Shown here is a close-up of dual
access arms used to record data on or read data
from the IBM 350 disk memory unit in an IBM 305
RAMAC. The second access arm, available as an additional
feature, made it possible for one access unit to
be in a position for reading or writing while the
other arm moved to the next storage record. As both
arms could be in motion simultaneously, RAMAC processing
time was substantially reduced. The disk unit for
305 systems could be obtained with storage capacities
of five million digits and 10 million digits, and
could be installed either singly or in pairs.