476 Part 5 The PMS level Section 4 Network computers and computer networks
The 7600 Pc can be interrupted by a clock, the PPU's, and trap condition within the Pc. A breakpoint address, BPA, can be set up within Pc such that, on the program reaching BPA, a trap is initiated. This interruption scheme is in contrast to that of the 6600, which could not be interrupted or trapped. The 7600 interrupt may be a reaction to the lack of intercommunication in the 6600.
Conclusions
Although the 6600 was somewhat behind its announced delivery schedule and represented a significant drain on the financial resources of CDC, it is now clear that it is a successful product. There have been instances of very large computers not being carried to completion either for financial or technical reasons. The 6600 seems to be the first large computer to achieve these marks of success. Here we are interested in the 6600 because it has held the "world's largest computer" title for so long.
Computer-network examples
In Chap. 40, we present examples of seven computer networks. There is a dearth of both computer networks and of papers on computer networks.
This chapter takes examples from papers and from knowledge of several existing or proposed networks.