On Wed, 2 Oct 2024, Tom Gardner wrote:
Speaking of high profit margins: on the 1620, there was an extra cost option called "direct seek". I don't know if involved a jumper cut or some actual circuitry (an adder, most likely). We didn't have that, and the result is that a seek from cylinder x to cylinder y was done by a full retract to cylinder 0, followed by a seek out to y. It was amusing to watch the shaking resulting from a simple "incrementing seek test" -- seek to cylinder i for i = 0 to 99. Those last few seeks would take the better part of a second.
Here's a link to a video that I took last year of a 1311 doing seeks (it is running on a 1401): https://www.youtube.com/watch?v=LXDVRP9pfyw
Christian
