- DOTS (Digital Optical Technology System) was debated as a 100-year archival medium; it uses laser-induced phase-change pits on polyester tape, includes human-readable instructions for building a reader, but is write-once and after 16 years still lacks a commercial product.  
- Participants compared DOTS density (~1.5 GB per LTO-size tape assuming 1 µm pits) unfavorably to LTO-9’s native 18 TB and questioned whether future hardware or company longevity will preserve readability.  
- Microfilm/microfiche was revisited as a practical alternative: silver-halide film is considered the only archival-grade stock, but current scanners expose bare film between two glass plates, risking dust and abrasion.  
- A DIY archival concept emerged: etch a helical pixel pattern on a hard cylinder, then indent that pattern into gold-sputtered metal ribbon; uncompressed text + thumbnails would occupy the foreground while compressed data hides in grayscale dithering or diffraction patterns to survive physical fragmentation.  
- Fountain codes (Luby Transform, Raptor) were discussed for redundancy; Lev noted they can be implemented with simple XOR and Gaussian elimination, while fenn preferred embedding decoder instructions redundantly across the medium to aid post-apocalyptic or far-future recovery.  
- kanzure linked a Bitcoin Core dev tech transcript archive (btctranscripts.com) and two AI papers: “Memory Synthesis” on learnable activation functions and the new “Kolmogorov-Arnold Networks” (KANs) that replace every MLP weight with a spline-parameterized univariate function on edges.