea at school to start teaching pascal and there was a pascal system for 380Z (Transam Pascal I think) but its main blocking point was that to input programs you had to use an EDLIN style line editor which was horible. Somehow we found out the as far as the rest of the pascal system was concerned the "editor" was used a piece of code that sat in a 2kB block of the RAM which was called and edit test in another defined block of memory - so anything that was 2kB or less could be used as the editor if it was patched into the image. We suggested to RM that a cut down TXED with be great but they said that wasn't possible but after a bit of cajolling they handed us the source code and said we should do it ourselves if we thought it was possible ... so I got to take a 380Z home with me over the summer holidays along with the TXED source code (all Z80 assembler) and by a process of removing editor commands that weren't needed and eliminating all the now redundanty code I eventually managed to get a fully function screen editor that was slightly under 2kB in size!
Via school contacts I almost got to work for RM duing my post-Oxbridge/pre-University "year" (we did post-A level Oxbridge so you ended with Jan-Sep to fill before University started) but that coincided with the Small/Fischer falling out so the school contacts managed to get me an alternative at Acorn during the build up to the BBC micro launch