[6] Attachment to a 709x system is through an IBM 7909 Data Channel and an IBM 7631 File Control unit, which can attach up to five random-access storage units, a mix of 7320 and 1301 DASD.
[6] The 7320 attaches to a System/360 through a channel and an 2841 Storage Control unit.
[8][9] The IBM 2301 is a magnetic drum storage device introduced in the late 1960s to "provide large capacity, direct access storage for IBM System/360 Models 65, 67, 75, or 85."
The vertically mounted drum rotates at around 3,500 revolutions per minute, and has a head-per-track access mechanism and a capacity of 4 MB.
The average access time is 8.6 ms, and the data transfer rate is 1,200,000 bytes per second.
The difference is that the 2303 reads and writes one physical track at a time, rather than the four in the 2301, reducing the data transfer rate to 312,500 bytes per second.