The DOS/BATCH File Dump Program FILDMP

This document describes FILDMP, a utility program for the PDP-11 Disk Operating System (DOS/BATCH). Its primary function is to aid in program debugging by generating printed copies (dumps) of file contents, either entire files or specific data blocks, for visual inspection.

FILDMP is a versatile tool that accepts input as filenames or mass storage block numbers and produces output in various readable formats. It is device-independent, meaning output can be directed to terminals, line printers, or stored on disk or tape. Users interact with FILDMP through command strings interpreted by the DOS/BATCH Command String Interpreter (CSI).

The program's operations are controlled by "switches":

• Input Switches (e.g., /BL for specific blocks, /CH to list file blocks, /FA for formatted ASCII, /FB for formatted binary) define how data is read. By default, data is read in unformatted binary. Only one type of input switch, apart from multiple /BL specifications, is permitted per command.
• Output Switches (e.g., /AS for ASCII characters, /BY for octal bytes, /OC for octal words - the default, /RA for unpacked Radix-50) determine the format of the dumped data. The /CH input switch overrides output switches, presenting block numbers in sequential order.

The output format varies based on the switches, typically including byte counts or line numbers, and can display read error messages. FILDMP identifies itself and prompts with a '#' when ready for a command, and usually indicates completion with "END OF FILE."