I am the user David speaks of here, but independently of that, I have the first suggestion for reducing messages.
Drive 0 Cyl 0->30 select 3, head 7 dirty 0
Waiting, seek time 7.2 ms max 7.2 min free buffers 75
Drive 0 Cyl 30->29 select 3, head 7 dirty 0
Waiting, seek time 1.8 ms max 7.2 min free buffers 75
Drive 0 Cyl 29->27 select 3, head 7 dirty 0
Waiting, seek time 0.3 ms max 7.2 min free buffers 75
Drive 0 Cyl 27->23 select 3, head 7 dirty 0
Waiting, seek time 1.4 ms max 7.2 min free buffers 75
Drive 0 Cyl 23->21 select 3, head 7 dirty 0
Waiting, seek time 2.5 ms max 7.2 min free buffers 75
Drive 0 Cyl 21->19 select 3, head 7 dirty 0
Waiting, seek time 0.4 ms max 7.2 min free buffers 75
Drive 0 Cyl 19->16 select 3, head 7 dirty 0
Waiting, seek time 2.9 ms max 7.2 min free buffers 75
Drive 0 Cyl 16->12 select 3, head 7 dirty 0
Waiting, seek time 1.1 ms max 7.2 min free buffers 75
Drive 0 Cyl 12->9 select 3, head 7 dirty 0
Waiting, seek time 2.8 ms max 7.2 min free buffers 75
But what if we remove the "Waiting, seek time..." messages, so it only looks like this?
Drive 0 Cyl 0->30 select 3, head 7 dirty 0
Drive 0 Cyl 30->29 select 3, head 7 dirty 0
Drive 0 Cyl 29->27 select 3, head 7 dirty 0
Drive 0 Cyl 27->23 select 3, head 7 dirty 0
Drive 0 Cyl 23->21 select 3, head 7 dirty 0
Drive 0 Cyl 21->19 select 3, head 7 dirty 0
Drive 0 Cyl 19->16 select 3, head 7 dirty 0
Drive 0 Cyl 16->12 select 3, head 7 dirty 0
Drive 0 Cyl 12->9 select 3, head 7 dirty 0
In some of my testing, I've done this after copying the console to text file, I wrote a text file modification basic program to remove all of these lines, so that I could easily scroll through the output and much more easily visually see the history of the Cylinders and heads selected as I scrolled.
Those are my first thoughts on reducing output in a meaningful way.