DDT Manual

This document contains a comprehensive source code listing for DDT, a debugging tool originally designed for the DEC PDP-1 computer. The code is written in MACRO assembly language and includes routines for symbol table management, block reading, title punching, typeout subroutines, and various diagnostic functions. The document, dated February 8, 1963, and authored by A. Kotok, serves as a fundamental reference for the implementation of early symbolic debugging on the PDP-1 system.