I've been really curious precisely what changed, and what sort of optimization might have been involved here.
Because offhand, I know you could do things like cute optimizations of redundant data to minimize seek time on optical media, but with HDDs, you get no promises about layout to optimize around...
The only thing I can think of is if it was literally something as inane as checking the "store deduplicated by hash" option in the build, on a tree with copies of assets scattered everywhere, and it was just nobody had ever checked if the fear around the option was based on outcomes.
(I know they said in the original blog post that it was based around fears of client performance impact, but the whole reason I'm staring at that is that if it's just a deduplication table at storage time, the client shouldn't...care? It's not writing to the game data archives, it's just looking stuff up either way...)
HDDs also have a spinning medium and a read head , so the optimization is similar to optical media like CDs.
Let’s say you have UI textures that you always need, common player models and textures, the battle music, but world geometry and monsters change per stage. Create an archive file (pak, wad, …) for each stage, duplicating UI, player and battle music assets into each archive. This makes it so that you fully utilize HDD pages (some small config file won’t fill 4kb filesystem pages or even the smaller disk sectors). All the data of one stage will be read into disk cache in one fell swoop as well.
On optical media like CDs one would even put some data closer to the middle or on the outer edge of the disc because the reading speed is different due to the linear velocity.
This is an optimization for bandwidth at the cost of size (which often wasn’t a problem because the medium wasn’t filled anyway)
I'm not entirely clear what you're trying to say, but, my understanding is that they simply put lots of copies of files in lots of places like games have done for a long time, in the hopes it would lower seek times on HDDs for those players who use them.
They realised, after a lot of players asking, that it wasn't necessary, and probably had less of an impact than they thought.
They removed the duplicates, and drastically cut the install size. I updated last night, and the update alone was larger than the entire game after this deduplication run, so I'll be opting in to the Beta ASAP.
It's been almost a decade since I ran spinning rust in a desktop, and while I admire their efforts to support shitty hardware, who's playing this on a machine good enough to play but can't afford £60 for a basic SSD for their game storage?