Why the old way is painfully slow.

Video transcript

The old way reads one word at a time. Why is that slow?

Picture one worker moving along the sentence. To handle the third word, he needs the notes from the second.

So he can't skip ahead. Every step waits for the one before it.

So six words take six steps. A thousand words would take a thousand steps in a row?

Exactly. Now imagine a worker on every word, all working at the same moment.

Then it would take just one step, no matter how long the sentence is? How many rounds would six words need?

Yes, one round. Nobody waits, so the whole sentence is done together.

That's the problem with the old way. It forces a line, even when many workers are available.