# Postmortem: Serial Data Corruption in Windows API Read ## A C++ application using Windows API for serial communication experienced intermittent data corruption when reading from an Arduino device. Data was clean only when Arduino’s transmission delay was excessively high (1000ms), making real-time control impractical. ## Root Mismatched serial configuration between Arduino and C++ application: … Read more
# Postmortem: Biased Model Training with EEG Signals ## Persistent model bias observed during training on EEG dataset for wheelchair navigation commands: – Models consistently best identified `stop/neutral` → moderately performed on `forward/left` → consistently failed on `right` – Observed across MATLAB Classification Learner models and custom – Best outcomes: ~50% accuracy for problematic classes … Read more
# The Cache Miss Illusion: When Out-of-Order Execution Masks Real ## We investigated the misconception that cache misses consistently cause severe pipeline stalls in out-of-order (OOO) CPUs. While cache misses do incur latency, OOO execution often hides this cost by continuing unrelated work—misleading profiling tools and engineers into misidentifying optimization targets. ## Root – **Misinterpretation … Read more
# Postmortem: Performance Bottleneck in Repeated Python Function Calls from ## A performance-critical data processing pipeline experienced significant slowdowns when integrating Python-calculated variables into an R dataframe using reticulate and dplyr. The implementation repeatedly called the same Python function 7 times per group to extract individual output elements, leading to unnecessary computation. ## Root – … Read more
# Postmortem: Unstable Clock Signal in JK Flip-Flop LED ## When constructing a JK flip-flop clock circuit with an LED indicator, the LED blinks at ~0.5-second intervals despite unclear logic. Analysis reveals unstable clock triggering due to unintended button behavior causing erratic state transitions. ## Root – **Contact bounce**: Physical push buttons generate electrical noise … Read more
# Technical Postmortem: Overcoming Limitations in VS Code Syntax Highlight ## Our team encountered challenges while creating a custom VS Code theme when attempting to modify syntax highlighting colors for specific Python constructs (e.g., method calls like `classInstance.compute()`). The primary pain point was identifying the correct TextMate scopes due to ambiguous naming conventions, language-specific scope … Read more
# Python Script Crashes After One Hour: Spotify Token ## – A Python script using the Spotipy library unexpectedly crashes after approximately one hour of runtime. – The crash occurs because Spotify access tokens expire after **60 minutes** per Spotify API policy. – Without token refresh logic, subsequent API calls fail once the token expires, … Read more
# Using setTimeout() instead of step.sleep() in a Cloudflare Workflow? ## Summary A workflow relied on Cloudflare K/V writes with a strict rate limit (1 write/sec per key) after each API call. Initial mitigation used `step.sleep()` to avoid throttling, but the engineer explored substituting it with `setTimeout()` to simplify step architecture. Replacing the native sleep … Read more
Postmortem: Misunderstanding Android 9 Update Eligibility Leading to Security Risks Summary Users attempted to upgrade Android 9 devices to Android 10/11 and locate security patches without success. Root cause analysis revealed unsupported hardware, fragmented OEM policies, and discontinued security updates for legacy devices. Root Cause Hardware Compatibility: Older devices lack drivers/capabilities for newer OS versions. … Read more
Azure AD B2C Session Management: Preventing User Creation After Abrupt Session Closure Summary Azure AD B2C unexpectedly creates user profiles if a session terminates abruptly after users submit signup information. Occurs specifically during the final signup stages (e.g., post-submit/continue click), leaving the user journey incomplete. Impacts systems relying on custom policies that trigger user creation … Read more