No! high level languages should not be used to write systems software

Abstract

The views expressed here derive from the experience of the author and his colleagues in designing and implementing the Octopus computer network at the Lawrence Livermore Laboratory. This network serves five major time-shared computers (CDC 7600's and STAR-100's), connecting them to over 800 interactive terminals, about 200 television monitor displays, printers that operate at up to 18,000 lines/minute, and more than a trillion bits of storage. The software for the network has been written entirely in assembly language (for PDP-8's, 10's, and 11's, MODCOMP II's, and TI 980's) and from scratch, basing none of it on manufacturers' or other commercial software. The same persons who create the design also do the programming and debugging. In most cases one or two persons program a computer; four persons were used on the largest system (the PDP-10's). Our experience does not accord with much of what we read in the computing literature, leading us to conclude that it is written by persons unaware the real problems of systems work. We have had little or no trouble with deadlocks, security loopholes, and other logical flaws that are belabored at length in the literature. Most of our effort has gone into devising ways for the system to survive in the presence of intermittent and random failures of hardware components and for it to maintain high data transfer rates among multiply-interconnected devices and computers of varying speeds, matters that are seldom discussed in the literature at all. It is certainly not the case that the difficulties encountered with operating systems are the same as those encountered with other large programs, such as compilers.