Slide 55 of 89
Here’s an overall block diagram of the 7600. Unlike the 6600, PPUs are not multi-threaded. Up to 15 PPUs can be connected and all 15 channels that connect to the central processing unit can operate in parallel. Some of the PPUs can be located in the CPU cabinet and others occupy separate racks.
By the way, disks and the drum were correspondingly small. A disk was only 40 Mbytes, and the drum was 20 Mbytes.