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Dag Lem

entity person C64 / SID #person #developer #sid #emulation #resid
sources SIDin #1–15 — Editorials and News digest (Stefano Tognon, 2002–2015) · Walleij — A SID player routine (MIDI-driven player design, note tables, hard restart) · uCApps MIDIbox SID — Wavetable Sounds Tutorial #1 (Thorsten Klose) · GoatTracker v2.72 readme (summary) · HVSC — SID file format description (PSID v1–v4, RSID) · DUET README (summary) · CheeseCutter — the repo, the man pages, and the release paper trail (2011–2026)
created 2026-08-30 · updated 2026-08-31

Author of resid, the sid emulation engine used by vice, goattracker and the sidplay2 line of sidplay players, and the person who reverse-engineered the chip's envelope ("ADSR delay") bug. The wiki knows him only through his work — every mention is a credit, a release note or a figure quoted from him.

Facts#

  • Reverse-engineered the SID's ADSR delay bug: its effects "have been reverse engineered by Dag Lem, and documented in the source code of reSID", among them a note gate delayed "up to ca. 30mS" (source: s-ucapps-wavetable-sounds-tutorial-1).
  • The hard-restart minimum: linus-walleij cites him for the timing floor — "the actual minimum time is 33 ms = 2^15 cycles according to Dag Lem, author of reSID" (hard-restart; source: s-walleij-sid-player-routine).
  • reSID releases the wiki has dates for: 0.14 (2003-01-14, external audio input emulated), 0.15 (2003, the last known bug in the ADSR-delay-bug duration removed), 0.16 (2004-06-11, a one-cycle ADSR-delay fix and, with Laurent Ganier, resampling fast enough for real time) (source: s-sidin-news-digest).
  • Kept fixing it upstream: Antti Lankila's 2007 distortion work found a filter-calculation-order bug that was "confirmed by Dag Lem and fixed in ReSID upstream" (source: s-sidin-news-digest).
  • Co-author of the PSID v2NG extension of the sid-format: the hvsc SID file format reference credits Simon White (PSID v2NG, RSID) and Dag Lem (PSID v2NG) for that revision (source: s-hvsc-sid-file-format).
  • Credited wherever reSID is embedded: "Dag Lem (reSID)" in the GoatTracker readme's collaborator list (source: s-goattracker-readme); "reSID by Dag Lem" in duet's credits (source: s-duet-readme); "reSID engine by Dag Lem & A. Lankila" in cheesecutter's README, which is what a composer in that editor actually listens to — reSID-fp is its default engine (source: s-cheesecutter-repo-and-releases).

resid · sid · hard-restart · adsr-envelope · vice · goattracker · sidplay · sid-format · linus-walleij · duet

Sources#

s-sidin-news-digest · s-walleij-sid-player-routine · s-ucapps-wavetable-sounds-tutorial-1 · s-goattracker-readme · s-hvsc-sid-file-format · s-duet-readme · s-cheesecutter-repo-and-releases

source file wiki/entities/dag-lem.md · graph