On Fri, 2005-09-02 at 18:25 -0500, Scott Stevens wrote:
I wouldn't call vacuum column drives an icon of
EARLY
computers...
I quote "IBM's Early Computers", by Bashe, Johnson,
Palmer, and Pugh, an
excellent book well worth reading:
"...the Type 726 tape units used in the 701 computer system, produced in
1953. They operated at 75 ips, with a tape-recording density of 100bpi."
http://www-03.ibm.com/ibm/history/exhibits/701/701_1415bx26.html
and as this picture shows, it was vacuum-column.
I believe the UNISERVO tape drive on the UNIVAC didn't use vac cols, but
then again... the tapes were metal.