Engineer's view. This is a database that rewrote the whole table file on every transaction so it could roll back. Real databases append each change to a log, checkpoint now and then, and roll back by truncating the log. A Mamba layer can store its state the same way.

TL;DR. A Mamba layer overwrites its state every token, so undoing a rejected guess needs a saved copy. At large batch sizes those copies cost more than speculation saves. Logging each token's inputs and checkpointing now and then makes undo a pointer move.

Explain Like I'm 5

You are writing a story on a whiteboard, and a friend guesses your next four words. You write them in. If a guess is wrong, you must erase back to where you were. On paper you just cross out the last words. On a whiteboard that gets wiped and redrawn every word, you need a photo of the board before each guess. Taking all those photos is slow.…