Dynamic Debugging Tool
| Company type | Software |
|---|---|
| Industry | Computer software, Debugging tools |
| Founded | 1961 |
| Founder | MIT developers |
| Products | Debugger utilities for DEC machines, CP/M, CP/M-86 |
Dynamic Debugging Technique (DDT) refers to a collection of debugger utilities originally designed for Digital Equipment Corporation (DEC) machines. Initially named DEC Debugging Tape because it was distributed on paper tape, the first iteration of DDT was developed at MIT in 1961 for the PDP-1. Subsequent versions preserved the DDT designation across various platforms. As the tool extended its reach beyond DEC hardware, it came to be known as the Dynamic Debugging Tool. Early implementations of Digital Research's CP/M and CP/M-86 incorporated DDT (including variants like DDT-86 and DDT-68K) as their primary debugging utility. Eventually, the CP/M DDT was supplanted by the Symbolic Instruction Debugger (SID, ZSID, SID86, and GEMSID) within DR DOS and the GEM environment.
In addition to its debugging capabilities, DDT served as a principal command shell on MIT's Incompatible Timesharing System (ITS). It was capable of controlling and debugging multiple simultaneous processes ("jobs"), up to eight at once, including nested executions of itself. The original top-level incarnation of DDT was called "HACTRN" ("hack-tran"), which inspired a filk poem parody authored by Guy L. Steele.
DEC-10/DEC-20 DDT
On the DECsystem-10 and DECSYSTEM-20, DDT provided support for symbol resolution directly from executable files, facilitating debugging tasks. A specialized version named SDDT accessed symbols from the active monitor, allowing system developers to examine internal system behavior.
See also
- On-line Debugging Tool (ODT)
- Tracing Debugging Technique (TDT)
- DEBUG (DOS command)
- Comparison of computer shells
External links
- Command List for a freeware DDT version implemented in portable C
- ITS 1.5 Reference Manual – (Artificial Intelligence Memo No. 161A)
- ITS: Luser's Guide
- The Great Quux Poem Collection – (Refer to notes on the poem The HACTRN)