CS 315-01 Lecture/Lab (Fall 2025) — Meeting Summary

• Date: Dec 02, 2025
• Time: 08:18 AM Pacific (US and Canada)
• Zoom ID: 886 4953 2573

Quick Recap

• Status updates on Project 7 and a review of advanced computer architecture (speculative and out-of-order execution).
• Discussion of security vulnerabilities in modern CPUs (Spectre, Meltdown) and their implications.
• Final exam preparation: format, scope, practice resources, and grading policy. The final is worth 35% of the course grade.
• Technical issues with Project 6 were reviewed; debugging guidance was provided.
• Late submission policies for Project 5 were clarified.

Next Steps (Greg)

• Investigate Killian’s Project 6 issue (nested directories and missing instruction memory ROM).
• Run one-week-late grading for Project 5.
• Run greater-than-one-week-late grading at semester end.
• Post solutions to final exam practice questions.
• Bring donuts and coffee to the final exam (Tuesday, 7:30 AM).
• Update the immediate decoder in final exam practice problems.

Topic Summaries

Project 7 and Architecture Review

• The session covered:
• Project 7 updates.
• Advanced architectural concepts beyond the course core.
• Final exam practice question solutions to be posted.
• A technical discussion examined a hazard unit and logic for stalling; implementation issues were noted.

RISC-V Processor: Course Capstone and Final Review

• Emphasis on the progression from fundamentals to a working RISC-V processor.
• Overview of privileged instructions and OS-level isolation/resource management (with deeper coverage in CS 326).
• Takeaway: Understanding real-world software complexity requires a solid architecture foundation.

Modern Processor Design Evolution

• Compared basic digital designs with modern CPUs featuring:
• Speculative execution.
• Out-of-order execution.
• Overlapped/parallel instruction paths for efficiency.
• Reviewed Spectre and Meltdown:
• Exploit speculative execution to leak sensitive data.
• Understanding these is essential for modern computing.

Side-Channel Attack Vulnerabilities

• Spectre-class attacks use cache state and timing to infer cross-process information.
• Mitigations exist, but core behaviors in CPU design make complete fixes difficult.
• Research continues to reveal new variants.

Security vs. Performance in CPUs

• Ongoing trade-off: stronger defenses can significantly impact performance.
• Class discussion included a Project 6 issue (post-unnesting, autograder failed due to deleted instruction memory); Greg will investigate.

Project Policies and Final Exam Details

• Late policy for Project 5:
• Within one week late: 75% credit.
• Later (but before semester end): up to 50% credit.
• Project 6 debugging guidance:
• Inspect forwarding paths and control lines; verify instruction memory/ROM integrity.
• Final exam:
• Time: Tuesday at 7:30 AM.
• Weight: 35% of the course grade.
• Notes: Two pages allowed.
• Grade improvement option: If the final is stronger, the midterm may be replaced by the average of the midterm and final.

Final Exam Preparation Overview

• No full practice final will be posted.
• Recommended resources:
• Practice midterm.
• Lab 11 (mirrors the final’s scope and sequence).
• Coverage: All lectures, labs, and assignments.
• Format: Short-answer and computational problems.
• Reviewed sample problems (e.g., sum-of-products, digital design).
• Clarifications addressed:
• Notation expectations.
• Architectural limits such as maximum supported instructions and the number of registers that can be updated per clock cycle.
• Students were encouraged to attend office hours with questions and to stay on track with Project 7.