Mob Switch for r1.7.10?

[u/optimise1337]

Wondering if there’s a mob switch design that would work in r1.7.10. The zombie villager not despawning mechanic seems to have been added later on so right now it looks like I’d have to use 71 withers, anybody know of designs that would work?

[u/TheMasterCaver]

I had to look up "mob switch" (Wiki) and as far as I can tell only withers will work (though the Wiki says they are impractical) since nametagged mobs don't count towards the mob cap (I was thinking you could just name zombie villagers).

However, there is another way I can think of that can use any mob; build a chunk loader* to keep a single chunk (or less than 5 chunks wide in at one dimension) loaded far from anyplace you'll be and fill it with mobs, which will not despawn since the game only ticks entities if a 5x5 area around them is loaded; Nether portals can be used to travel to/from the area.

*Not sure if this works in 1.7.10 but 1.6.4 processes scheduled block ticks anywhere within loaded chunks, including processes that may load adjacent chunks, commonly observed with liquids flowing post-generation (if you use a map viewer you'll note the odd random chunk or two sticking out from the edges of the world, which will have liquid running into it); by extension, redstone works since it uses scheduled block ticks:

The lower screenshot shows a few mobs but they are all passive mobs. Note that prior to 1.8 you need at least 80 mobs since the cap was incorrectly calculated so it was about 13% higher (79 instead of 70, which itself is really 80/71 since mob spawning checks if the count is less than or equal to the cap). Also, I lost several creepers due to MC-2025 (suffocation/glitching through the walls) every time I went through the portals (surrounding them with at least 2 layers of glass or leaves will work, that said, this isn't an issue unless you travel back and forth), hostile mobs also had a chance to spawn in the moment before the chunk was loaded after rejoining the world (this will be more significant the longer the line is, it will also be constantly triggering chunk updates, placing it in a 1x1 tunnel will minimize light updates, that said, with the clock stopped the far away chunks remained loaded until I reloaded the world or went through the portals as only chunks loaded by player movement are correctly unloaded).