DNA Printers, or a technique known as "solid phase synthesis" is a different technology that was used by the HGP, but not developed or advanced by them.
I remember using these 20 years ago to make RNA (they can make RNA as well as DNA, if you add the right reagents, which IIRC were obscenely expensive). They'd run with various pumps and relays clicking. I got 40 OD of a single RNA duplex, and proceeded to... wash it down the drain, since I was an idiot in the lab.
By "making... cheap" the mechanism I meant was it drastically increased the market size for genomics, and thus ushered in economies of scale in these technologies.
