Section 4 Network computers and computer networks 471
Fig. 1. RW-40 (Polymorphic) PMS diagram.
component count almost implies it cannot exist as an operational entity. Thus it is a tribute to an organization, and the project leader-designer Seymour Cray, that a large number exist. There are sufficiently high data bandwidths within the system so that it remains balanced for most job mixes (an uncommon feature in large C's). It has high performance Ms.disks and T.displays to avoid bottlenecks. The Pc's ISP is a nice variation of the general-registers processor and allows for very efficient encoding of programs. The Pc is nicely multiprogrammed and can be switched from job to job more quickly than any other computer. Ten smaller C's control the main Pc and allow it to spend time on useful (billable) work rather than its own administration. The independent multiple data operators in the 6600 increase the speed by at least 21/2 times over a 6400 which has a shared D. Finally, it realizes the 10 C's in a unique, interesting, and efficient manner. Not many computer systems can claim half as many innovations.
A simplified PMS structure of the C('6400, '6600) is given in Fig. 2. Here we see the C(io; # 1:10) each of which can access the central computer (Cc) primary memory (Mp). Figure 2 shows
Fig. 2. CDC 6600 PMS diagram (simplified).