Deteriorated photo of a line of 2400 series tape drives. Several feet of tape were drawn into columns by vacuum to create slack so that the rapid starting and stopping of the reels wouldn't damage the tape. The tape motion was controlled by capstans and the reels, in turn, controlled by sensors in the vacuum columns. The three drives on the left have longer vacuum columns than the one on the right, indicating that they are faster models. The one on the right was a model 1 which read at 30,000 bytes per second. The others are either mod 2's or 3's which ran at 2 or 3 times the speed of the model 1. Tape density at this time was 800bpi, with options to handle lower densities for compatibility with earlier drives. Picture taken in 1967.