The DOS/BATCH Verify Program

This document describes VERIFY, a DOS/BATCH program designed to diagnose and potentially repair file system issues on various disk and DECtape units. Its primary function is to evaluate the file structure, identify damage such as multiple block allocations, and report other abnormal conditions indicative of hardware malfunctions, system program errors, or user errors.

VERIFY is primarily intended for experienced programmers and requires a minimum of 16K of core (24K for RP03 disks). It supports devices including RK03, RK05, RP03, RF11 disk units, and DECtape units. The program assumes output to a line printer and input from the keyboard, with specific assignments needed for batch mode or if a line printer is unavailable. A fatal hardware disk error will abort the program.

The program offers several operational options:

1. NORMAL: Performs basic file structure verification, including checking UIC entries, files, and constructing/comparing bit maps, reporting only error messages.
2. LIST: Extends NORMAL verification by providing detailed listings of the Master File Directory (MFD), hardware and software configuration, User File Directories (UFDs) for each UIC, Core Image Library (CIL) information, Load Module details, and device bit maps.
3. SEARCH: Performs NORMAL verification and, additionally, searches for a user-specified block number, reporting the file(s) and User Identification Code (UIC) associated with it. It can also indicate if a block is unassociated or cross-allocated.
4. FIX: Performs NORMAL verification and replaces the current system bit maps with newly generated ones. This option can repair lost disk blocks but is cautioned against for severely corrupted disks or without extensive knowledge, as it can potentially corrupt the entire file system. It is only for disk units and will not proceed if cross-allocated blocks are detected.
5. ALL: Combines the functionalities of NORMAL, LIST, and SEARCH options.

Users run VERIFY by typing RUN VERIFY at the console, then specify the device (e.g., SY for system, DK for RK03/RK05 disk, DF for RF11, DP for RP03, DT for DECtape), unit number (if applicable), and the desired option. Output varies based on the chosen option, ranging from error messages to detailed file system and device information.