[arp242]

They claimed it's not needed because Apple hardware is very good; from [1]:

"The APFS engineers I talked to cited strong ECC protection within Apple storage devices. Both flash SSDs and magnetic media HDDs use redundant data to detect and correct errors. The engineers contend that Apple devices basically don’t return bogus data."

Note this continues for a bit and criticises that position. Also see the HN discussion at the time: https://news.ycombinator.com/item?id=11934457

I don't think it's a good decision either; obviously you can run systems without checksums (we've been doing so for decades) but "netter safe than sorry" seems to be the smart thing. It's pretty cheap to checksum data, which is why all the next-gen filesystems (ZFS, btrfs, bcachefs) do so.

[1]: https://ahl.dtrace.org/2016/06/19/apfs-part1/

[frankjr]

Yeah it's strange and quite disappointing. Even if Apple devices never returned bogus data (doubtful), there's a whole industry of external disks, largely fuelled by Apple's ridiculous SSD prices, that you're putting APFS on and which are often of dubious quality. Then again, the interview is now 8 years old and they must have been working on something since.