Source: C Systems Lab Companion PDF

Repo: VHCosta/llc-companion-pdf Stack: Typst Author: VH Costa Status: All 12 chapters + 4 appendices complete; pre-launch content pass done (2026-04-24); publish-readiness gate still open (P1.6–P1.8 + PDF audit)

Value Proposition

Paid companion to the free web app, sold on Gumroad. Adds:

• Exercises with full annotated solutions (primary value)
• Deeper “why” explanations behind design decisions
• Real-world codebase connections (SQLite, Redis, CPython, Linux kernel)
• Debugging chapter (GDB, Valgrind, ASan/TSan workflows, core dumps)
• Interview prep mapped to chapters with model answers

Build Outputs

• Base (typst compile src/main.typ) — exercises only, plus one chapter-level note explaining that full solutions live in the paid tiers
• Sample (--input demo=true) — Chapters 1-3 only, selected solutions (1.2, 2.2, 3.2), one extended project (ch03), no appendices
• Solutions (--input solutions=true) — full annotated solutions
• Complete (--input solutions=true --input extended=true) — solutions + extended projects

As of the 2026-04-15 revision/QA pass:

• the base tier no longer repeats per-exercise upsell boxes
• lower tiers no longer show empty Extended Project headings
• ch01’s extended project is now real content instead of a placeholder shell
• the free sample/demo edition is a curated hybrid sample rather than a free slice of the full Complete tier

Structure

src/
├── main.typ          ← entry point, tier flags, page layout
├── template/         ← shared blocks and styling helpers
├── chapters/         ← ch01.typ – ch12.typ
└── appendix/         ← debug.typ, interview.typ, repo.typ
fonts/                ← bundled font assets passed to Typst
tests/                ← downstream mirror of canonical exercise solutions + fixtures
out/                  ← generated PDFs
build.sh              ← builds base, demo, solutions, and complete editions

Note: canonical exercise authoring now lives in llc-course/content/. This repo consumes the mirrored tests/ tree for solution-side validation rather than owning the canonical content/ source.

Chapter Status

Note: PDF chapters have their own structure independent of the web module numbering.

Chapter	PDF Title	Web Module	Status
ch01	Setup and the Compilation Model	m01-c-is-not-java (lessons 1-1, 1-2)	Written
ch02	Types, Operators, and Control Flow	m01-c-is-not-java (lesson 1-3)	Written
ch03	Pointers and the Memory Model	m02-pointers-memory-model	Written
ch04	Dynamic Memory	m03-dynamic-memory	Written
ch05	Structs, Unions, and Bit Fields	m04-structs-unions-bitfields	Written
ch06	The C Preprocessor	m05-c-preprocessor	Written
ch07	File I/O and System Calls	m06-file-io-syscalls	Written
ch08	Processes and Signals	m07-processes-signals	Written
ch09	Sockets and Networking	m08-sockets-networking	Written
ch10	Concurrency	m09-concurrency	Written
ch11	Going Below C	m10-going-below-c	Written
ch12	Game Boy Emulator (capstone)	No web counterpart	Written

Status: Shipped, With Publish Gate Still Open

All chapter-writing work is complete. The 2026-04-15 revision pass closed the main trust/content fixes, validated the product at 48 exercises / 12 chapters / 4 appendices, and left only the final publication gate open.

• Gumroad listing is live at vhcosta.gumroad.com/l/c-systems-lab ($18/$28 / $38)
• Local builds pass for all 4 outputs
• Current locally verified page counts:
  • companion.pdf: 143
  • companion-demo.pdf: 37
  • companion-solutions.pdf: 223
  • companion-complete.pdf: 236
• rendered/public metadata now aligns to 48 exercises / 12 chapters / 4 appendices
• tests/run_all.sh: 48/48 pass after the revision pass
• demo PDF includes exactly:
  • Chapters 1-3
  • solutions 1.2, 2.2, 3.2
  • ch03 extended project (Implement the String Library)

ch12 — Game Boy Emulator capstone: PDF-exclusive chapter with no web counterpart. SM83 register file, 64 KB memory bus, opcode dispatch table, ROM loader with header/checksum validation. Extended project: get Tetris booting via SDL2. See meta-gb-emulator for full implementation details.

2026-04-24 pre-launch additions:

• src/acknowledgements.typ — new closing page (all tiers; #if demo-mode branches)
• src/where-to-go.typ — new “Where to go from here” page (paid tiers only)
• src/chapters/ch12.typ — Ex 12.2b (instruction decoder) + Ex 12.2c (cartridge header parser) with full annotated solutions
• src/chapters/ch01.typ — compilation pipeline diagram (4-stage horizontal flow)
• src/chapters/ch03.typ — process virtual address space diagram (two-column: hex addresses + colored segments)

Current frontier: complete the publish-readiness gate:

• P1.6: Gumroad listing updates (screenshots, T3 description, audience line)
• P1.7: Price floor review ($25/$38 / $45)
• GUI PDF viewer audit + full visual artifact pass all 4 tiers
• P1.8: Distribution priming (HN, r/C_Programming, Bluesky)

Historical revision-pass material now lives under reviews/archive/2026-04-revision-pass/.