Frequently Asked Questions

  1. What is computer architecture?

    Computer architecture is the study of how computer systems are designed, built, and organized.1

  2. Why is it important?

    Faster, smaller, more power-efficient, and more domain-specific computing is a necessity in almost every field. Consider: mobile phones, wearable electronics, architectures for ML, scientific computing, low-latency networking, or simply running a web browser — all these are cases where building progressively "better" computer systems is critical.

  3. Why is it interesting?

    It's a complete answer to the question: "What's really inside your computer, and how does it work?"2

  4. What are the current challenges in computer architecture?

    In past years, the industry relied on Moore's law for improvement in computer speeds.3 Unfortunately, we're fast approaching the theoretical limit of transistor size, meaning we must rethink the architecture of computers to better utilize the resources we have available.

  5. I'm interested in computer architecture, where should I start learning?

    A great place to start is coming to SIGARCH meetings! Outside SIGARCH, there are various routes you can take.

    1. Classes: The ECE and CS departments at UIUC both offer classes in computer architecture and related topics:

      Class Content Comments
      ECE 120 Digital logic, basic computer organization, assembly programming. Uses LC-3. As a first course in computer architecture, covers extremely important fundamental concepts (critical paths, logic minimization, FSMs).
      CS 233 Basic Verilog4, basic computer organization, assembly programming and optimization. Uses MIPS. Lots of MIPS programming and learning how C compiles down. The honors section lets you build a project with FPGAs5 at the end.
      ECE 220 Interrupts and privilege. Mostly a programming class outside the first two weeks. Not really an architecture class outside what's mentioned. Though C is useful to know.
      ECE 385 SystemVerilog and FPGA class. One lab implements a subset of LC-3 on an FPGA. Class is being reworked as of SP23 to use Xilinx. Does not cover SystemVerilog in enough detail to do modern RTL design/verification.
      CS 433 Performance evaluation, ILP, caches, parallelism, multi-core. Some advanced topics on pipeline and cache optimization. No MPs, the class is homework and exam based. There are projects and presentations for both the undergraduate and graduate sections.
      ECE 411 Modern computer architecture: performance evaluation, caches, pipelining, memory systems, types of I/O, parallel processing, some advanced concepts. Uses RISC-V. Requires ECE 3916 (and you'll need to know SystemVerilog for the MPs). The final project is an excellent opportunity to build something ambitious.

      Outside these, there are various graduate courses offered each semester.

    2. Self-study: There are two parallel tracks to follow: learning theory and writing actual implementations. We'll elaborate on both of these:

      Theory: Here are some book recommendations:

      Projects/Implementation: Resources here are a bit more scarce:

      • An excellent route is to learn some Verilog. Try HDLBits while starting out. Unfortunately, the really hard part of RTL design is verification, which isn't well-covered.
      • Once you know Verilog, try implementing a basic processor (like LC-3), and running some basic programs in simulation.7 Synthesize your core to an FPGA, and run a similar set of programs there.
      • Continuing — pipeline your processor, implement a memory system, (caches). Make your cache more efficient (is it write-back? pipelined? lockup-free?). Add branch prediction. Add prefetching. Make it out-of-order. Is it superscalar? Instantiate multiple cores and solve coherence problems using snooping/directories. Add an MMU and TLBs. Try booting a real OS on your core (xv6, Linux, etc.). Implement a paper.

      We know, projects are hard and need resources that aren't always available. This is where SIGARCH's workshops come in: we provide hardware and guidance, and you get to implement something cool over a couple of days!



In contrast with computer science, which focuses on using computers to perform useful tasks.


Also, "can you make it better?"


The growing number of transistors on a single chip meant more computing power could fit into a single device.


(System)Verilog is a hardware description language (HDL) — a specialized computer language used to model and implement electronic circuits.


An FPGA (field-programmable gate array) is a chip that can be reprogrammed by software to behave like any digital circuit, specified using an HDL.


ECE 391 is a systems (not architecture) class. The prerequisite exists since 411 uses concepts such as virtual memory and TLBs that are covered in 391.


If you're more CS-oriented, writing a Python assembler or emulator is a fun extension of this project. Advanced: write an LLVM backend for your architecture so that you can run C on it.