Actually worked on a 727 drive
Lots of vacuum tubes and all that. 200 bytes per inch on "standard" 1/2 inch tape. They took 2400 foot (10.5 inch) reels. The 727 had a nice feature that if you went far enough into the reel and asked for a rewind, it would "de-mount" the tape (wind out of the columns and raise the tape head) and rewind until it got closer to the beginning of the tape. Generally you didn't want to be just on the far side of the dividing point as the mount/de-mount sequence took quite a bit of time.
For the curious: The tapes (two fo them) were interfaced to an IBM 1620. Great fun (it was the 60's)!!