David Patterson on RISC Architecture, RAID, and the Evolution of Computing

The episode features David Patterson, a Turing Award winner, discussing the profound transformation of computing over the last 50 years, primarily driven by the invention of the microprocessor. He details how computers evolved from room-sized machines to ubiquitous devices like cell phones, becoming millions of times faster, cheaper, and more pervasive. Patterson breaks down the fundamental components of a computer—input, output, memory, and the processor (comprising the control unit and arithmetic logic unit)—explaining how the microprocessor integrates these elements onto a single chip. A central theme is Moore's Law, which accurately predicted the exponential growth in transistor density and its far-reaching implications for technology's integration into daily life.

Patterson elaborates on the critical concept of layers of abstraction in computer science, highlighting how this methodology manages complexity in both hardware and software, allowing engineers to focus on specific interfaces without needing to understand every underlying detail. He discusses the shift towards open-source hardware, particularly the instruction set architecture (ISA), contrasting proprietary ISAs like Intel's x86 and ARM with the open-source RISC-V. A significant portion of the conversation revolves around the historic "RISC vs. CISC" debate, where Patterson, a pioneer of RISC (Reduced Instruction Set Computer), explains why simpler, faster-executing instructions, managed by compilers, ultimately proved more efficient than complex instructions, despite initial industry skepticism.

The discussion provides insights into the art and science of designing an instruction set, emphasizing the delicate balance between hardware simplicity, execution speed, and compiler efficiency. Patterson notes that while CISC architectures like x86 initially dominated the business world due to established software bases, Intel cleverly adapted by translating complex instructions into RISC-like micro-operations in hardware, thus benefiting from RISC principles while maintaining compatibility. He also highlights the importance of quantitative analysis in computer architecture, a methodology he and John Hennessy championed through their textbook, using benchmarks and performance formulas to objectively compare and improve designs.

The episode underscores the continuous evolution of computing, driven by fundamental principles like Moore's Law and architectural innovations like RISC. It touches upon the philosophical implications of technology's pervasive integration into society, from the early "alien writing" of URLs to the current era of ubiquitous smart devices. The shift towards open-source hardware, exemplified by RISC-V, suggests a future where deeper understanding and customization of computing foundations become more accessible, potentially democratizing hardware innovation and fostering new advancements across various fields.

The biggest thing that happened was the invention of the microprocessor so computers that used to fill up several rooms could fit inside your cell phone and not only and how do they get smaller they got a lot faster so they're million times faster than they were 50 years ago and they're much cheaper and they're RIBA covetous.

A microprocessor simply means a process of the fits on a microchip and that was invented at about you know 40 years ago was the first microprocessor.

The fundamental driving force is what scored Moore's law which was named after Gordon Moore who's a Berkeley alumnus and he made this observation very early in what are called semi conductors.

I think that's one of the things that computer science fundamentals is the these things are really complicated in the way we cope with complicated software and complicated hardware is these layers of abstraction.

What open source means is what the engineer the programmer designs it's not secret the belonging to a company it's up there on the World Wide Web so you can see it.

The new idea that got started at Berkeley kind of unintentionally ten years ago is in early in my career we pioneered a way to do of these vocabularies instruction sets that was very controversial at the time.

We said for microprocessors which with Gordon's Moore is changing really fast we think it's better to have a pretty simple set of instructions reduced set of instructions that that would be a better way to build microprocessors since they're going to be changing so fast due to Moore's law.

It ended up that we ended up executing maybe 50 percent more instructions maybe 1/3 more instructions but they ran four times faster so so this risk controversial risk ideas proved to be maybe factors of three or four better.

Intel did cleverly and amazingly is they had their chips in hardware do a translation step they would take these complex instructions and translate them into essentially in RISC instructions in Hardware on the fly.

I think designing a goods instruction set as an art and I think you're trying to balance the the simplicity and speed of execution with how well easy it will be for compilers to use it.

We went from textbooks that kind of listed so here's what this computer does and here's the pros and cons and here's what this computer doesn't pros and cons to something where there were formulas in equations where you could measure things.