If you have had a PC your whole life, most likely its processor has been x86 architecture. Or x86 / 64 if it is recent. Its manufacturers, Intel or AMD, mostly. In case you have had Apple computers, you may have worked with different processors. From the first Motorola from the 80s to the PowerPC 90’s. If you’re not that old, you’ve had the odd Mac with a processor Intel. And if you just bought it, you may enjoy the M1 processors, manufactured by Apple itself. But let’s talk about CISC, RISC and ARM.

I mention Apple because its choice of processors for your computers serves to introduce this article: the war between two ways of designing a processor, CISC and RISC. In its early days, Apple opted for CISC-type processors (Motorola). Then it went to RISC with the IBM PowerPCs. Again, he went back to CISC with Intel and its x86 / 64. And finally, it has moved back to the RISC philosophy with its own M1s, based on the ARM architecture, of the RISC type.

In this war there is no clear winner. Both have had their share of the market. In the personal computer industry, somewhat chaotic, when IBM broke in with your PC, ended up imposing the CISC trend by popularizing Intel processors. But in professional or industrial sectors, RISC was on its way. Until the smartphones and other devices that required low energy consumption. The RISC architecture, represented by ARM, was imposed as the most efficient option. And today practically all mobile devices have processors of this type. To the point that personal computers start to use it too. Who knows what the trend will be in a few years.

Control panel of an IBM System 360 .. Author: Wolfgang Stief (Flickr)

First processor was CISC

In an article titled UNIVAC, the computer that inspired Asimov, I talked about the first computers. Among other things, I commented on the difficulty of defining a decade of the beginning of computing. But if we stick to computers as we think of them today, it may be that 1950s be a good starting point.

Back then, the first computers that could be used beyond scientific or military facilities. Still, they were very expensive, difficult to handle, and took up large rooms. You will have seen a photograph on the internet. Well, the way of being of those first thinking machines made the instructions that were given unique to that machine. Come on, you couldn’t use them on another.