Domesday
2010
VFS Utilities
ROM
I'm not sure how you organise your programming data, but this screenshot gives a flavour of how I do it. Everything is saved on some disc or other, in this case it's a floppy disc I'm using in the drive connected to Domesday 2010, but sometimes it might be a Winchester Disc or Econet file server. I use ADFS (or Econet) wherever possible because you can have directories and sub-directories and longer file names and greater disc capacity than using DFS.
UROM is the ROM image itself, and UROM/src is the source code, written in BBC BASIC assembler, with a couple of backup copies for those occasions when you forget yourself and type SAVE when you've just pressed CTRL-BREAK!
Disc space permitting, I like to keep track of all the versions of whatever I'm working on, so I put a copy of each "release" in a sub-directory called "Vers".