Kernel (operating system) obsolete by virtually all operating system researchers. As a result, the design of Linux as a monolithic kernel rather than a microkernel was the topic of a famous debate between Linus Torvalds and Andrew Tanenbaum. There is merit on both sides of the argument presented in the Tanenbaum–Torvalds debate. Monolithic kernels are designed to have all of their code in the same address space (kernel space), which some developers argue is necessary to increase the performance of the system. Some developers also maintain that monolithic systems are extremely efficient if well written. The monolithic model tends to be more efficient
Cray Operating System Cray Operating System The Cray Operating System (COS) succeeded Chippewa Operating System (shipped with earlier computer systems CDC 6000 series and CDC 7600) and is Cray Research's now discontinued proprietary operating system for its Cray-1 (1976) and Cray X-MP supercomputers, and those platforms' main OS until replaced by UNICOS in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal. As COS was written by ex-Control Data employees, its command language and internal organization bore strong resemblance to the SCOPE operating system on the CDC 7600 and before that EXEC*8 from CDC's earlier ERA/Univac