Section 4 Network computers and computer networks 475
In a typical system, one might expect to find the following assignment of PCP's to be:
1 Operating-system execution, including scheduling and management of Cc and all Cio's
2 Display of job status data on T(display)
3 Ms(disk) transfer management
4 T(printers, card reader, card punch)
5 L(#1:3; to:C.satellite)
6 Ms(magnetic tape)
7 T(64 Teletypes)
8 Free to be used with Ms(disk) and Ms(magnetic tape)
9 Free
10 Free
CDC 7600
The CDC 7600 system is an upward compatible member of the CDC 6000 series. Although the main Pc in the 7600 is compatible with the main Pc of the 6600, instructions have been added for controlling the io section and for communicating between Large Core Memories/LCM and Small Core Memory/SCM. It is expected to compute at an average rate of four to six times a C('6600).
The PMS structure (Fig. 5) is substantially different from that of the 6600. The C('7600 Peripheral Processing Unit/PPU), unlike the C('6600 Peripheral and Control Processor)'s, has a loose coupling with the main C. The PPU's are under control of the main C when transferring words into SCM via K('Input-Output Section). The 15 C('PPU)s have S input/output channels. These channels, which can run concurrently, provide the link between C('PPU) and peripheral Ms's and Ts. Some of the PPUs are located in the same physical space as the Pc.
Fig. 5. CDC 7600 computer PMS diagram.