Roller reefing where the boom is rotated and the sail wrapped around the outside was popular 60 plus years ago. It was almost instantly abandoned when slab reefing became popular. Roller reefing is a terrible system that results in a terribly shaped mainsail
can quickly ruin a sail by stretching out the leach. As you roll the sail, leech takes more and more of the load while the center of the sail turns into a big bag. Just the opposite of what you want when you reef a sail. People used to throw cushions
, PFDs, etc, into the center of the sail as it was being rolled to try and lessen the bag. At the gooseneck, the sail slides and and luff reinforcing builds up forcing the tack further away from the mast adding to the ballooning of the middle portion. If you hauled in the mainsheet in an effort to reduce the bag, all the force was on the leech could ruin a sail by stretching the luff in one reefing session. What is really puzzling is how this most atrocious reefing system ever gained popularity. Last but not least, it was not quick or easy to roll in a reef. You had to fight the luff buildup at the gooseneck and try and keep the leech from moving forward and adding to the balloon in the middle of the sail. Had it on my first boat in 1970 and ruined the main after one trip to Maui from HNL. Reefing with it was so bad that I soon abandoned roller reefing entirely and just dropped the main when I needed to mainsail area.
When roller reefing was popular, you could buy horse shoe shaped collar fittings to be able to attach tackle to a roller reefed sail. The 'C' shaped collar slipped onto the boom from the end. The opening in the 'C' was smaller than the width of the boom so you could use the fitting to put a down load on the boom. The Allowed vanging the sail down with boom to deck
blocks. The problem with this system was it had a tendency to put holes in the main where the two arms of the 'C' rested on the boom and rolled sail. Before the rigid at the mast vangs were invented, that's the way mainsails were vanged to reduce twist. Still use it on my boat because I wanted to be able to use the real estate aft of the mast. The limited height of the boom off the deck would have made for very high compression
loads on the goose neck as well which made me shy away from a rigid vang.
Roller reefing is not the same as in boom roller furling. It is possible to get a decent setting reefed sail with inboom reefing but comes at a very high cost in hardware
and requires critical maintenance
of boom angle to work properly.
Slab/jiffy reefing is so easy to do and works so well, see no reason to abandon it.
Have seen some boats that furl, not reef, the sail by rolling the main sail around the boom. It's just a way to store a sail rather than flaking it on top of the boom.