thumb|300px|<code>DDT86.CMD</code> in [[Digital Research CP/M-86 for the IBM Personal Computer Version 1.0]]

Dynamic Debugging Technique (DDT) is a series of debugger programs originally developed for Digital Equipment Corporation (DEC) hardware, initially known as DEC Debugging Tape because it was distributed on paper tape. The name is a pun on the insecticide DDT, which "kills bugs".

The first version of DDT was developed at MIT for the PDP-1 computer in 1961. It was an adaptation of the early interactive, symbolic debugger FLIT (the "Flexowriter Interrogation Tape", itself a play on the name of a once-popular brand of insect spray), developed for MIT's TX-0 computer in 1959. Newer versions of DDT on newer platforms continued to use the acronym DDT, but the name "Dynamic Debugging Technique", introduced by 1965, prevailed by the late 1960s. Early versions of Digital Research's CP/M and CP/M-86 kept the name DDT (and DDT-86 and DDT-68K<!-- both with hyphen -->) for their debugger, reinterpreted as Dynamic Debugging Tool.

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  • DDT Command List for a freeware version written in portable C
  • ITS 1.5 Reference Manual -(Artificial Intelligence Memo No. 161A)
  • ITS: Luser's Guide
  • The Great Quux Poem Collection -(See especially the notes to the poem The HACTRN)