Even iPhones aren't immune to getting bad blocks. The system files category is a catch-all that includes the reserved blocks for remapping by FTL when blocks go bad. As storage tiers get bigger, so does the number of reserved cells, in absolute terms.

If you read the article, the same is true in the SanDisk case. The module is still a 16 GB module, and “A portion of the total capacity is used to store certain functions including optimizations of the memory that support performance and endurance and therefore is not available for user storage.”

I think it's slightly different in that it changed though. A 16gb iPhone always meant that there was a 16gb storage module inside the device and then some of it was used for the OS (how much of it has varied over time however, which I agree is a problem)

In the sandisk case, at least from what I understand, it that 16Gb used to mean like a 17Gb module, with 1Gb used for system functions, now it's a 16Gb module with 1Gb used for system functions

Since there are no 17 GB modules (to my knowledge), they would have had to combine modules of different sizes. The f3 output in the article also states 16 GB for both drives. The old drive already only exposed 14.9 GB (GiB) of usable space. So it seems to me that is is only a quantitative change, not a qualitative one.

Phones are actually worse in that a mere OS update can decrease the amount of free space, which is something that presumably does not happen with USB drive firmware updates.

Are all the sizes really that even? Despite weird layer counts and stacking counts and typically doing 3 bits per cell?

Still, a 16GiB module would be 17 billion bytes. No need to combine different sizes. Unless you're saying a single module would have a decimal capacity?

If you take a 16GiB module and sell it as 16 billion bytes then that gives you 7% overprovisioning. Overprovisioning 10% would give you a 15.4 billion byte drive. If you want 16GiB then it's a quantitative change of how much you lose. But if you go by their promise of 16 billion bytes then it's a qualitative change that they broke the promise.

Why do I as the user care about how much storage is physically on the system? Are they going to start counting the firmware storage on the WiFi chip next?

As the user I care about how much storage I can use, and how durable it is. If the storage is used by the OS it isn't helpful to me, other than the "runs iOS" feature point.

(This does get slightly complicated if the OS space changes with updates, what number is best to explain to the user in this case. It isn't entirely clear but I can ensure you that if an OS update takes 30GiB more space users aren't going to care that that storage is still in their phone)

I really would love if phones shipped with discrete memory chips for the OS and user storage, so my '64gb' phone actually presents that to me.

Most Android phones use separate partitions for OS and user data so they could advertise how much user storage they are giving you (as they are very unlikely to re-partition during an update). However AFAIK all manufactures report the full storage size, not just user storage.

> Why do I as the user care about how much storage is physically on the system? Are they going to start counting the firmware storage on the WiFi chip next?

Damn man, don't give them ideas.