Linux/4004: booting Linux on Intel 4004 for fun, art, and no profit

Original Article ↗ Hacker News Discussion ↗

Overall Reaction

  • Commenters widely praise the project as “insane” and “sorcerer-level” engineering, turning an apparently impossible target into a carefully engineered reality.
  • Some see it as a vivid demonstration of how far general-purpose OSes can be stretched downwards in hardware capability.

4004 and “First Microprocessor” Debate

  • There’s an extended argument over whether the Intel 4004 should count as the first “true” microprocessor.
  • One side claims the 4004 was a calculator-specific chipset lacking core features (e.g., logical ops) and not a monolithic general-purpose CPU like the later 8008/Datapoint 2200 lineage.
  • Others counter that the 4004 is still a programmable CPU-on-a-chip and that “microprocessor” and “CPU” are social/market constructs; by most reasonable definitions (and historic impact as a product), 4004 qualifies.

Performance, Boot Time, and Multi‑Year Build

  • Current Linux boot on a real 4004 at ~790 kHz takes ~4.5 days.
  • The creator’s “art piece” goal is to have the system self‑rebuild its own kernel with swap, potentially taking years; some discuss modeling time via emulation to predict completion.
  • People compare this to correspondence chess, extremely slow music pieces, and “Linux‑by‑correspondence”.

Choice of Emulated ISA: MIPS vs RISC‑V

  • MIPS was chosen because its instruction encoding and addressing are friendlier for extremely constrained emulation.
  • RISC‑V is criticized in this context for:
    • Non-contiguous immediate fields requiring extra bit‑twiddling in software.
    • Lack of REG+REG / REG+SHIFTED_REG addressing modes and bitfield ops, seen by some as a “design deficiency.”
  • Others argue these trade-offs simplify hardware and are not fundamentally harmful, though they do make hand‑emulation less ergonomic.

Running Windows, Other OSes, and Hardware

  • Running Windows on a similar MIPS setup is deemed possible in principle but blocked by SCSI emulation complexity unless a paravirtualized disk driver is written.
  • Discussion touches on earlier/other Linux targets (386, 68020, VAX, m68k) and the continuity of “modern computing” since late ’80s/early ’90s hardware.
  • There’s curiosity about ultra-high-frequency simple cores and about porting the emulator to one-bit or vacuum‑tube machines.

Awards, Academic Merit, and Culture

  • Some suggest this deserves Nobel‑level or honorary PhD recognition; others argue it’s more in the spirit of Ig Nobel–style celebrated-but-whimsical work.
  • Several note the project as serious, meticulous engineering even if primarily “for fun, art, and no profit.”