i found this 8 inch floppy disk in a skip, many years ago (1998 or so),
from looking at the instruction leaflet in the box,
this disk was used to align the head(s) of a Dysan 360A or 360/2A 8 inch disk drive,
in conjunction with an oscilloscope.
(IMG:dysan360_1.jpg)(IMG:dysan360_2.jpg)(IMG:dysan360_3.jpg)(IMG:dysan360_4.jpg)(IMG:dysan360_5.jpg)(IMG:dysan360_6.jpg)(IMG:dysan360_7.jpg)(IMG:dysan360_8.jpg)(IMG:dysan360_9.jpg)(IMG:dysan360_10.jpg)