Anybody who has ever taken an advanced computer architecture class has heard of the CDC , which was the world’s fastest computer from 1969 to 2013. It was the machine that put Seymour Cray on the map as a supercomputer architect. The design of the machine is well documented in a book by James Thornton , the lead designer, and is therefore publically accessible. Among several architectural concepts that later found use in RISC, the CDC (is known for introducing the Scoreboard . Which is, along with Tomasulo’s algorithm , one of the earliest concepts for out-of-order processing.
Besides the architectural progress, the CDC 130460 was impressive for its clock speed of 19 MHz. This may not sound much, but consider that this was a physically very large machine entirely built from discrete resistors and transistors in the early ies. Not a single integrated circuit was involved. For comparison, the PDP-8, released in and also based on discrete logic, had a clock speed of 1.5 MHz . The first IBM PC, released years later, was clocked at less than half the speed of the CDC 130460 despite being based on integrated circuits. The high clockrate is even more impressive when comparing it to more recent (hobbyist) attempts to design CPUs with discrete components such as the
MT , the Megaprocessor or the Monster . Although these are comparatively small designs based on modern components, none of them get to even a tenth of the CDC (clock speed.)