On May 8, 2015, at 11:51 PM, Billy Pettit <bpettitx
at comcast.net> wrote:
 ...
 These were great tape drives.  The 604 was 75ips versus 150ips for the 607.  ...
 These would be a good choice for recovering old 7 track tapes.  They used vacuum
tensioning columns and vacuum capstans.  So very little contact with the magnetic slurry
side of the tape. 
Vacuum columns done correctly ? not like the IBM error of putting the tape down the column
with the magnetic surface facing outward.  I remember that from our college 360 model 44.
        paul