Every storage medium, including ram, benefits from sequential access. But it doesn't have to be super long sequential access, the seek time, or block open time just needs to be short relative to the next block read.

Unfortunately this actually is believable. SMH.

I haven't found any asynchronous IOPS numbers on HDDS anywhere. The internet IOPs are just 1000ms/seek time with a 8ms seek time for moving from the outer to the inner track, which is only really relevant for the synchronous file IO case.

For asynchronous IO you can just do inward/outward passes to amortize the seek time over multiple files.

While it may not have been obvious, I have taken archiving or bundling of assets into a bigger file for granted. The obvious benefit is that the HDD knows that it should store game files continuously. This has nothing to do with file duplication though and is a somewhat irrelevant topic, because it costs nothing and only has benefits.

The asynchronous file IO case for bundled files is even better, since you can just hand over the internal file offsets to the async file IO operations and get all the relevant data in parallel so your only constraint is deciding on an optimal lower bound for the block size, which is high for HDDs and low for SSDs.

No, not at all. But by putting every asset a level (for example) needs in the same file, you can pretty much guarantee you can read it all sequentially without additional seeks.

That does force you to duplicate some assets a lot. It's also more important the slower your seeks are. This technique is perfect for disc media, since it has a fixed physical size (so wasting space on it is irrelevant) and slow seeks.

Not really. But when you write a large file at once (like with an installer), you'll tend to get a good amount of sequential allocation (unless your free space is highly fragmented). If you load that large file sequentially, you benefit from drive read ahead and OS read ahead --- when the file is fragmented, the OS will issue speculative reads for the next fragment automatically and hide some of the latency.

If you break it up into smaller files, those are likely to be allocated all over the disk; plus you'll have delays on reading because windows defender makes opening files slow. If you have a single large file that contains all resources, even if that file is mostly sequential, there will be sections that you don't need, and read ahead cache may work against you, as it will tend to read things you don't need.

I assume asset reads nowadays are much heavier than 4 kB though, specially if assets meant to be loaded together are bundled together in one file. So games now should be spending less time seeking relative to their total read size. Combined with HDD caches and parallel reads, this practice of duplicating over 100 GBs across bundles is most likely a cargo-cult by now.

Which makes me think: Has there been any advances in disk scheduling in the last decade?

Their technique makes it so that the normal person with a ~base SSD of 512 GB can't reasonably install the game. Heck of a job Brownie.