[jorticka]

It would be easy for competition to reverse engineer the physical layout.

I think it's "secret" because nobody really cares.

Do you care for example how the CPU maps the linear memory space across physical RAM sticks and chips? I recently discovered that there multiple alternatives and BIOS settings which give you some control over this.

[ipython]

People absolutely care!

You can't cheat physics, so at today's CPU speeds, spinning disk HDDs more closely resemble tape drives than not. You have to pay a significant performance price when moving the read head across the disk surface, moreso when you have to wait an entire rotation for the correct sector to fly under the read head.

[HPsquared]

Dual channel is a thing, I suppose. Probably similar for hard drives: multiple heads, there might be some micro-trickery to align things just right.

[jorticka]

I wasn't talking about dual channel, but something else. There are a number of ways to map linear memory space to multiple individual memory chips.