They manage the hardware bits (rotation speed, head movement, etc) but they don't present much of an abstraction layer over that (they do remap bad blocks). The

They manage the hardware bits (rotation speed, head movement, etc) but they don't present much of an abstraction layer over that (they do remap bad blocks). The SSD equivalent would be a firmware that just presents the block structure with wear counters per block and possibly does the read-modify-write dance for writes smaller than a block and remaps broken blocks to a few it keeps hidden. All the other wear leveling stuff it can just let the OS handle.