Could you derive the API
if the API vanished?

The hardware constraints every DOTS decision answers to

1. R The memory wall 8m
2. Q Checkpoint — the memory wall 5m
3. Unit — Mechanical Sympathy 12m

Archetypes, chunks, and structural change

1. R Archetypes — identity is a set of types 9m
2. R Chunks — why 16 KB, and what it costs you 9m
3. Q Checkpoint — archetypes & chunks 5m
4. R Tags and shared components — carrying meaning without carrying bytes 9m
5. R Queries — how iteration finds its chunks 8m
6. Q Checkpoint — components & queries 6m
7. L Watch density move 30m
8. Design the archetype for a system you haven't been given 45m
9. Unit — Entities Core 14m

The update loop, ordering, and the command-buffer boundary

1. R Systems — behaviour with no state of its own 8m
2. R Ordering — when systems run, and why it's declared 8m
3. R The command buffer — deferring the move you can't make now 9m
4. Q Checkpoint — systems, ordering, command buffers 6m
5. L Feel the sync point 30m
6. Remove every sync point from a system that must create and destroy 45m
7. Unit — Systems 14m

SIMD, aliasing, and reading the ASM

1. R Burst — a second compiler for a smaller language 8m
2. R Vectorization — one instruction, many lanes 9m
3. R Aliasing — the question the optimizer keeps asking 10m
4. Q Checkpoint — Burst, SIMD, aliasing 6m
5. R Unity.Mathematics — writing in vector width on purpose 8m
6. R Reading the ASM — proving it, not hoping it 9m
7. Q Checkpoint — math types & verification 6m
8. L Prove the vector 35m
9. Make three stubborn loops vectorize 50m
10. Unit — Burst 14m

Parallelism the compiler can prove safe

1. R Jobs — parallelism without the usual catastrophe 9m
2. R The safety system — races are aliasing, one level up 10m
3. Q Checkpoint — jobs & safety 6m
4. R IJobEntity and IJobChunk — the chunk becomes the work unit 9m
5. R Dependencies — the graph that keeps parallelism correct 10m
6. Q Checkpoint — entity jobs & dependencies 6m
7. L Spread it across cores 35m
8. Schedule a five-stage pipeline that never stalls the main thread 50m
9. Unit — Jobs 14m

How authored scenes become entity data — and why it happens offline

1. R The conversion problem — two irreconcilable data models 9m
2. R The Baker — why conversion is declared, not called 10m
3. Q Checkpoint — conversion & bakers 6m
4. R Entity scenes — why baked data loads as bytes, not as calls 9m
5. R Prefabs and blob assets — what gets shared instead of copied 10m
6. Q Checkpoint — entity scenes, prefabs & blobs 6m
7. L Price the bake — what a TransformUsageFlag costs per chunk 25m
8. Bake a spawner that survives a scene reload 45m
9. Unit — Baking 12m

Spatial data as components — and what a hierarchy costs to keep

1. R LocalTransform — why one component, and why not a matrix 9m
2. R The hierarchy — when entity data stops being independent 10m
3. Q Checkpoint — LocalTransform & the hierarchy 6m
4. R LocalToWorld — the derived value, and who owns the write 9m
5. Q Checkpoint — LocalToWorld & derived data 5m
6. L Depth costs, count doesn't — measure the hierarchy tax 30m
7. Flatten a hierarchy without breaking what it was for 50m
8. Unit — Transforms 12m

Enableable state, determinism, and controlling when work happens

1. R Enableable components — the fourth option, finally 10m
2. R Determinism — why the same inputs must give the same frame 10m
3. Q Checkpoint — enableable state & determinism 6m
4. R System groups and the fixed step — giving determinism a place to live 9m
5. Q Checkpoint — groups, fixed step & the spiral 5m
6. L Break determinism, then fix it 35m
7. Make a parallel reduction deterministic 55m
8. Unit — Advanced Patterns 12m