archy/demo/content/documents/bitcoin-whitepaper-notes.md

# Bitcoin Whitepaper Notes

## Key Concepts

### Peer-to-Peer Electronic Cash
- No trusted third party needed
- Double-spending solved via proof-of-work
- Longest chain = truth

### Proof of Work
- SHA-256 based hashing
- Difficulty adjusts every 2016 blocks (~2 weeks)
- Incentive: block reward + transaction fees

### Network
- Nodes broadcast transactions
- Miners collect into blocks
- Blocks are chained via hash references

## My Thoughts
- The 21M supply cap is genius - digital scarcity
- Lightning Network solves the scaling concern
- Self-custody is the whole point

## Reading List
- [ ] Mastering Bitcoin - Andreas Antonopoulos
- [ ] The Bitcoin Standard - Saifedean Ammous
- [ ] Programming Bitcoin - Jimmy Song
release(v1.7.41-alpha): post-OTA auto-rollback so a bad release cannot strand the fleet Closes failure mode FM5 from docs/bulletproof-containers.md: the v1.7.38 + v1.7.39 rollouts left every affected node on an unreachable UI (nginx 500) with no recovery path short of SSH. This release adds a self-check guardrail to the update flow. What changed: - apply_update() writes a pending-verify marker with old+new version and a 150s deadline immediately before scheduling the service restart. - verify_pending_update() runs from main.rs startup. If the marker is present and within its freshness window, the new binary waits 15s for nginx + backend to settle, then probes https://127.0.0.1/ every 5s for up to 90s (self-signed certs accepted). - On any probe success within the window, the marker is cleared and nothing else happens. - On window-exhaust, the new binary: 1. Moves the broken /opt/archipelago/web-ui to web-ui.failed.<ts> (quarantined, not deleted, so we can post-mortem). 2. Restores web-ui.bak on top of web-ui. 3. Calls rollback_update() to restore the previous binary. 4. Updates state.current_version to reflect the rollback. 5. systemctl --no-block restart archipelago so the OLD binary boots. - Markers older than 10 minutes are treated as stale and cleared without probing, so a crashed-during-startup marker from weeks ago cannot spontaneously roll back a healthy node on a later reboot. - rollback_update() binary copy now goes through host_sudo instead of tokio::fs::copy, so it escapes the service's ProtectSystem=strict mount namespace. Without this, the rollback silently failed with EROFS on /usr/local/bin and orphaned the rollback - the exact opposite of what auto-rollback is for. Tests: 4 new unit tests in update::tests covering marker round-trip, absent-marker noop, no-panic on verify_pending_update with nothing to verify, and an invariant assert that the 90s probe window stays below the 600s stale threshold. All passing. Side fix: scripts/create-release-manifest.sh was dying with exit 141 (SIGPIPE from tar tvzf pipe head pipe awk) under set -euo pipefail. Replaced with a single awk NR==1 that doesn't short-circuit the upstream pipe, so the release-build flow is idempotent again. 2026-04-22 16:14:35 -04:00			`# Bitcoin Whitepaper Notes`

			`## Key Concepts`

			`### Peer-to-Peer Electronic Cash`
			`- No trusted third party needed`
			`- Double-spending solved via proof-of-work`
			`- Longest chain = truth`

			`### Proof of Work`
			`- SHA-256 based hashing`
			`- Difficulty adjusts every 2016 blocks (~2 weeks)`
			`- Incentive: block reward + transaction fees`

			`### Network`
			`- Nodes broadcast transactions`
			`- Miners collect into blocks`
			`- Blocks are chained via hash references`

			`## My Thoughts`
			`- The 21M supply cap is genius - digital scarcity`
			`- Lightning Network solves the scaling concern`
			`- Self-custody is the whole point`

			`## Reading List`
			`- [ ] Mastering Bitcoin - Andreas Antonopoulos`
			`- [ ] The Bitcoin Standard - Saifedean Ammous`
			`- [ ] Programming Bitcoin - Jimmy Song`